Processing device, sound system, and method for producing precedence effect

Abstract

To use a lead signal to create a precedence effect.SOLUTION: A disclosed processing device may be a processing device that generates a leading sound and a following sound that is delayed with respect to the leading sound to create a leading sound effect for the leading sound. The processing device may be configured to generate, as the leading sound, a first radiation signal including a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the following sound to create a leading sound effect for the leading sound, and may be a signal with a frequency that is substantially inaudible to a listener.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a processing device, an audio system, and a method for producing a precedence effect. [Background technology]

[0002] Patent Document 1 discloses guiding evacuees using the Haas effect, also known as the precedence effect. The precedence effect is a phenomenon in which, when similar sounds arrive at a listener from different directions with a slight time difference, the listener perceives a sound image in the direction of the sound that arrived first. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-134660 Summary of the Invention

[0004] This disclosure proposes a new method for the precedence effect, in which a leading signal is placed before a main signal to be heard, to generate the precedence effect.

[0005] One aspect of the present disclosure is a processing device. The disclosed processing device may be a processing device that generates a leading sound and a following sound that is delayed with respect to the leading sound to create a leading sound effect for the leading sound. The processing device may be configured to generate, as the leading sound, a first radiation signal including a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the following sound to create a leading sound effect for the leading sound, and may be a signal with a frequency that is substantially inaudible to a listener.

[0006] Another aspect of the present disclosure is an audio system. The disclosed audio system may include a processing device that generates a leading sound and a following sound that is delayed relative to the leading sound to create a leading sound effect for the leading sound, and a speaker device that radiates the leading sound and the following sound. The processing device may be configured to generate, as the leading sound, a first radiation signal that includes a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the following sound to create a leading sound effect for the leading sound, and may be a virtual signal at a frequency that is substantially inaudible to a listener.

[0007] Another aspect of the present disclosure is a method. The disclosed method may be a method for generating a precedence effect. The disclosed method may include emitting a first radiated signal as the precedence sound, the first radiated signal including a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the following sound to generate a precedence effect for the preceding sound, and may be a signal of a frequency that is substantially inaudible to a listener.

[0008] Further details will be described in the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of an acoustic system. [Figure 2] FIG. 2 is an explanatory diagram of a radiation signal. [Figure 3] FIG. 3 is an explanatory diagram of a radiation signal. [Figure 4] FIG. 4 is a flowchart of sound image control. [Figure 5] FIG. 5 shows a table showing the experimental results. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. Overview of the Processing Device, Sound System, and Method for Producing Precedence Effect

[0011] (1) A processing device according to an embodiment may be a processing device that generates a leading sound and a following sound that is delayed relative to the leading sound to create a leading sound effect for the leading sound. The processing device may be configured to generate, as the leading sound, a first radiation signal including a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the following sound to create a leading sound effect for the leading sound, and may be a signal with a frequency that is substantially inaudible to a listener.

[0012] The first lead signal, which precedes the following sound, can create a precedence effect. Moreover, since the first lead signal is a signal with a frequency that is practically inaudible to the listener, the influence on the content of the signal can be reduced.

[0013] (2) The processing device may be configured to generate, as the following sound, a second radiation signal comprising a second main signal for listening and a second lead signal arranged before the second main signal to create a precedence effect on the preceding sound. The second lead signal may be a signal delayed with respect to the first lead signal and may be a signal of a frequency that is substantially inaudible to a listener.

[0014] (3) The first main signal and the second main signal may have a first time difference. The first read signal and the second read signal may have a second time difference that is different from the first time difference.

[0015] (4) The first and second main signals do not need to have a time difference, but the first and second read signals may have a time difference.

[0016] (5) The first read signal may be a signal having a frequency of 15 kHz or higher.

[0017] (6) The time length of the first read signal may be shorter than that of the first main signal.

[0018] (7) An acoustic system according to an embodiment may include a processing device that generates a leading sound and a following sound that is delayed relative to the leading sound to create a leading sound effect for the leading sound, and a speaker device that radiates the leading sound and the following sound. The processing device may be configured to generate, as the leading sound, a first radiation signal that includes a first main signal for listening and a first lead signal that is placed before the first main signal. The first lead signal is a signal that precedes the following sound to create a leading sound effect for the leading sound, and may be a virtual signal with a frequency that is substantially inaudible to a listener.

[0019] (8) A method according to an embodiment may be a method for generating a precedence effect for a preceding sound that precedes a subsequent sound. The method according to an embodiment may include emitting, as the preceding sound, a first radiation signal including a first main signal for listening and a first lead signal arranged before the first main signal. The first lead signal may be a signal that precedes the subsequent sound so as to generate a precedence effect for the preceding sound, and may be a signal with a frequency that is substantially inaudible to a listener.

