Information processing device, information processing method, and program

Abstract

The present technology relates to an information processing device, an information processing method, and a program that make it possible to provide sound at a volume desired by a user. This information processing device comprises: a setting unit that sets a partial band out of the band of a sound to be processed as an inversion frequency band, and sets the other band as a non-inversion frequency band; and an output unit that outputs an addition signal obtained by adding an inversion signal obtained by inverting the phase of a first signal sound corresponding to the inversion frequency band and a second signal sound corresponding to the non-inversion frequency band in synchronization with the sound to be processed before processing. The setting unit changes the partial band in response to a prescribed input. The present technology can be applied to, for example, a reproduction device.

Description

Information processing device, information processing method, and program

[0001] The present technology relates to an information processing device, an information processing method, and a program, and more particularly to an information processing device, an information processing method, and a program that perform signal processing applying binaural masking level difference (BMLD), which is one of human auditory psychological phenomena.

[0002] Conventionally, a technology has been proposed for emphasizing sounds that are desired to be heard by signal processing that applies the binaural masking level difference (BMLD), which is one of the human psychoacoustic phenomena.

[0003] For example, Patent Document 1 proposes that when listening to sound from earphones or headphones in a noisy environment, signal processing using BMLD can be performed to psychologically increase the volume of the sound that is desired to be heard (target sound) and make it easier to hear.

[0004] International Publication No. 2023 / 189789

[0005] When performing signal processing using BMLD, it is desirable to be able to adjust the volume so that the listener can hear at a volume that is appropriate for them while preventing the listener from experiencing an unnatural listening sensation.

[0006] The present technology has been developed in consideration of such circumstances, and when performing signal processing using BMLD, it makes it possible to gradually change the volume by changing the magnitude of the BMLD effect that emphasizes the target sound.

[0007] An information processing device according to one aspect of the present technology includes a setting unit that sets a portion of a band of a sound to be processed as an inverted frequency band and other bands as non-inverted frequency bands, and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, wherein the setting unit changes the portion of the band in response to a predetermined input.

[0008] An information processing method according to one aspect of the present technology is an information processing method in which an information processing device that processes sound includes a setting unit and an output unit, wherein the setting unit sets a portion of a band of a sound to be processed as an inverted frequency band and another portion as a non-inverted frequency band, and the output unit outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, and the setting unit includes processing to change the portion of the band in response to a predetermined input.

[0009] A program according to one aspect of the present technology is a program for causing a computer to function as a setting unit that sets some bands of a band of a sound to be processed as inverted frequency bands and other bands as non-inverted frequency bands, and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, wherein the setting unit includes a function to change the some bands in response to a predetermined input.

[0010] In an information processing device, an information processing method, and a program according to one aspect of the present technology, a portion of the band of a sound to be processed is set as an inverted frequency band and another portion is set as a non-inverted frequency band, and an added signal obtained by adding an inverted signal in which the phase difference of a first signal sound corresponding to the inverted frequency band is inverted and a second signal sound corresponding to the non-inverted frequency band is output in synchronization with the sound to be processed before processing.

[0011] The information processing device may be an independent device or an internal block constituting a single device.

[0012] The program can be provided by transmitting it via a transmission medium or by recording it on a recording medium.

[0013] 1 is a diagram for explaining an overview of BMLD. FIG. 2 is a diagram showing an example of frequency characteristics of BMLD. FIG. 3 is a diagram showing an example of a signal processing method according to a comparative example. FIG. 4 is a diagram showing an example of a signal processing method according to the present embodiment. FIG. 5 is a diagram for explaining a transition from physical sound pressure adjustment to psychological sound pressure adjustment. FIG. 6 is a diagram for explaining the relationship between volume adjustment value and sound pressure adjustment. FIG. 7 is a diagram for explaining the range of an inversion frequency band. FIG. 8 is a diagram for explaining a change pattern. FIG. 9 is a diagram for explaining a curve of a change pattern. FIG. 10 is an example of a graph showing the relationship between volume adjustment value and inversion frequency. FIG. 11 is an example of a graph showing the relationship between volume adjustment value and inversion frequency. FIG. 12 is an example of a graph showing the relationship between volume adjustment value and inversion frequency. FIG. 13 is a diagram showing an example of a user interface. FIG. 14 is a diagram showing an example of a configuration of a playback device according to a first embodiment. FIG. 15 is a diagram showing an example of a configuration of a playback device according to the first embodiment. FIG. 16 is a flowchart for explaining first volume processing. FIG. 17 is a flowchart for explaining second volume processing. FIG. 18 is a diagram showing an example of a configuration of a playback device according to a second embodiment. FIG. 19 is a diagram showing an example of a configuration of a playback device according to a third embodiment. FIG. 19 is a diagram showing another example of a graph. FIG. 2 is a diagram illustrating an example of the configuration of a PC.

[0014] Hereinafter, modes for carrying out the present technology (hereinafter referred to as embodiments) will be described.

[0015] For example, when listening to sound using earphones or headphones, if a user continues to listen to sound at a relatively high volume, there is a risk of hearing loss. By applying the present technology described below, even if a user continues to listen to sound at a relatively high volume, hearing loss can be prevented and the user can enjoy sound at a desired volume. Here, a playback device that uses binaural masking level difference (BMLD) to prevent hearing loss and allows the user to enjoy sound at a desired volume will be described as an example.

[0016] An overview of BMLD, which is one of the human psychological auditory phenomena, will be described below. FIG. 1 is a diagram for explaining the overview of BMLD. In FIG. 1, "S" indicates the sound signal of a target sound, which is the sound that one wants to hear, and "N" indicates the sound signal of a masker, which is an interfering sound that blocks the target sound. "O (S or N) 0" indicates that there is no phase difference between the sounds at both ears (left and right). "O (S or N) π" indicates that the sounds at both ears (left and right) are in opposite phase to each other. "O (S or N) u" indicates that there is no correlation between the sounds at both ears (left and right).

[0017] Masking refers to the phenomenon in which a target sound becomes difficult to detect when a masker is present. When the masker sound pressure is constant, the sound pressure level of the target sound at which the target sound can just barely be detected through the masker is called the masking threshold.

[0018] As shown in patterns A and B in Figure 1, BMLD is the difference between the masking threshold when an in-phase target sound is heard under an in-phase masker (e.g., white noise) and the masking threshold when an out-of-phase target sound is heard between the two ears under an in-phase masker (white noise). BMLD occurs even when the phase difference of the target sound between the two ears is changed to any value other than 180 degrees (π), but BMLD is maximized when the phase difference of the target sound between the two ears is 180 degrees (π), making the target sound easier to hear.

[0019] For example, a study has shown that when listening to a target sound in opposite phase between the ears in the same white noise environment, the phase-inverted target sound gives the listener a psychological increase in volume equivalent to 15 dB (decibels) (Hirsh, IJ (1948). "The influence of interaural phase on interaural summation and inhibition." Journal of the Acoustical Society of America, 20, 536-544. Internet URL: https: / / doi.org / 10.1121 / 1.1906407).

[0020] BMLD also occurs when the target sound between the two ears remains in phase while the masker (e.g., white noise) is made uncorrelated between the two ears, as shown in patterns A and C in Figure 1. For example, verification results have shown that in this case, listeners experience a psychological increase in volume equivalent to 13 dB (decibels). Thus, BMLD has been shown to have the effect of making the target sound easier to hear in a masker environment (hereinafter referred to as the "BMLD effect").

[0021] However, when BMLD processing is performed, sounds that have undergone phase inversion processing can have a "crinkly" auditory sensation, appearing to the listener as floating, and can give an unnatural auditory sensation. The cause of this auditory sensation is thought to be the human auditory peripheral organ. Sound entering the ear is broken down into frequencies by the cochlea in the inner ear, and the phase difference between the sounds between the two ears is then calculated in a processing mechanism called the brainstem, which is the entrance to the brain. While the phase difference between the sounds between the two ears is easily perceived, especially in the low frequency band, it may be difficult to perceive in the high frequency band.

[0022] According to an information processing device of an embodiment according to the present disclosure, it is possible to solve problems that may arise in the auditory sense of a listener when BMLD processing is performed. The information processing device of an embodiment according to the present disclosure performs signal processing to invert the phase of only sound components in a specific frequency band of a target sound, thereby solving problems that may arise in the auditory sense of a listener when BMLD processing is performed.

[0023] As will be explained below, when the frequency band of the target sound to be phase-inverted is limited, the effect of BMLD is reduced compared to when the entire frequency band is phase-inverted, but this fact can be utilized to adjust the effect of making the target sound easier to hear.

[0024] An information processing device according to an embodiment of the present disclosure aims to use the above-described features to adjust the volume of a target sound to a listener's desired volume. The information processing device according to an embodiment of the present disclosure can change the magnitude of the BMLD effect and control the volume of the target sound by changing the range of the frequency band of the target sound that is phase-inverted.

[0025] The frequency band to be phase-inverted is dynamically set according to the volume adjustment value specified by the user. The frequency band is set according to the volume adjustment value specified by the user, and signal processing is executed to invert the phase of only the signal in the set frequency band, thereby making it possible to gradually change the volume while solving problems with the listener's hearing that may arise when BMLD processing is executed.

[0026] In the following, a playback device will be described as an example of an information processing device of the present disclosure. Examples of playback devices include audio playback devices, communication terminals such as smartphones, and personal computers. The playback device is not limited to existing playback devices, and may be a new playback device as long as it is a device that plays stereo sound. It is assumed that the sound signals processed by the signal processing method according to the embodiment are listened to using a sound output device such as stereo playback earphones or headphones. Furthermore, a listener wearing the sound output device will be simply referred to as a "user."

[0027] In the following description, among the frequency bands of the target sound, a frequency band that is subject to phase inversion processing is referred to as an "inversion frequency band." Among the frequency bands of the target sound, a frequency band that is not subject to phase inversion processing is referred to as a "non-inversion frequency band." Dividing the frequency of a sound during signal processing is referred to as band division.

[0028] The inversion frequency band described above may be set to a unique value according to the frequency distribution of the sound, for example, by analyzing in advance the music or voice played on the playback device. The inversion frequency band described above may change from time to time according to the frequency distribution of the target sound. The boundary line of the inversion frequency may be changed sequentially according to the noise level. The inversion frequency band may have a band-pass characteristic. The target sound is not limited to voice, but may also be music. The frequency distribution of noise may also be analyzed as needed, and the boundary value of the inversion frequency band of the target sound may be determined according to the frequency distribution of the noise.

[0029] It is known that the magnitude of BMLD is frequency dependent. Figure 2 is a diagram showing an example of the frequency characteristics of BMLD. As shown in Figure 2, when the target sound is a sine wave, BMLD is maximized when the frequency of the target sound is 200 Hz (Hertz) (this frequency will be referred to as the "maximum BMLD frequency").