[0020] <2. Examples of Processing Devices, Sound Systems, and Methods for Producing Precedence Effects>

[0021] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

[0022] 1 shows an acoustic system 10 according to an embodiment. The acoustic system 10 of the embodiment controls a sound image by utilizing the precedence effect. A conventional sound image control method using the precedence effect is a method of controlling the position of a sound image by appropriately delaying the emission of sound from multiple speakers.

[0023] In contrast to this, in the embodiment, in order to generate a precedence effect, a lead signal for generating the precedence effect is added before the main signal heard by the listener 100. The lead signal precedes the following sound and generates the precedence effect. A very short time is sufficient for the lead signal. The lead signal realizes sound image control such as sound image localization or sound image localization emphasis of the main signal.

[0024] Since the main signal is intended for listening to the listener 100, it is preferable that the main signal be a signal in a frequency band that is relatively easy for the listener 100 to hear. On the other hand, the lead signal is preferably a signal in a frequency band that is substantially inaudible to the listener, in order to prevent the lead signal from affecting the listener's ability to hear the content of the main signal.

[0025] The frequency band that is substantially inaudible to the listener is, for example, the ultrasonic frequency band or a relatively high frequency band (difficult-to-hear band) among the audible frequency bands. The inventor has confirmed through experiments that a lead signal can produce a precedence effect even if the lead signal is a sound with a frequency that is substantially inaudible to the listener. A lead signal with a frequency band that is substantially inaudible to the listener is also called a "virtual lead signal." By using a virtual lead signal, it is possible to produce a precedence effect in the main signal while avoiding affecting the audibility of the content of the main signal for listening.

[0026] Here, ultrasonic waves refer to sounds in the frequency band of 20 kHz and above. Note that sound is an elastic wave that propagates through air (medium).

[0027] Humans cannot hear ultrasound. Therefore, the frequency band of 20 kHz or higher is (part of) the frequency band that listeners cannot substantially hear. As mentioned above, the frequency band of ultrasound is 20 kHz or higher (lower limit). There is no particular upper limit to the frequency band of ultrasound, but from a practical point of view, the upper limit may be, for example, 100 kHz or lower, 1 MHz or lower, 10 MHz or lower, 100 MHz or lower, or 1 GHz or lower.

[0028] Additionally, audible sound refers to sound in the frequency band from 20 Hz to less than 20 kHz. Therefore, the frequency band of audible sound is from 20 Hz to less than 20 kHz.

[0029] Audible sounds are generally considered to be sounds that humans can hear. However, in reality, humans cannot hear all sounds in the audible sound frequency band. In many cases, even within the audible sound frequency band, it is difficult to hear sounds with frequencies above 18 kHz, and in some cases even sounds with frequencies of around 15 kHz are difficult to hear. Therefore, the frequency band that listeners cannot substantially hear includes not only the ultrasonic frequency band but also relatively high frequency bands within the audible sound frequency band (difficult-to-hear bands). Sounds in the difficult-to-hear band can also be used as lead signals. Here, the difficult-to-hear band is defined as being between 15 kHz and 20 kHz. The difficult-to-hear band is preferably between 18 kHz and 20 kHz, and more preferably between 19 kHz and 20 kHz.

[0030] The acoustic system 10 of the embodiment emits a radiation signal that becomes a leading sound and a radiation signal that becomes a following sound to generate a precedence effect at the listener 100. The leading sound is a sound that precedes the following sound. The leading sound arrives at the listener 100 slightly before the following sound, causing the listener 100 to perceive the arrival direction of the leading sound as the direction of a sound image due to the precedence effect. The following sound is a sound that is slightly delayed from the leading sound and is the same as or similar to the leading sound. Examples of similar sounds include sounds from each channel in stereo sound or surround sound. The following sound arrives at the listener 100 from a different direction from the leading sound. Due to the precedence effect, the arrival direction of the following sound is not perceived as the direction of a sound image. Details of the leading sound and following sound according to the embodiment will be described later.

[0031] 1 includes a processing device 20 that generates a signal of radiated sound (radiation signal), and a speaker device 30 that radiates the generated radiation signal into space. The sound radiated from the speaker device 30 can be heard by a listener 100. Note that the speaker device 30 according to the embodiment has a characteristic that can radiate signals in the audible sound frequency band and the ultrasonic frequency band, for example.

[0032] The speaker device 30 shown in FIG. 1 is, for example, a stereo speaker. The stereo speaker includes a first speaker 30L for a left channel (L channel) and a second speaker 30R for a right channel (R channel). The first speaker 30L emits sound for the left channel, and the second speaker 30R emits sound for the right channel. Note that the speaker device 30 is not limited to a stereo speaker, and it is sufficient if it includes multiple speakers. The speaker device 30 may be, for example, a surround speaker, or may simply include a large number of multiple speakers.