[0030] As the frequency of the target sound increases, the BMLD decreases. Furthermore, near the maximum BMLD frequency, the BMLD increases or decreases rapidly even with small changes in frequency, whereas in the high-frequency band, the BMLD remains almost constant even with changes in frequency. Thus, the inversion frequency band may be determined taking into consideration the frequency dependency of the BMLD magnitude (described later).

[0031] The signal processing performed by the information processing device of the present disclosure is expected to be utilized in environments where noise is expected, such as on a train or in a crowded area (hereinafter referred to as a "noisy environment"). With this information processing device, when listening to a sound source pre-stored in a playback device or sound played online (such as music content or audio content) through headphones in a noisy environment, or when making a call through the playback device, it is expected that the target sound, such as music, voice, or call voice, will be easier to hear even if the volume adjustment value is increased, without physically amplifying the target sound. Furthermore, because the target sound is not physically amplified, it is expected to reduce the risk of hearing loss caused by listening to sound through headphones for long periods of time.

[0032] <Outline of signal processing method according to comparative example> An outline of signal processing according to a comparative example to the signal processing performed by the information processing device of the present disclosure will be described. Fig. 3 is a diagram showing an example of a signal processing method according to the comparative example.

[0033] 3, the playback device 100EX according to the comparative example duplicates a target sound (monaural signal) to be reproduced in a noisy environment (step S1). The duplicated target sound is treated as sound signals for two channels, left and right.

[0034] The playback device 100EX according to the comparative example inverts the phase of one of the two-channel sound signals (step S2). Note that the playback device 100EX according to the comparative example does not invert the phase of the other sound signal.

[0035] The playback device 100EX according to the comparative example outputs a phase-inverted sound signal and a phase-uninverted sound signal to the sound output device 10EX while synchronizing them. For example, the playback device 100EX outputs the phase-inverted sound signal of the two-channel sound signals through the functional channel and outputs the phase-uninverted sound signal through the non-functional channel.

[0036] For example, the playback device 100EX outputs a phase-inverted sound signal to a unit for the left ear corresponding to the functional channel (Lch) in the sound output device 10EX, and outputs a phase-uninverted sound signal to a unit for the right ear corresponding to the non-functional channel (Rch) in the sound output device 10EX (step S3).

[0037] As a result, the sound output device 10EX can provide a target sound to which the BMLD effect has been added to a user wearing the sound output device 10EX in a noisy environment.

[0038] <Outline of Signal Processing Method According to First Embodiment> An outline of a signal processing method according to an embodiment of the present disclosure will be described below. The signal processing method according to the embodiment of the present disclosure differs from the signal processing method according to the comparative example in that the signal processing method inverts the phase of only a frequency band (inversion frequency band) of a target sound that corresponds to a volume specified by a user.

[0039] For example, in a signal processing method according to an embodiment of the present disclosure, when a volume designated by a user (hereinafter referred to as a designated volume) is greater than a predetermined volume (referred to as a threshold value Vth), psychological sound pressure adjustment using BMLD is performed. Psychological sound pressure adjustment is a process of adjusting the sound pressure using BMLD so that the user feels that the desired volume has been achieved, without changing the magnitude of the amplitude (maximum amplitude) of the waveform of the sound signal.

[0040] When the designated volume is close to the threshold value Vth, the inversion frequency band is set to a narrow band, and when the designated volume is farther away than the threshold value Vth, the inversion frequency band is set to a wide band, and psychological sound pressure adjustment is performed in the inversion frequency band set according to the volume.

[0041] By adjusting the inversion frequency band to match the specified volume, it becomes possible to gradually change the psychological sound pressure. By setting the inversion frequency band to a frequency band that is less likely to affect the perception of interaural (between the left and right ears) phase difference in sound, it is possible to adjust how the sound is heard, for example, by making it easier to hear the higher frequencies of the target sound frequency band, where interaural phase difference is less likely to be perceived.

[0042] 4 is a diagram illustrating an example (overview) of a signal processing method according to an embodiment of the present disclosure. As shown in FIG. 4, a playback device 100 according to the embodiment duplicates a target sound (monaural signal) to be reproduced in a noisy environment (step S11). Here, the playback device 100 temporarily stores either the target sound (original sound signal) or a duplicate sound (duplication signal) obtained by duplicating the target sound. The target sound may be any sound, such as music or speech.

[0043] If the specified volume is greater than the threshold Vth, the playback device 100 selects either the target sound (original sound signal) or a duplicated sound (duplicate signal) of the target sound as the sound to be processed, sets a portion of the band of the sound to be processed as an inversion frequency band to be subject to phase inversion, and sets the other bands as non-inversion frequency bands not to be subject to phase inversion (step S12).

[0044] For example, the playback device 100 performs frequency analysis on either the original sound signal or the duplicated signal (hereinafter collectively referred to as "sound signal") and divides the sound signal in the frequency domain. Specifically, the playback device 100 divides the sound signal into an inverted frequency band and a non-inverted frequency band based on the frequency characteristics of the sound signal obtained by the frequency analysis.

[0045] When the inverted frequency band is a voice of a specific person or a sound of a specific instrument, a unique value may be determined for each person or each instrument by analyzing the frequency power distribution in advance, etc. The inverted frequency band may change from moment to moment depending on the frequency distribution.

[0046] The reproduction device 100 may determine the inverted frequency band of the target sound by utilizing the frequency dependency of BMLD, as described above. While Fig. 4 shows an example of the frequency characteristics of the target sound, the frequency components contained in the target sound are not limited to those shown in Fig. 4 . Even when the target sound contains any frequency components, the inverted frequency band of the target sound can be determined by utilizing the frequency dependency of BMLD. The setting of these inverted frequency bands will be described later with reference to Fig. 8 and subsequent figures.

[0047] The playback device 100 inverts the phase of the first sound signal, which belongs to an inverted frequency band in the sound signal band (step S13), to generate an inverted signal. The playback device 100 adds the inverted signal to a second sound signal, which belongs to a non-inverted frequency band in the sound signal band (step S14), to generate an added signal. In this way, the playback device 100 partially imparts the BMLD effect to the target sound.

[0048] The playback device 100 synchronizes the added signal generated in step S14 with the original sound signal or the copy signal that has been temporarily stored, and outputs the resulting signal to the sound output device 10 (step S15).

[0049] In this way, the playback device 100 according to the embodiment of the present disclosure can dynamically change the inversion frequency band according to the specified volume, thereby changing the effect of the BMLD while providing the listener with a natural listening experience, and allowing the listener to listen at the volume they desire.

[0050] <Regarding Volume Switching Settings> With reference to FIG. 5, a case will be described in which the user specifies the volume using a UI (User Interface) displayed on the playback device 100, and psychological sound pressure adjustment is performed in accordance with the specified volume.

[0051] The left diagram in Fig. 5 shows a UI displayed on the display unit 101 of the playback device 100. The playback device 100 shown in Fig. 5 includes a display unit 101, which is configured as a touch panel. A volume adjustment operation unit 121 for adjusting the volume is displayed on the display unit 101.

[0052] The volume adjustment operation unit 121 is formed by a slider and a knob, and is configured so that a desired volume can be set by moving the knob. The volume is set to be louder as the knob on the slider of the volume adjustment operation unit 121 is moved to the right in the figure.

[0053] 5 is a diagram for explaining the relationship between the volume (designated volume) set by the user by operating the volume adjustment operation unit 121 and the sound pressure adjustment, and the relationship between the inverted frequency band when the sound pressure is adjusted. When the designated volume is from 0 to the threshold value Vth, physical sound pressure adjustment is performed.

[0054] Physical sound pressure adjustment is an adjustment that physically amplifies or attenuates the waveform of the sound signal itself. The speaker contained in the earphone includes a diaphragm, and when the volume is set high, the vibration of the diaphragm also increases. In physical sound pressure adjustment, the volume (sound pressure) is adjusted by changing the amplitude of the vibration of the diaphragm. In physical sound pressure adjustment, the volume is adjusted by adjusting the amplitude of the sound signal waveform.

[0055] When the designated volume is set to a threshold value Vth or higher, psychological sound pressure adjustment is performed. In psychological sound pressure adjustment, the volume is adjusted so that the maximum amplitude of the waveform of the sound signal remains unchanged. The frequency band for psychological sound pressure adjustment is set according to the designated volume. The graph shown in the upper right of Figure 5 is a graph showing the change in the inversion frequency band during psychological sound pressure adjustment, with the horizontal axis representing the volume adjustment value and the vertical axis representing the inversion frequency band.

[0056] Psychological sound pressure adjustment is performed from the volume adjustment value threshold Vth (volume adjustment value Vth) to the maximum volume adjustment value (volume adjustment value Vmax), and as the volume adjustment value gradually increases from volume adjustment value Vth to volume adjustment value Vmax, the frequency band of the inversion frequency is also widened in accordance with this change. At volume adjustment value Vth, the inversion frequency band is set to a part on the high frequency Fh side, but the frequency band is gradually widened, and at volume adjustment value V1, the inversion frequency band is widened from the high frequency Fh to frequency F1.

[0057] Furthermore, at the volume adjustment value Vmax, the frequency range from frequency Fh to frequency FL (the smallest frequency among the frequencies set as the inversion frequency band) is set as the inversion frequency band.

[0058] The psychological sound pressure can be adjusted by the magnitude of the inversion frequency band. In the example shown in Fig. 5, the sound pressure is gradually increased physically from the volume adjustment value 0 to the threshold value Vth through physical sound pressure adjustment, and the sound pressure is gradually increased psychologically from the threshold value Vth to the maximum value Vmax through psychological sound pressure adjustment.

[0059] For example, when the volume adjustment value is designed with a scale ranging from 0 to 100, one scale of the volume adjustment value does not necessarily correspond to 1 dB of sound pressure, so the volume adjustment value is converted to dB units. Physical sound pressure adjustment or psychological sound pressure adjustment is performed so that the volume is set to the volume specified by the user. This will be explained further with reference to FIG. 6.

[0060] Figures 6A and 6B each show an example in which the volume adjustment value can be set in 10 steps from 0 to 10, and are figures for explaining the relationship between the volume adjustment value and the amplification value converted to dB units when the volume adjustment value is set so that when the volume adjustment value is between the 1st and 5th scales the volume is adjusted by physical sound pressure adjustment, and when the volume adjustment value is between the 6th and 10th scales the volume is adjusted by psychological sound pressure adjustment.

[0061] 6A shows a case where the volume adjustment value increases by 0.5 dB when it is increased by one scale. For example, when the volume adjustment value is changed from 1 scale to 2 scale, the volume is increased by 0.5 dB by physical sound pressure adjustment. For example, when the volume adjustment value is changed from 6 scale to 7 scale, the volume is increased by 0.5 dB by psychological sound pressure adjustment.

[0062] In the example shown in Figure 6A, the volume adjustment value is designed on a scale ranging from 1 to 10, and the volume is adjusted so that one scale of the volume adjustment value corresponds to a sound pressure of 0.5 dB. In this way, it is possible to set the volume adjustment value so that the increase in volume converted to dB is amplified in proportion to the increase in volume adjustment value.

[0063] Because human perception is nonlinear, if the volume adjustment value is set to increase linearly by 0.5 dB each time the volume adjustment value is increased by one scale, as in the example shown in A of Fig. 6, people may not perceive the volume as being amplified linearly. Therefore, the volume may be adjusted nonlinearly, as shown in B of Fig. 6.

[0064] 6B shows a case where the volume is adjusted in dB, so that when the volume adjustment value is increased by one scale, the user feels as if the volume has increased by one scale. For example, if the user has the characteristic that the difference in volume is not noticeable when the volume is low and is easily noticeable when the volume is high, the change in the amplification value converted into dB is large when the volume adjustment value is low, and the change in the amplification value converted into dB is small when the volume adjustment value is high.

[0065] For example, when the volume adjustment value is changed from 1 scale to 2 scale, the volume is increased by 1 dB due to physical sound pressure adjustment. When the volume adjustment value is changed from 2 scale to 3 scale, the volume is increased by 1 dB due to physical sound pressure adjustment. When the volume adjustment value is changed from 3 scale to 4 scale, the volume is increased by 0.9 dB due to physical sound pressure adjustment. When the volume adjustment value is changed from 4 scale to 5 scale, the volume is increased by 0.7 dB due to physical sound pressure adjustment. When the volume adjustment value is changed from 5 scale to 6 scale, the volume is increased by 0.6 dB due to physical sound pressure adjustment.

[0066] When the volume adjustment value is changed from 6 to 7, the volume is increased by 0.5 dB due to psychological sound pressure adjustment. When the volume adjustment value is changed from 7 to 8, the volume is increased by 0.4 dB due to psychological sound pressure adjustment. When the volume adjustment value is changed from 8 to 9, the volume is increased by 0.3 dB due to psychological sound pressure adjustment. When the volume adjustment value is changed from 9 to 10, the volume is increased by 0.2 dB due to psychological sound pressure adjustment.

[0067] In the example shown in Fig. 6B, the volume adjustment value is designed on a scale ranging from 1 to 10, and the volume is adjusted nonlinearly with an amplification amount per volume adjustment value scale. In this way, it is possible to set the increase in the volume adjustment value and the increase in the volume converted to dB units to be amplified nonlinearly.

[0068] The graph showing the relationship between the volume adjustment value and the inversion frequency band, which will be described below, can be a graph in which the frequency band is designed so that when the user specifies an increase in volume by one scale in psychological sound pressure adjustment, the user feels that the volume has increased by one scale. A further explanation of such a graph will be provided below.

[0069] <Relationship Between Volume Adjustment Value and Inversion Frequency Band> The relationship between the volume adjustment value and the inversion frequency band will now be explained. An example of the relationship between the volume adjustment value and the inversion frequency is shown in the graph in Figure 5. The graph showing the relationship between the volume adjustment value and the inversion frequency shown in Figure 5 is composed of two elements: a change pattern and the curve shape of the graph.

[0070] The change pattern is the pattern of the frequency at which the inversion begins and the band is expanded as the volume adjustment value changes. The curve shape of the graph is the shape of the curve on the graph of the volume adjustment value and the inversion frequency, and is the shape of the boundary between the inverted frequency band and the non-inverted frequency band.

[0071] In the following description, the range treated as the inversion frequency will be explained with reference to FIG. 7. The range treated as the inversion frequency can be, for example, the frequency band of the sound signal. A configuration can be made in which a graph, described below, is created and processed for frequencies within the frequency band of the sound signal. The frequency band of the sound signal can be, for example, 0 Hz to 24 kHz. When the inversion frequency is set to 0 Hz to 24 kHz, the minimum value of the inversion frequency is treated as 0 Hz and the maximum value is treated as 24 kHz.

[0072] The range treated as the inversion frequency can be, for example, the audible range. Because the audible range differs from user to user, the audible range may be measured for each user and set based on the measurement. A graph, described below, can be created and processed for frequencies within the set audible range. The audible range can be, for example, 20 Hz to 20 kHz. When the inversion frequency is set to 20 Hz to 20 kHz, the minimum value of the inversion frequency is treated as 20 Hz, and the maximum value is treated as 20 kHz.

[0073] The range treated as the inversion frequency can be, for example, the main range in which the effect of BLMD is obtained. A configuration can be made in which a graph, described below, is created and processed for frequencies within the main range in which the effect of BLMD is obtained. The main range in which the effect of BLMD is obtained can be, for example, 20 Hz to 5000 Hz. When the inversion frequency is set to 20 Hz to 5000 kHz, the minimum value of the inversion frequency is treated as 20 Hz and the maximum value as 5000 kHz.

[0074] Although three ranges are shown here as examples of ranges that are treated as inversion frequencies, ranges other than these may also be set within the scope of application of the present technology.

[0075] Any one of the three ranges illustrated here can be used to create and process the graphs described below, or two or three ranges can be used in combination to create and process the graphs described below.

[0076] In the above and following descriptions, the numerical values ​​are merely examples and are not limiting.

[0077] An example of a change pattern is shown in Fig. 8. In each change pattern shown in Fig. 8, the horizontal axis represents the volume adjustment value, the vertical axis represents the inversion frequency, and the volume adjustment value at the origin is the threshold value Vth.

[0078] The change pattern A shown in FIG. 8A is a pattern in which the inversion frequency band gradually widens from the high frequency side to the low frequency side as the volume adjustment value increases.

[0079] The change pattern B shown in FIG. 8B is a pattern in which the inversion frequency band gradually widens from the low frequency side to the high frequency side as the volume adjustment value increases.

[0080] The change pattern C shown in FIG. 8C is a pattern in which the inversion frequency band is gradually widened from the high frequency side to the low frequency side and from the low frequency side to the high frequency side as the volume adjustment value increases.

[0081] Change pattern D shown in FIG. 8D is a pattern in which, as the volume adjustment value increases, the inversion frequency band gradually expands toward the low frequency side and the high frequency side from a frequency located approximately midway between the maximum and minimum frequencies set as the inversion frequency.

[0082] The change pattern E shown in FIG. 8E is a pattern in which the inversion frequency band remains constant regardless of an increase in the volume adjustment value.

[0083] The shape of the boundary between the inverted frequency band and the non-inverted frequency band in each of patterns A to E shown in Fig. 8 is a straight line. The shape of the boundary between the inverted frequency band and the non-inverted frequency band may be a curved line as shown in Fig. 9.

[0084] In the curve pattern A shown in Fig. 9A, the boundary between the inverted frequency band and the non-inverted frequency band has a downwardly convex shape. In the curve pattern A shown in Fig. 9A, the inverted frequency band is rapidly widened as the volume adjustment value increases near low volumes, for example, near the threshold value Vth. For example, in the case of a volume adjustment value V1, the inverted frequency band is band 7a.

[0085] In the curve pattern B shown in Fig. 9B, the boundary between the inverted frequency band and the non-inverted frequency band has an upwardly convex shape. In the curve pattern B shown in Fig. 9B, the inverted frequency band gradually widens as the volume adjustment value increases near low volumes, for example, near the threshold value Vth. For example, when the volume adjustment value is V1, the inverted frequency band is band 7b.

[0086] When the volume adjustment value V1 in curve pattern A shown in FIG. 9A and the volume adjustment value V1 in curve pattern B shown in FIG. 9B are the same value and the inversion frequency band 7a and the inversion frequency band 7b are compared, the relationship of inversion frequency band 7a > inversion frequency band 7b is satisfied.

[0087] In this way, the curve pattern can be designed so that the magnitude of the inversion frequency band at a given volume adjustment value varies. As an example, the curve pattern is designed so that the inversion frequency band is set so that one scale division corresponds to a volume adjustment value of 1 dB.

[0088] The change pattern shown in FIG. 8 and the curve pattern shown in FIG. 9 are merely examples and are not intended to be limiting.

[0089] The combination of the change patterns A to E shown in Fig. 8 and the curved patterns A and B shown in Fig. 9 can be designed arbitrarily. It is possible to use an inverted frequency band pattern that combines any one of the change patterns A to E shown in Fig. 8 with the curved pattern A or B shown in Fig. 9. The combination of the change pattern and the curved pattern is an example and is not intended to be limiting.

[0090] It is possible to use a pattern of inverted frequency bands that combines a plurality of patterns from the change patterns A to E shown in FIG.

[0091] It is possible to use a change pattern that combines a plurality of patterns from change patterns A to E shown in Fig. 8 and an inversion frequency band pattern that combines curved patterns A and / or B shown in Fig. 9. An example of this is shown in Fig. 10. The inversion frequency band pattern shown in Fig. 10 is a pattern that combines a plurality of change patterns, specifically, change pattern A, change pattern B, change pattern C, and change pattern E.

[0092] From volume adjustment value Vth to volume adjustment value V1, change pattern A is applied, and as the volume increases, the inversion frequency band is set to gradually widen from the high frequency side. From volume adjustment value V1 to volume adjustment value V2, change pattern E is applied on the high frequency side, and the inversion frequency band on the high frequency side is maintained, and change pattern B is applied on the low frequency side, and as the volume increases, the inversion frequency band is set to gradually widen from the low frequency side.

[0093] From volume adjustment value V2 to volume adjustment value V3, change pattern A is applied on the high frequency side, and as the volume increases, it is set so that the inversion frequency band on the high frequency side gradually widens, and change pattern E is applied on the low frequency side, and it is set so that the inversion frequency band on the low frequency side is maintained.

[0094] From volume adjustment value V3 to volume adjustment value V4, change pattern E is applied on the high frequency side, and the inversion frequency band on the high frequency side is maintained, and change pattern B is applied on the low frequency side, and as the volume increases, the inversion frequency band is set to gradually widen from the low frequency side.

[0095] From volume adjustment value V4 to volume adjustment value V5, change pattern A is applied on the high frequency side, and as the volume increases, it is set so that the inversion frequency band on the high frequency side gradually widens, and change pattern E is applied on the low frequency side, and it is set so that the inversion frequency band on the low frequency side is maintained.

[0096] From volume adjustment value V5 to volume adjustment value V6, change pattern E is applied on the high frequency side, and the inversion frequency band on the high frequency side is maintained, and change pattern B is applied on the low frequency side, and as the volume increases, the inversion frequency band is set to gradually widen from the low frequency side.

[0097] From the volume adjustment value V6 to the volume adjustment value Vmax, the change pattern C is applied, and as the volume increases, the inversion frequency band is set to gradually widen from the high frequency side and also to gradually widen from the low frequency side.

[0098] In this way, two or more change patterns may be used multiple times with different volume adjustment increments, so that a stepped pattern is applied. Although Fig. 10 shows an example in which only straight lines are used as curved shapes, the curved shapes of the change patterns may be different for each volume adjustment increment.

[0099] Graphs showing the relationship between volume adjustment values ​​and inversion frequencies, such as those shown in Figures 8, 9, and 10, are converted into data and stored in the form of, for example, a table in playback device 100. When performing psychological sound pressure adjustment, playback device 100 refers to the stored table and executes processing related to the psychological sound pressure adjustment.

[0100] When the frequency characteristics of the BMLD are taken into consideration with reference to Figure 2, the change pattern and curve can be designed so that the change in psychological sound pressure relative to the volume adjustment value scale is uniform by combining them while taking the following points into consideration: Figures 11 to 13 show other examples of graphs (tables) showing the relationship between the volume adjustment value and the inversion frequency.

[0101] The change patterns of the graphs shown in FIGS. 11 to 13 are designed to move toward the band near the maximum BMLD frequency or to widen from the band near the maximum BMLD frequency as the volume adjustment value increases.

[0102] The maximum BMLD frequency may vary depending on the frequency distribution of the target sound, and the frequency at which the maximum BMLD frequency is set can be set appropriately depending on the frequency distribution of the target sound. In Figures 11 to 13, an example will be described in which the band around the maximum BMLD frequency (maximum BMLD frequency band) is set to 200 Hz to 500 Hz.

[0103] Although not shown in FIG. 7, the maximum BMLD frequency is within the main range in which the BMLD effect is obtained.

[0104] The curve is designed to gradually incorporate inversion frequencies as the volume adjustment value increases in the frequency band near the maximum BMLD frequency, i.e., to have a gradual change, while the curve is designed to incorporate a wide range of inversion frequencies as the volume adjustment value increases in the high frequency band, i.e., to have a steep change. This will be explained as an example.

[0105] FIG. 11 shows a graph in the case where psychological sound pressure adjustment is performed without inverting the frequency band where the BMLD effect is most pronounced (maximum BMLD frequency band) until the end.

[0106] 11, from volume adjustment value Vth to volume adjustment value V11, change pattern A is applied, and the inversion frequency band is set so that as the volume increases, the inversion frequency band gradually widens from the high frequency side. For volume adjustment value V11, for example, the frequency from the maximum frequency of the sound signal to 500 Hz is set as the inversion frequency band.

[0107] From volume adjustment value V11 to volume adjustment value V12, change pattern E is applied to the high frequency side, and the inversion frequency band on the high frequency side is maintained, and change pattern B is applied to the low frequency side, and as the volume increases, the inversion frequency band is set to gradually widen from the low frequency side. With volume adjustment value V12, for example, the frequency from the lowest frequency of the sound signal to 200 Hz is set as the inversion frequency band.

[0108] From volume adjustment value V12 to volume adjustment value Vmax, change pattern C is applied, and as the volume increases, the inversion frequency band is set so that it gradually widens from the high frequency side (in the example of FIG. 11, it gradually widens from 500 Hz to 350 Hz) and also gradually widens from the low frequency side (in the example of FIG. 11, it gradually widens from 200 Hz to 350 Hz).

[0109] Although 200 Hz, 500 Hz, and 350 Hz have been used as examples in the above description, other frequencies may of course be used. Here, the frequency around 200 Hz, where the BMLD effect is greatest, is used as the boundary frequency, and 350 Hz has been used as an example in the description. The same applies to Figures 12 and 13 described below, and the numerical values ​​are merely examples and are not limiting.

[0110] 12 shows a graph of a case where psychological sound pressure adjustment is performed by first inverting the frequency band where the BMLD effect is strongest (maximum BMLD frequency band). Referring to FIG. 12, change pattern D is applied from volume adjustment value Vth to volume adjustment value V21. For example, as the volume increases, the inversion frequency band is set to gradually widen from approximately 350 Hz to 200 Hz (low frequency side), and also to gradually widen from approximately 350 Hz to 500 Hz (high frequency side).

[0111] From volume adjustment value V21 to volume adjustment value V22, change pattern B is applied, and the volume is set so that as the volume increases, the range gradually widens toward the high frequency side. At volume adjustment value V22, for example, the frequency from 200 Hz to the maximum frequency set as the maximum value of the inversion frequency band is set as the inversion frequency band.

[0112] From the volume adjustment value V22 to the volume adjustment value Vmax, the change pattern A is applied, and as the volume increases, the inversion frequency band is set to widen from the highest frequency set as the maximum value of the inversion frequency band to the minimum frequency set as the minimum value.

[0113] 2 and 7 again. As explained with reference to Fig. 2, the frequency band in which BMLD occurs is limited. Therefore, rather than designing a graph (table) that shows the relationship between the volume adjustment value and the inversion frequency band for the entire frequency band of the target sound, it is possible to design it only within a limited frequency range, thereby reducing the design capabilities and the amount of data stored as a table.

[0114] For example, as described with reference to Fig. 7, by treating the audible range or the main range in which the BMLD effect is obtained as an inversion frequency band, it is possible to reduce the capacity related to the design of the table and the amount of data stored in the table. Also, even when the frequency band of the sound signal is set to be treated as an inversion frequency band, it is possible to treat a range narrower than the range described with reference to Fig. 7 and thereby reduce the capacity related to the design of the table and the amount of data stored in the table.

[0115] As shown in Fig. 2, BMLD has a certain effect up to about 5 kHz, so the main range in which BMLD is effective is considered to be from 20 Hz to 5 kHz, as explained with reference to Fig. 7. Taking this into consideration, the table shown in Fig. 13 can also be created.

[0116] 13 shows a graph in which, taking into consideration the main range in which the BMLD effect is obtained, when the designated volume exceeds a volume adjustment value threshold Vth, frequencies outside the main range in which the BMLD effect is obtained are all immediately processed as inverted frequency bands. Referring to FIG. 13, when the volume adjustment value Vth is exceeded, on the high frequency side, the frequency band from 5000 Hz to the maximum frequency of the sound signal is set as the inverted frequency band, and on the low frequency side, the frequency band from the minimum frequency of the sound signal to, for example, 20 Hz is set as the inverted frequency band.

[0117] Change pattern A is applied on the high-frequency side from volume adjustment value Vth to volume adjustment value V31, and as the volume increases, the inversion frequency band is set to gradually widen from the 5000 Hz side toward the low-frequency side. At volume adjustment value V31, for example, frequencies from the maximum frequency to 500 Hz are set as the inversion frequency band. Change pattern E is applied on the low-frequency side from volume adjustment value Vth to volume adjustment value V31, and the frequency band from the minimum frequency to 20 Hz is maintained as the inversion frequency band.

[0118] Change pattern E is applied to the high frequency side from volume adjustment value V31 to volume adjustment value V32, maintaining the state in which the frequency band from the maximum frequency to 500 Hz is set as the inversion frequency band. Change pattern B is applied to the low frequency side from volume adjustment value V31 to volume adjustment value V32, setting the inversion frequency band to gradually widen from 20 Hz toward the high frequency side as the volume increases. With volume adjustment value V32, for example, frequencies from the minimum frequency to 200 Hz are set as the inversion frequency band.

[0119] From volume adjustment value V32 to volume adjustment value Vmax, change pattern C is applied, and as the volume increases, the inversion frequency band is set to gradually widen from the high frequency side (gradually widening to 350 Hz in the example of FIG. 13), and also gradually widen from the low frequency side (gradually widening to 350 Hz in the example of FIG. 13).

[0120] As explained with reference to Figure 13, by processing frequencies outside the main range in which the BMLD effect is obtained as an inverted frequency band all at once, and then applying a pattern that combines a change pattern and a curve pattern, it is possible to eliminate discontinuity in the sound signal caused by phase inversion of some frequencies.

[0121] The playback device 100 holds the graphs (tables) shown in Figures 8 to 13, and when the volume specified by the user is set to a threshold value Vth or higher, it refers to the table to set an inversion frequency band associated with the specified volume, and performs inversion processing on the signal components of the target sound in the set inversion frequency band, thereby performing psychological sound pressure adjustment.

[0122] The playback device 100 may store one or more tables. When multiple tables are stored, the playback device 100 can be configured to include a process for selecting a table to be applied depending on the type of target sound.

[0123] For example, if the target sound is determined to be a human voice, pattern D (FIG. 8) is applied, in which the frequency band of the human voice is set as the inverted frequency band. For example, if the target sound is determined to be music with a strong bass sound, pattern B is applied, in which the inverted frequency band is gradually expanded from the low frequency side to the high frequency side.

[0124] The table to be held may be editable by the user. For example, a user interface (UI) such as that shown in Fig. 14 may be presented to the user, and editing may be performed using the UI.

[0125] The UI shown in Fig. 14 is displayed, for example, on the display unit 101 of the playback device 100. An on / off setting area 12-1 for setting the hearing protection mode to on or off is displayed at the top of the UI shown in Fig. 14. The on / off setting area 12-1 displays a message saying "This is a volume adjustment function for protecting the function of the ears," and below that message a button for setting the hearing protection mode, which is a volume adjustment function for protecting the function of the ears, to on or off.

[0126] The user understands that the hearing protection mode is a volume adjustment function to protect the function of the ear, and is configured to be able to set the hearing protection mode on or off at their own will. If the hearing protection mode is set to OFF, there is a possibility that the function of the ear will not be protected, so a message is also displayed to make the user aware of the danger, such as "Listening at high volume for a long time with the hearing protection mode OFF increases the risk of damaging the function of the ear."

[0127] A channel setting area 12-2 is displayed on the lower left side of the on / off setting area 12-1. The channel setting area 12-2 displays a message such as, "You can change the channel to which signal processing related to the psychological sound pressure amplification effect (the effect of making sound easier to hear). This becomes effective when stereo headphones are connected." This channel setting area 12-2 is an area where the user can select a function channel.

[0128] The channel setting area 12-2 shown in Fig. 14 has an operation section 12-2_P1 that accepts a function channel selection operation from the user. Fig. 14 shows that the channel (Lch) corresponding to the left unit of the sound output device 50 (Fig. 15) is selected as the function channel.

[0129] The signal processing during psychological sound pressure adjustment is applied only to the sound supplied to one ear of the user, but the effect is to increase the volume of both the left and right sound signals. A channel setting area 12-2 is provided so that the channel to which the signal processing during psychological sound pressure adjustment is applied can be switched according to the user's preference.

[0130] The functional channel may be set to either the right or left and may not be changed. In such a configuration, the channel setting area 12-2 may not be provided on the UI.

[0131] An auditory characteristics measurement reception area 12-3 is provided to the lower right of the on / off setting area 12-1, and is configured to receive auditory characteristics measurement instructions from the user through the auditory characteristics measurement reception area 12-3. The auditory characteristics measurement reception area 12-3 has a start button for starting auditory characteristics measurement and a switch button for switching the auditory characteristics mode function on or off. The user can perform auditory characteristics measurement by switching the switch button to "ON" and operating the start button.

[0132] For example, a user's hearing test can be performed based on a processing module for hearing test that is pre-installed in the playback device 100. When the hearing test is performed, data on hearing characteristics can be saved for each user. A function for reading the results of a user's hearing test that was performed on a device other than the playback device 100 may be provided. When the inversion frequency band is set based on saved user hearing characteristic data, the inversion frequency band may be changed by, for example, turning on a hearing characteristic mode.

[0133] A first band setting area 12-4 is displayed at the bottom of the UI screen shown in Fig. 14. Through the first band setting area 12-4, the playback device 100 receives from the user the setting of a boundary value for separating an inverted frequency band from a non-inverted frequency band, in other words, the creation and editing of a graph (table) showing the relationship between the volume adjustment value and the inverted frequency, as described with reference to Figs. 8 to 13.

[0134] A physical sound pressure adjustment setting section 12-4_P1 is displayed above the first band setting area 12-4. The physical sound pressure adjustment setting section 12-4_P1 is configured as a slide bar (also called a slider) and is configured to accept an operation from the user to specify the volume for switching between physical sound pressure adjustment and psychological sound pressure adjustment, in other words, the volume adjustment value Vth.

[0135] The user can set the range of volume adjustment values ​​for physical sound pressure adjustment by operating the knob on the slide bar left or right. The knob position is the position of the threshold value Vth, and the user can set the maximum threshold value Vth for physically increasing the volume.

[0136] When the knob of the physical sound pressure adjustment setting unit 12-4_P1 is at the leftmost position, in other words, when the physical sound pressure adjustment is set to 0, no physical sound pressure adjustment is performed and no sound is output. To prevent this from happening, even when the knob is set to the leftmost position, a minimum value for physical sound pressure adjustment that is not 0 but a predetermined volume adjustment value is set.

[0137] When the knob of the physical sound pressure adjustment setting unit 12-4_P1 is at the rightmost position, in other words, when the volume is adjusted only by physical sound pressure adjustment and psychological sound pressure adjustment is not performed, the hearing protection mode is essentially turned off. In this way, the physical sound pressure adjustment setting unit 12-4_P1 may be configured to be able to set the hearing protection mode on and off, but the knob of the physical sound pressure adjustment setting unit 12-4_P1 may be configured not to be set further to the right than a predetermined position, and the maximum value of the physical sound pressure adjustment value that can be set may be set.

[0138] If the knob of the physical sound pressure adjustment setting section 12-4_P1 is set to the far right and psychological sound pressure adjustment is not performed, the on / off setting area 12-1 may be displayed in gray and may be made inoperable.

[0139] An inversion frequency band display area 12-4_P2 is provided below the physical sound pressure adjustment setting section 12-4_P1. The inversion frequency band display area 12-4_P2 displays the inversion frequency band that is inverted during psychological sound pressure adjustment in an area consisting of a horizontal axis indicating the volume adjustment value and a vertical axis indicating the phase inversion frequency. The inversion frequency band display area 12-4_P2 displays the graphs described with reference to FIGS. 8 to 13. The user is configured to be able to edit the shape of the curve or change the change pattern by touching and moving, for example, part of the curved portion of the displayed graph.

[0140] The inverted frequency band display area 12-4_P2 may be configured to display, for example, a recommended graph that can be edited. The recommended graph may be selected based on the type of target sound designated by the user, such as voice or music.

[0141] A second band setting area 12-5 is displayed to the right of the first band setting area 12-4 in the figure. In the second band setting area 12-5, the user can also create and edit a graph (table) showing the relationship between the volume adjustment value and the inversion frequency.

[0142] The second band setting area 12-5 has an area where the type of change pattern can be selected, for example, from a pull-down menu. The user can select a desired change pattern from the change patterns displayed in the pull-down menu and set the volume adjustment value range and which frequency bands are to be inverted for that change pattern. As long as the volume adjustment value range and the upper and lower limits of the inversion frequency of the device are not exceeded, any number of change patterns can be added by, for example, pressing the + button (displayed on the left side of the figure) in the second band setting area 12-5. A graph reflecting the settings made in the second band setting area 12-5 may be displayed in the inversion frequency band display area 12-4_P2.

[0143] The table setting unit 171 (described later with reference to FIG. 15 ) holds a preset table and / or a table set or edited by the user via the UI shown in FIG. 14 . The table setting unit 171 may automatically change the inversion frequency band as needed in accordance with the characteristics of the target sound and the characteristics of the user. For example, in the case of the voice of a specific person or the sound of a specific instrument, the table setting unit 171 may analyze the frequency power distribution in advance and set a unique volume adjustment value and inversion frequency band graph for each person or instrument.

[0144] A graph of volume adjustment values ​​and inverted frequency bands may be recommended to the user based on the frequency power distribution of the sound signal, and the user may edit the graph.

[0145] The table setting unit 171 may change the inversion frequency band from moment to moment in accordance with the frequency distribution of the target sound. In this case, the analysis results may be displayed, for example, in the first band setting area 12-4 or the second band setting area 12-5 of the UI shown in FIG. 14. The table setting unit 171 may determine the inversion frequency band of the target sound by utilizing the frequency dependency of the BMLD, for example, as described above. Note that the table setting unit 171 can determine the inversion frequency band of the target sound by utilizing the frequency dependency of the BMLD in the same way, regardless of what frequency components the target sound contains.

[0146] The table setting unit 171 may acquire data on the user's hearing characteristics by measuring the user's hearing characteristics in advance, as an example of the user's characteristics, and change the inversion frequency band as needed based on the data. Here, the user's hearing characteristics may be general-purpose or may be specific to the individual user (personal characteristics). The table setting unit 171 may manually accept the setting of the inversion frequency band from the user. In this case, the table setting unit 171 may be configured to present the power distribution of the analyzed frequency and the optimal inversion frequency band value, allowing the user to select or edit it. If the user uses a hearing aid or a sound collector, for example, data may be acquired from the user's hearing test results, audiogram, etc.

[0147] A system can be set up so that these operations can be performed online by a remote person rather than by the user themselves. For example, this service can be developed in combination with hearing aids. In the case of hearing aids, after the sound is collected by the hearing aid, sound source separation is required to separate the target sound from noise. After sound source separation, this technology can be combined as a volume adjustment function for the target sound.

[0148] For example, the graphs (tables) described above can be configured so that a remote expert can select and edit tables appropriate for the hearing aid user on behalf of the hearing aid user. This can also be used for services such as remote adjustment of hearing sensations based on the hearing characteristics of the hearing aid wearer and their changes over time. When used in the above manner, it is also possible to record the process of adjusting the volume adjustment value and inversion frequency band graph as a log, and it is also possible to edit the graphs using the log.

[0149] 14 is merely an example, and the layout of the screen and buttons is not limited to this example. For example, the setting screen (user interface) may have a voice recognition function, and instead of the user determining the selected value or recommended value of the frequency band using a slide bar or input operation, these values ​​may be determined by receiving the user's voice.

[0150] <First embodiment> Hereinafter, specific examples of each part of the playback device 100 will be described with reference to the drawings. Figures 15 and 16 are diagrams showing configuration examples of a playback device according to the first embodiment. In the description with reference to Figures 15 and 16, a case will be described in which a signal processing method is executed in which a sound signal of a target sound is band-divided in the frequency domain.

[0151] 15 and 16 includes a volume adjustment operation unit 121, a content storage unit 131, a volume control unit 132, a signal processing block 133, and a signal transmission unit 134. The signal processing block 133 includes a signal duplication determination unit 151, a band division unit 152, a signal inversion unit 153, a setting unit 154, a signal addition unit 155, and a buffer unit 156, and the setting unit 154 includes a table setting unit 171 and a channel setting unit 172.

[0152] Fig. 15 is a diagram illustrating the signal flow when the playback device 100 performs physical sound pressure adjustment, and Fig. 16 is a diagram illustrating the signal flow when the playback device 100 performs psychological sound pressure adjustment. The volume processing executed by the playback device 100 shown in Figs. 15 and 16 will be described with reference to the flowchart in Fig. 17.

[0153] In step S101, it is determined whether or not a volume operation has been performed. When the user wishes to change the volume, the user operates the volume adjustment operation unit 121. As described with reference to Fig. 5, the volume adjustment operation unit 121 is, for example, a slide bar displayed on the display unit 101 of the playback device 100, and the user sets the volume desired by operating the knob of this slide bar.

[0154] If it is determined in step S101 that the volume adjustment operation unit 121 has been operated, the process proceeds to step S102, where it is determined whether the designated volume Vcurrent has exceeded a threshold value Vth.

[0155] If it is determined in step S102 that the designated volume Vcurrent does not exceed the threshold value Vth, the process proceeds to step S103, where the signal is amplified or attenuated by physical sound pressure adjustment so that the designated volume Vcurrent is reached.

[0156] When the process in step S103 is completed, the process proceeds to step S105, where the target sound is transmitted to each channel (first signal output unit 51 and second signal output unit 52) ​​of the sound output device 50, for example, headphones.

[0157] When the process proceeds to step S103, the target sound is processed so that it becomes the designated volume Vcurrent specified by the user through physical sound pressure adjustment. The process when physical sound pressure adjustment is performed will be described again with reference to the configuration of the playback device 100 in FIG.

[0158] The table setting section 171 of the setting section 154 receives the designated volume Vcurrent from the volume adjustment operation section 121. When the table setting section 171 acquires the designated volume Vcurrent, it refers to the stored table, reads out the threshold value Vth, and supplies it to the volume control section 132. The volume control section 132 performs a process of amplifying or attenuating the sound signal by performing physical sound pressure adjustment.

[0159] The volume control unit 132 is also supplied with the designated volume Vcurrent from the volume adjustment operation unit 121 and the sound signal of the target sound from the content storage unit 131. If the volume control unit 132 determines that the designated volume Vcurrent does not exceed the threshold Vth, it performs processing to amplify or attenuate the sound signal of the target sound itself by an amount of sound pressure corresponding to the designated volume Vcurrent, and supplies the result to the signal transmission unit 134. In physical sound pressure adjustment, the target sound having the designated volume Vcurrent is generated by processing the sound signal to increase or decrease its amplitude.

[0160] The signal transmission unit 134 outputs the target sound, which has been supplied at the designated volume Vcurrent, to, for example, the first signal output unit 51 and the second signal output unit 52 of the sound output device 50. In this case, since the target sound, which has been supplied at the designated volume Vcurrent, is supplied to the signal transmission unit 134, the sound signals of the target sound supplied to the first signal output unit 51 and the second signal output unit 52 are the same sound signal.

[0161] On the other hand, if it is determined in step S102 that the designated volume Vcurrent exceeds the threshold value Vth, the process proceeds to step S104, where psychological sound pressure adjustment begins to amplify or attenuate the signal according to the designated volume Vcurrent.

[0162] Here, we will explain an example in which psychological sound pressure adjustment is initiated when the specified volume Vcurrent exceeds the threshold value Vth as an input (trigger). However, as will be described later, psychological sound pressure adjustment can also be initiated when the type of content of the sound to be processed (target sound), the volume or frequency band of the noise, etc., meets certain conditions as an input (trigger).

[0163] The process relating to psychological sound pressure adjustment executed from step S107 onwards will be described further with reference to the configuration of the playback device 100 in FIG. 16 as needed.

[0164] If the volume control unit 132 determines that the specified volume Vcurrent exceeds the threshold value Vth, it performs a process of amplifying the target sound signal itself by the amount of sound pressure corresponding to the volume that becomes the threshold value Vth, and supplies the amplified signal to the signal duplication determination unit 151 of the signal processing block 133.

[0165] In step S107, the signal duplication determination unit 151 determines whether the audio control unit target sound is a monaural signal. If it is determined in step S107 that the target sound is a monaural signal, the process proceeds to step S108. In step S108, the signal duplication determination unit 151 duplicates the sound signal of the target sound and prepares sound signals for two channels. The signal duplication determination unit 151 supplies one of the target sounds to the buffer unit 156 (step S109), and supplies the other target sound to the band division unit 152.

[0166] In step S110, the band splitting unit 152 analyzes the frequency characteristics of the sound signal by performing a Fourier transform on the sound signal acquired from the signal duplication determination unit 151. In step S111, the band splitting unit 152 refers to the table stored in the table setting unit 171, determines an inversion frequency band corresponding to the specified volume Vcurrent, and performs band splitting to divide the sound signal into inversion frequency band components and non-inversion frequency band components.

[0167] In step S112, the band splitting unit 152 generates a first sound signal by performing an inverse Fourier transform on the components of the inverted frequency band and supplies the first sound signal to the signal inversion unit 153. In step S114, the band splitting unit 152 generates a second sound signal by performing an inverse Fourier transform on the components of the non-inverted frequency band and supplies the second sound signal to the signal addition unit 155.

[0168] In step S113, the signal inversion unit 153 performs phase inversion processing to invert the phase of the first sound signal corresponding to the component of the inversion frequency band, and supplies the inverted signal after phase inversion to the signal addition unit 155. In step S115, the signal addition unit 155 generates a sum signal by adding the inverted signal acquired from the signal inversion unit 153 and the second sound signal acquired from the band division unit 152. The signal addition unit 155 supplies the generated sum signal to the signal transmission unit 134.

[0169] In step S109, the buffer unit 156 temporarily stores the sound signal acquired from the signal duplication determination unit 151 and puts the sound signal on hold until the signal addition unit 155 sends the added signal to the signal transmission unit 157.

[0170] In order for the band division unit 152 to divide the band of the sound signal in the frequency domain in real time, sufficient samples are required to analyze the frequency characteristics of the target sound. Therefore, when dividing the band of the sound signal of the target sound in the frequency domain, time is first required to accumulate sufficient samples, and time is also required to analyze the frequency characteristics in real time. Therefore, the buffer unit 156 monitors, for example, the processing status of the signal addition unit 155, and sends the temporarily stored sound signal to the signal transmission unit 157 at the timing when the signal addition unit 155 sends the added signal to the signal transmission unit 157.

[0171] In step S116, the signal transmission unit 134 acquires the added signal from the signal addition unit 155 and the sound signal from the buffer unit 156, synchronizes the acquired signals, and transmits them to the sound output device 50 through the corresponding functional channels. When supplying the sound signal to the buffer unit 156, the signal duplication determination unit 151 also supplies a non-functional channel ID, together with the sound signal, indicating whether the sound signal is for the first signal output unit 51 or the second signal output unit 52. When supplying the sound signal to the signal transmission unit 134, the buffer unit 156 also supplies the non-functional channel ID.

[0172] A function channel ID for identifying the function channel is also supplied to the signal transmitting unit 134 from the channel setting unit 172. The channel setting unit 172 sets the channel set by the user in the channel setting area 12-2 of the UI screen described with reference to FIG. 14 as the function channel, and supplies the function channel ID indicating the set function channel to the signal transmitting unit 134.

[0173] In step S105, the signal transmitting unit 134 supplies sound signals to each channel of the sound output device 50, for example, headphones. The signal transmitting unit 134 transmits the added signal acquired from the signal adding unit 155 to the first signal output unit 51 of the sound output device 50 corresponding to the function channel identified by the function channel ID, and outputs the sound signal acquired from the buffer unit 156 to the second signal output unit 52 of the sound output device 50 corresponding to the non-function channel identified by the non-function channel ID.

[0174] In step S106, it is determined whether the volume adjustment is complete, and if it is determined that it is not complete, the process returns to step S101, and the subsequent processes are repeated, and if it is determined that it is complete, the process related to the first volume process shown in Fig. 17 is terminated. For example, if the user has finished operating the volume adjustment operation unit 121, in other words, if the specified volume Vcurrent is no longer supplied, the process related to the first volume process shown in Fig. 17 is terminated.

[0175] <Second Volume Processing> The second volume processing in the playback device 100 shown in FIGS. 15 and 16 will be described with reference to the flowchart shown in FIG.

[0176] The second volume processing differs from the first volume processing in that the second volume processing is performed in the time domain. When the second volume processing is performed, the band splitting unit 152 of the playback device 100 has a function of generating a band split filter.

[0177] In the first volume processing, the band splitting unit 152 performs band splitting in the frequency domain of the sound signal, and therefore performs processing such as inverse Fourier transform in steps S112, S113, and S114. In the second volume processing, processing is performed in the time domain, and therefore the band splitting unit 152 can omit processing for handling the sound signal in the frequency domain. In the second volume processing, the processing corresponding to steps S112, S113, and S114 can be omitted.

[0178] The processing from steps S201 to S209 in the flowchart shown in FIG. 18 is the same as the processing from steps S101 to S109 in the flowchart shown in FIG. 17, and therefore a description thereof will be omitted.

[0179] In step S210, the band splitting unit 152 references the table held in the table setting unit 171, sets a frequency band corresponding to the specified volume Vcurrent, and generates a band splitting filter corresponding to the set frequency band. The band splitting unit 152 uses the generated band splitting filter to perform band splitting, which separates the sound signal into inverted frequency band components and non-inverted frequency band components. The band splitting unit 152 supplies the inverted frequency band components of the sound signal to the signal inverting unit 153, and supplies the non-inverted frequency band components to the signal adding unit 155.

[0180] In step S211, the signal inverting unit 153 performs a convolution operation using the target sound and the band splitting filter, and supplies the inverted signal after phase inversion to the signal adding unit 155. In step S212, the signal adding unit 155 generates a sum signal by adding the inverted signal acquired from the signal inverting unit 153 and the second sound signal acquired from the band splitting unit 152.

[0181] When processed in the time domain, a signal that has been subjected to the band splitting filter may have a sample shift from the original signal, that is, a sample shift may occur between the above-mentioned sum signal (the sound signal for the first signal output unit 51) and the sound signal obtained from the signal duplication determination unit 151 and held in the buffer unit 156 (the sound signal for the second signal output unit 52).

[0182] The amount of this sample shift is determined by the constructed filter, and therefore the amount of sample shift correction is known. Therefore, the signal addition unit 155 extracts and corrects the sum signal (the sound signal for the first signal output unit 51) at a certain number of samples. Alternatively, before the signal transmission unit 134 transmits the signal to the output unit, the signal addition unit 155 may be provided with a function for performing correction by extracting a section where the correlation between the sound signal for the first signal output unit 51 and the sound signal for the second signal output unit 52 is highest (the most similar).

[0183] The subsequent processing is the same as the first volume processing (FIG. 17), and therefore a description thereof will be omitted.

[0184] The first volume processing and the second volume processing (processing in the frequency domain and processing in the time domain) each have their own advantages, so they can be configured to be used selectively depending on the situation. Processing in the frequency domain has the advantage of being able to perform band division while analyzing the characteristics of the sound source. However, when processing in the frequency domain, it is divided into a phase in which samples are accumulated and a phase in which processing is performed. On the other hand, processing in the time domain has the advantage of fast time response, because processing can be performed on samples that are constantly being sent (one sample at a time).

[0185] Second Embodiment In the first embodiment, an example has been described in which the playback device 100 processes a monaural signal, but the present technology can also be applied to a playback device that processes a stereo signal. Figures 19 and 20 are diagrams showing an example configuration of a playback device 200 that processes a stereo signal.

[0186] 19 and 20 includes a volume adjustment operation unit 221, a content storage unit 231, a volume control unit 232, a signal processing block 233, and a signal transmission unit 234. The signal processing block 233 includes a signal duplication determination unit 251, a band division unit 252, a signal inversion unit 253, a setting unit 254, a signal addition unit 255, and a buffer unit 256, and the setting unit 254 includes a table setting unit 271 and a channel setting unit 272.

[0187] The configuration of the playback device 200 in the second embodiment is basically the same as the configuration of the playback device 100 in the first embodiment. Fig. 19 is a diagram illustrating the signal flow when the playback device 200 performs physical sound pressure adjustment, and Fig. 20 is a diagram illustrating the signal flow when the playback device 200 performs psychological sound pressure adjustment. With reference to Figs. 19 and 20, an explanation will be given of the processing performed by the playback device 200 when processing stereo signals that differs from that performed by the playback device 100 when processing monaural signals.

[0188] When the user performs an operation for adjusting the volume via the volume adjustment operation unit 121, the designated volume Vcurrent and the target sound stored in the content storage unit 131 are supplied to the volume control unit 132 in association with the channel ID.

[0189] When the specified volume Vcurrent is equal to or lower than the threshold value Vth, a signal flows within the playback device 200 as shown in Fig. 19, and processing for physical sound pressure adjustment is performed. The volume control unit 232 amplifies or attenuates the stereo signal of the target sound from the content storage unit 231 by an amount of sound pressure corresponding to the volume Vcurrent, and supplies the amplified or attenuated signal to the signal transmission unit 234 while maintaining the channel ID. The signal transmission unit 234 supplies the sound signal assigned with the channel ID representing the first signal output unit 51 to the first signal output unit 51, and supplies the sound signal assigned with the channel ID representing the second signal output unit 52 to the second signal output unit 52.

[0190] When the specified volume Vcurrent exceeds the threshold value Vth, a signal flows within the playback device 200, as shown in Fig. 20, and processing for psychological sound pressure adjustment is performed. The volume control unit 232 amplifies the stereo signal of the target sound from the content storage unit 231 by an amount of sound pressure corresponding to volume Vcurrent = volume Vth, and supplies the amplified signal to the signal duplication determination unit 251 while retaining the channel ID.

[0191] The signal duplication determination unit 251 receives the non-functioning channel IDs assigned to the non-functioning channels from the channel setting unit 272, supplies the sound signals corresponding to the functioning channels among the stereo signals of the target sound to the band division unit 252, and supplies the sound signals corresponding to the non-functioning channels to the buffer unit 256. At this time, the non-functioning channel IDs are also supplied to each unit together with the sound signals.

[0192] The processing performed by each of the band splitting unit 252, signal inversion unit 253, signal addition unit 255, and buffer unit 256 is similar to the processing performed by each of the band splitting unit 152, signal inversion unit 153, signal addition unit 155, and buffer unit 156 of the playback device 100 shown in Figure 16.

[0193] The signal sending unit 234 supplies a sound signal associated with a non-functional channel ID to the second signal output unit 52, which is a non-functional channel, and supplies a sound signal not associated with a non-functional channel ID to the first signal output unit 51, which is a functional channel.

[0194] Here, the reason why only the non-function channel ID is received is that information can be transmitted via a small number of blocks. The function channel ID may be received from the channel setting unit 272, and the signal may pass through the band dividing unit 252, the signal inverting unit 253, the signal adding unit 255, and the signal transmitting unit 234.

[0195] As described above, this technology can be applied whether the target sound itself is monaural or stereo. The effect of BMLD may be affected by whether the components of the target sound are allocated to the left and right channels to the same extent.

[0196] In the case of a stereo signal, the sound signal provided to the left channel is fundamentally different from the sound signal provided to the right channel. When the stereo signal is the target sound, the effect of BMLD may be reduced because the components of the target sound are not equally distributed to the left and right channels.

[0197] For example, when a song is the target sound, the vocals are often located in the center (the vocal image is in the center), and the vocal sound signal can be considered to be allocated to the left and right channels to the same extent. When such a sound containing similar signal components in the left and right channels is used as the target sound, the BMLD effect can be fully exerted even if the target sound is a stereo signal.

[0198] Even in the case of a stereo signal, it is common for the left and right channels to contain many similar signal components, so it is believed that the effects of BMLD can be fully obtained even when this technology is applied to cases where stereo signals are handled.

[0199] Furthermore, when treating a stereo signal as the target sound, the left and right signals can be analyzed, similar signal components (frequency components) can be extracted, and the frequency band containing those frequency components can be set as an inverted frequency band for processing, thereby making it easier to obtain the BMLD effect, and such a configuration is also possible.

[0200] <Third Embodiment> In the first and second embodiments, the playback devices 100 and 200 have been described with an example in which the same processing is performed regardless of the type of noise (sound that reaches the user's ears other than the target sound). The magnitude of the BMLD is affected not only by the frequency distribution of the target sound but also by the frequency distribution of the noise. Therefore, a configuration may be adopted in which the inversion frequency band is set taking into account the frequency distribution of the noise.

[0201] In the playback device 300 according to the third embodiment shown in FIG. 21, a noise detection unit 53 is provided in the sound output device 50, the frequency distribution of noise detected by the noise detection unit 53 is analyzed, and the table setting unit 371 is configured to change the graph (table) of the volume adjustment value and the inversion frequency according to the analysis result.

[0202] The table setting unit 371 receives the sound signal of the target sound from the content storage unit 331 and the sound signal of noise from the noise detection unit 53, performs frequency analysis of each sound signal, and constructs a graph (table) showing the relationship between the volume adjustment value and the inversion frequency.

[0203] The band division unit 352 extracts the target sound components within the set inversion frequency band based on the table constructed by the table setting unit 371 from the target sound, and the signal inversion unit 353 generates a sound signal by inverting the extracted target sound.

[0204] The playback device 300 has basically the same configuration as the playback devices 100 and 200 in the first and second embodiments, and performs the same processing except for the parts described above.

[0205] In this way, by setting an inversion frequency band where the BMLD effect is more likely to be obtained depending on the noise, the target sound can be made easier to hear, and even if listening at a high volume, it is possible to prevent the function of the ear from being impaired.

[0206] <Fourth Embodiment> In the first to third embodiments, an example was described in which the playback devices 100 to 300 adjust the volume based on an instruction from the user, specifically, an instruction for a volume adjustment value. Also, an example was described in which psychological sound pressure adjustment is started when the volume adjustment value instructed by the user is set to a predetermined value or higher. A mechanism may be provided in which the conditions for starting psychological sound pressure adjustment and the volume setting during psychological sound pressure adjustment are appropriately set on the playback device 100 side (hereinafter, the description will continue using the playback device 100 as an example) when certain conditions are met on the playback device 100 side.

[0207] The playback device 100 can be configured to, for example, recognize the characteristics of the content being listened to by the user, such as type and frequency distribution, and initiate psychological sound pressure adjustment based on the recognition results, and set an appropriate volume adjustment value.

[0208] The playback device 100 can be configured to, for example, recognize the characteristics of the noise in the environment in which the user is listening, such as the noise volume and frequency band, and initiate psychological sound pressure adjustment based on the recognition results, and set an appropriate volume adjustment value.

[0209] The playback device 100 can be configured to, for example, recognize both the characteristics of the content being listened to by the user and the characteristics of the noise in the listening environment, initiate psychological sound pressure adjustment based on the recognition results, and set an appropriate volume adjustment value.

[0210] <Other Graphs (Tables)> In the above-described embodiment, an example has been described in which an inverted target sound is supplied to the first signal output unit 51 of the sound output device 50, and a non-inverted target sound is supplied to the second signal output unit 52. In other words, an example has been described in which an inverted sound signal is supplied to only one channel of the sound output device 50, for example, headphones.

[0211] The sound signal for which the inversion frequency band is changed in accordance with the volume adjustment value does not have to be fixed to one channel as in the above-described embodiment, but may be configured so that the function channel is arbitrarily switched in the process of changing the volume adjustment value. An example of a graph (table) showing the relationship between the volume adjustment value and the inversion frequency band when the function channel is arbitrarily switched in the process of changing the volume adjustment value is shown in Figure 22.

[0212] Fig. 22 shows graphs in which the ranges of the inversion frequency band are different for left and right sound signals. The left diagram in Fig. 22 is a graph showing the relationship between the volume adjustment value set in the channel that provides a sound signal to the left ear (here, the first signal output unit 51) and the inversion frequency, and the right diagram in Fig. 22 is a graph showing the relationship between the volume adjustment value set in the channel that provides a sound signal to the right ear (here, the second signal output unit 52) ​​and the inversion frequency.

[0213] From the volume adjustment value Vth to the volume adjustment value Vchange, the sound signal provided to the left ear channel is inverted, and the sound signal provided to the right ear channel is not inverted. Referring to the left diagram of Figure 22, from the volume adjustment value Vth to the volume adjustment value Vchange, change pattern A (Figure 8) is applied, and the band is gradually widened from the high frequency side to the low frequency side. At the volume adjustment value Vchange, the frequencies from the maximum frequency of the inversion frequency band to the frequency Fcut are set as the inversion frequency band.

[0214] When focusing on components with a frequency equal to or higher than Fcut between the volume adjustment value Vth and the volume adjustment value Vchange, the first sound signal provided to the first signal output unit 51 (left ear) is inverted, and the second sound signal provided to the second signal output unit 52 (right ear) is not inverted, so the first signal and the second sound signal are in an anti-phase relationship, thereby achieving the effect of BMLD.

[0215] When the volume adjustment value is from the volume adjustment value Vchange to the volume adjustment value Vmax, for frequencies above the frequency Fcut, the sound signal provided to the left ear channel is inverted and the sound signal provided to the right ear channel is not inverted, and for frequencies below the frequency Fcut, the sound signal provided to the left ear channel is not inverted and the sound signal provided to the right ear channel is inverted.

[0216] Referring to the left diagram in Figure 22, pattern E (Figure 8) is applied from volume adjustment value Vchange to volume adjustment value Vmax, the frequency band from the maximum frequency of the inversion frequency band to frequency Fcut is set as the inversion frequency band, and that inversion frequency band is maintained.

[0217] 22, pattern B (FIG. 8) is applied from volume adjustment value Vchange to volume adjustment value Vmax, and the band is gradually widened from the minimum frequency of the inversion frequency band toward the higher frequency side. At volume adjustment value Vmax, the frequencies from the minimum frequency of the inversion frequency band to frequency Fcut are set as the inversion frequency band.

[0218] When focusing on components with a frequency equal to or higher than Fcut between the volume adjustment value Vchange and the volume adjustment value Vmax, the sound signal provided to the first signal output unit 51 (left ear) and the sound signal provided to the second signal output unit 52 (right ear) are in an anti-phase relationship, so the BMLD effect can be obtained for sound components with a frequency equal to or higher than Fcut.

[0219] When focusing on components with a frequency equal to or lower than Fcut between the volume adjustment value Vchange and the volume adjustment value Vmax, the sound signal provided to the first signal output unit 51 (left ear) and the sound signal provided to the second signal output unit 52 (right ear) are in an opposite phase relationship, so the BMLD effect can be obtained even for sound components with a frequency equal to or lower than Fcut.

[0220] In this way, with a predetermined frequency Fcut as the boundary, the left ear signal is set to a frequency range above Fcut, and the right ear signal is set to a frequency range below Fcut for phase inversion, and it is possible to design which of the left and right sound signals is to be inverted and in what frequency range depending on the operation of the volume adjustment operation unit 121.

[0221] The graph (table) shown in FIG. 22 is an example, and the graph when the range of the inversion frequency band is presented so as to be different for the left and right sound signals is not limited to the graph shown in FIG. 22, and other graphs can also be applied.

[0222] For example, a graph (table) may be used in which pattern C (FIG. 8) is applied, and the upper half of pattern C shown in FIG. 8 is applied to the sound signal supplied to the first signal output unit 51, and the lower half of pattern C shown in FIG. 8 is applied to the sound signal supplied to the second signal output unit 52.

[0223] According to this technology, the inversion frequency band to which BMLD is applied is gradually changed based on the set volume adjustment value, making it possible to psychologically sense an increase or decrease in volume, and to set a volume feeling that suits the user's preferences while avoiding the risk of damage to ear function.

[0224] For example, this technology can be applied to playback devices used in situations where you want to hear sounds through headphones at the same time, such as when communicating face-to-face, in other words actively listening to sounds around you, while also contacting a remote person through headphones or listening to music coming from headphones as background music, and can be more effective in such situations as well.

[0225] <Regarding the Recording Medium> The above-described series of processes can be executed by hardware or software. When the series of processes is executed by software, the programs that make up the software are installed on a computer. Here, the term "computer" includes computers built into dedicated hardware, and general-purpose personal computers, for example, that can execute various functions by installing various programs.

[0226] 23 is a block diagram showing an example of the hardware configuration of a computer that executes the above-mentioned series of processes using a program. In the computer, a CPU (Central Processing Unit) 2001, a ROM (Read Only Memory) 2002, and a RAM (Random Access Memory) 2003 are interconnected by a bus 2004. An input / output interface 2005 is also connected to the bus 2004. An input unit 2006, an output unit 2007, a storage unit 2008, a communication unit 2009, and a drive 2010 are connected to the input / output interface 2005.

[0227] The input unit 2006 includes a keyboard, a mouse, a microphone, etc. The output unit 2007 includes a display, a speaker, etc. The storage unit 2008 includes a hard disk, a nonvolatile memory, etc. The communication unit 2009 includes a network interface, etc. The drive 2010 drives removable media 2011 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.

[0228] In a computer configured as described above, the CPU 2001 performs the above-described series of processes by, for example, loading a program stored in the memory unit 2008 into the RAM 2003 via the input / output interface 2005 and the bus 2004 and executing it.

[0229] The program executed by the computer (CPU 2001) can be provided by being recorded on, for example, a removable medium 2011 such as a package medium. The program can be provided via a wired or wireless transmission medium such as a local area network, the Internet, or digital satellite broadcasting.

[0230] In the computer, the program can be installed in the storage unit 2008 via the input / output interface 2005 by inserting the removable medium 2011 into the drive 2010. The program can be received by the communication unit 2009 via a wired or wireless transmission medium and installed in the storage unit 2008. Alternatively, the program can be installed in advance in the ROM 2002 or the storage unit 2008.

[0231] The program executed by the computer may be a program that processes in chronological order according to the order described in this specification, or may be a program that processes in parallel or at the required timing, such as when called.

[0232] In this specification, a system refers to an entire device made up of multiple devices.

[0233] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0234] It should be noted that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the present technology.

[0235] The present technology can also be configured as follows. (1) An information processing device including: a setting unit that sets a partial band of a band of a processing target sound as an inverted frequency band and another band as a non-inverted frequency band; and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the processing target sound before processing, wherein the setting unit changes the partial band in response to a predetermined input. (2) The information processing device described in (1), wherein the predetermined input is a setting of a volume adjustment value. (3) The information processing device described in (1) or (2), wherein the predetermined input is a type of content of the processing target sound or noise. (4) The information processing device described in any of (1) to (3), wherein the setting unit sets the inverted frequency band when the volume adjustment value is set to a predetermined value or higher. (5) The information processing device described in any of (1) to (4), wherein the setting unit sets the inverted frequency band so as to widen as the volume adjustment value increases. (6) The information processing device according to (5), wherein the inversion frequency band is gradually widened from the high frequency side to the low frequency side as the volume adjustment value increases. (7) The information processing device according to (5), wherein the inversion frequency band is gradually widened from the low frequency side to the high frequency side as the volume adjustment value increases. (8) The information processing device according to (5), wherein the inversion frequency band is gradually widened from the high frequency side to the low frequency side and from the low frequency side to the high frequency side as the volume adjustment value increases. (9) The information processing device according to (5), wherein the inversion frequency band is gradually widened from a predetermined frequency to the high frequency side and then to the low frequency side as the volume adjustment value increases.(10) The information processing device according to any of (1) to (4), wherein the inversion frequency band corresponding to the setting of the volume adjustment value is set according to a pattern that combines at least two or more of: a first pattern that gradually widens the inversion frequency band from high frequencies to low frequencies as the volume adjustment value increases, a second pattern that gradually widens the inversion frequency band from low frequencies to high frequencies, a third pattern that gradually widens the inversion frequency band from high frequencies to low frequencies and from low frequencies to high frequencies, a fourth pattern that widens the inversion frequency band from a predetermined frequency to high frequencies and then to low frequencies, and a fifth pattern that maintains a predetermined inversion frequency band. (11) The information processing device according to (10), wherein the setting unit selects one of the first to fifth patterns according to characteristics of the processing target sound or noise, and sets the inversion frequency band associated with the volume adjustment value. (12) The information processing device according to (11), wherein the characteristics are a frequency distribution or a type of the processing target sound or the noise. (13) The information processing device according to any one of (1) to (12), further comprising an increase unit that increases the amplitude of the signal of the processing target sound in accordance with a set volume adjustment value until the volume adjustment value is set to a predetermined value or greater. (14) The information processing device according to any one of (1) to (13), further comprising a duplication unit that duplicates the monaural signal when the processing target sound is a monaural signal. (15) The information processing device according to any one of (1) to (14), wherein the setting unit sets the band of the processing target sound into the inverted frequency band and the non-inverted frequency band in the frequency domain or the time domain. (16) The information processing device according to any one of (1) to (15), wherein the setting unit sets the inverted frequency band that includes frequency components included in both the left and right processing target sounds when the processing target sound is a stereo signal. (17) The information processing device according to any one of (1) to (16), wherein the range of the inverted frequency band differs between a first sound signal provided to a first channel and a second sound signal provided to a second channel.(18) An information processing method for processing sound, comprising: a setting unit; and an output unit; wherein the setting unit sets a portion of a band of a sound to be processed as an inverted frequency band and another portion as a non-inverted frequency band; the output unit outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band, in synchronization with the sound to be processed before processing; and the setting unit includes processing for changing the portion of the band in accordance with a predetermined input. (19) A program for causing a computer to function as: a setting unit that sets a part of the band of a sound to be processed as an inverted frequency band and the other bands as a non-inverted frequency band; and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, wherein the setting unit includes a function to change the part of the band in response to a predetermined input.

[0236] 50 Sound output device, 51 First signal output unit, 52 Second signal output unit, 53 Noise detection unit, 100 Playback device, 101 Display unit, 121 Volume adjustment operation unit, 131 Content storage unit, 132 Volume control unit, 133 Signal processing block, 134 Signal transmission unit, 151 Signal duplication determination unit, 152 Band division unit, 153 Signal inversion unit, 154 Setting unit, 155 Signal addition unit, 156 Buffer unit, 157 Signal transmission unit, 171 Table setting unit, 172 Channel setting unit, 200 Playback device, 221 Volume adjustment operation unit, 231 Content storage unit, 232 Volume control unit, 233 Signal processing block, 234 Signal transmission unit, 251 Signal duplication determination unit, 252 Band division unit 253 Signal inversion unit, 254 Setting unit, 255 Signal addition unit, 256 Buffer unit, 271 Table setting unit, 272 Channel setting unit, 300 Playback device, 331 Content storage unit, 352 Band division unit, 353 Signal inversion unit, 371 Table setting unit

Claims

1. An information processing device comprising: a setting unit that sets some bands of a band of a sound to be processed as inverted frequency bands and other bands as non-inverted frequency bands; and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, wherein the setting unit changes the some bands in response to a predetermined input.

2. The information processing device according to claim 1, wherein the predetermined input is a setting of a volume adjustment value.

3. The information processing device according to claim 1, wherein the predetermined input is a type of content of the sound to be processed or noise.

4. The information processing device according to claim 1, wherein the setting unit sets the inverted frequency band when the volume adjustment value is set to a predetermined value or higher.

5. The information processing device according to claim 1, wherein the setting unit sets the inversion frequency band so as to widen as the volume adjustment value increases.

6. The information processing device according to claim 5, wherein the inverted frequency band is gradually widened from the high frequency side to the low frequency side as the volume adjustment value increases.

7. The information processing device according to claim 5, wherein the inverted frequency band is gradually widened from the low frequency side to the high frequency side as the volume adjustment value increases.

8. The information processing device according to claim 5, wherein the inverted frequency band is gradually widened from the high frequency side to the low frequency side and from the low frequency side to the high frequency side as the volume adjustment value increases.

9. The information processing device according to claim 5, wherein the inverted frequency band is gradually widened from a predetermined frequency toward the high frequency side and toward the low frequency side as the volume adjustment value increases.

10. The information processing device of claim 1, wherein the inversion frequency band corresponding to the setting of the volume adjustment value is set according to a pattern that combines at least two of the following patterns: a first pattern that gradually widens the inversion frequency band from the high frequency side to the low frequency side as the volume adjustment value increases; a second pattern that gradually widens the inversion frequency band from the low frequency side to the high frequency side; a third pattern that gradually widens the inversion frequency band from the high frequency side to the low frequency side and from the low frequency side to the high frequency side; a fourth pattern that widens the inversion frequency band from a predetermined frequency to the high frequency side and back to the low frequency side; and a fifth pattern that maintains a predetermined inversion frequency band.

11. The information processing device according to claim 10, wherein the setting unit selects one of the first to fifth patterns according to the characteristics of the target sound or noise, and sets the inversion frequency band associated with the volume adjustment value.

12. The information processing device according to claim 11, wherein the characteristics are the frequency distribution or type of the target sound or noise.

13. The information processing device according to claim 1, further comprising an increase unit that increases the amplitude of the signal of the sound to be processed in accordance with the volume adjustment value that has been set until the volume adjustment value is set to a predetermined value or greater.

14. The information processing device according to claim 1, further comprising a duplication unit that duplicates the monaural signal when the sound to be processed is a monaural signal.

15. The information processing device according to claim 1, wherein the setting unit sets the band of the sound to be processed to the inverted frequency band and the non-inverted frequency band in the frequency domain or the time domain.

16. The information processing device according to claim 1, wherein, when the target sound is a stereo signal, the setting unit sets the inverted frequency band including frequency components contained in both the left and right target sounds.

17. The information processing device according to claim 1, wherein the range of the inverted frequency band differs between the first sound signal provided to the first channel and the second sound signal provided to the second channel.

18. An information processing method for processing sound, comprising: a setting unit; and an output unit; wherein the setting unit sets some bands of the band of the sound to be processed as inverted frequency bands and other bands as non-inverted frequency bands; the output unit outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band, in synchronization with the sound to be processed before processing; and the setting unit includes processing for changing the some bands in accordance with a predetermined input.

19. A program for causing a computer to function as: a setting unit that sets some bands of a sound to be processed as inverted frequency bands and other bands as non-inverted frequency bands; and an output unit that outputs an added signal obtained by adding an inverted signal obtained by inverting the phase difference of a first signal sound corresponding to the inverted frequency band and a second signal sound corresponding to the non-inverted frequency band in synchronization with the sound to be processed before processing, wherein the setting unit includes a function to change the some bands in response to a predetermined input.

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