[0033] In FIG. 1, it is assumed that the listener 100 is located at an equal distance from the first speaker 30L and the second speaker 30R.

[0034] The processing device 20 performs signal processing (sound image control) to generate a signal to be emitted by the speaker device 30. The processing device 20 may be configured, for example, by a computer that executes signal processing defined by software, or by a hardware circuit that performs signal processing.

[0035] The processing device 20 shown in FIG. 1 generates, as an example, a first radiation signal s for the left channel. L (t) and the second radiation signal s for the right channel R (t) and generate.

[0036] 2 and 3 show the first radiation signal s L (t) and the second radiation signal s R Here, as an example, the second radiation signal s R (t) is the total of the first radiation signal s L (t) for τ lagvl (See Figure 3.) Therefore, the first radiation signal s L (t) arrives at the listener 100 as a preceding sound and is the second emitted signal s R (t) is a small time difference τ lagvl Therefore, due to the precedence effect, the first radiation signal s LThe direction of arrival of (t) (to the left) is perceived as the direction of the sound image by the listener 100. In other words, the sound image is localized to the left.

[0037] First radiation signal s L (t) and the second radiation signal s R (t) with a time difference τ lagvl To generate a first radiation signal s L (t) and the second radiation signal s R 2 and 3, different delay amounts are applied to the first radiation signal s L (t) contains the delay τ vlL is added, and the second radiation signal s R (t) contains the delay τ vlL Delay amount τ greater than vlR delay is given.

[0038] Time difference τ lagvl is the time difference that can produce the precedence effect. lagvl is, for example, about 1 ms to 100 ms, and more preferably about 1 ms to 10 ms. lagvl may be set to 2 ms, as an example.

[0039] First radiation signal s L (t) is the first lead signal (preceding lead signal) s Vl (t-τ vlL ) and the first read signal s Vl (t-τ vlL ) followed by the first signal s m (t-τ mL ) and the first signal s m (t-τ mL ) is the first read signal s Vl (t-τ vlL ) with an interval τ durL (See FIG. 3). durL may be zero. durL The interval τ can be, for example, about 0 ms to 10 ms. durLThe first read signal s may be about 0 ms to 5 ms, or about 0 ms to 3 ms. Vl (t-τ vlL ) is the first signal s m (t-τ mL ) may overlap in time. In this case, the interval τ durL does not exist.

[0040] First read signal s Vl (t-τ vlL ) time length τ lengVl The first read signal s (see FIG. 3) is not particularly limited, but may be very short, for example, about 1 ms to 10 ms. Vl (t-τ vlL ) time length τ lengVl is the first signal s m (t-τ mL ) time length τ lengm (See FIG. 3) The first read signal s Vl (t-τ vlL ) time length τ lengVl The first read signal s may be about 1 ms to 5 ms, or may be about 1 ms to 3 ms. Vl (t-τ vlL ) time length τ lengVl is the first signal s m (t-τ mL ) time length τ lengm It may be longer.

[0041] First signal s m (t-τ mL ) time length τ lengm (see FIG. 3) is not particularly limited, but may be, for example, 15 ms or less. m (t-τ mL ) time length τ lengm The shorter the lead signal, the easier it is to create a precedence effect with the virtual lead signal. m (t-τ mL ) time length τ lengm may be 12 ms or less.

[0042] Second radiation signal s R (t) is also the first radiation signal s L (t), i.e., the second radiation signal s R (t) is the second read signal (subsequent read signal) s Vl (t-τ vlR ) and the second read signal s Vl (t-τ vlR ) followed by the second signal s m (t-τ mR ) and.

[0043] However, the second radiation signal s R (t) is the second read signal s Vl (t-τ vlR In this case, the second radiation signal s R (t) is the second signal s m (t-τ mR ) is sufficient, and the second signal s m (t-τ mR ) is the first radiation signal s L The second radiation signal s without a lead signal is delayed from (t). R (t) is the first radiation signal s having the lead signal L Although it is not identical to (t), if the signal as a whole is similar, it may produce a precedence effect.

[0044] Second signal s m (t-τ mR ) is the second read signal s Vl (t-τ vlR ) with an interval τ durR (See FIG. 3). durR may be zero. durR The interval τ can be, for example, about 0 ms to 10 ms. durR The second read signal s may be about 0 ms to 5 ms, or about 0 ms to 3 ms. Vl (t-τ vlR ) is the second signal s m (t-τ mR ) may overlap in time. In this case, the interval τ durRdoes not exist.

[0045] Second read signal s Vl (t-τ vlR ) time length τ lengVl (See Figure 3) is the first read signal s Vl (t-τ vlL ) time length τ lengVl The second read signal s may be the same as, or may be slightly different from, the second read signal s Vl (t-τ vlR ) time length τ lengVl (See FIG. 3) may be, for example, about 1 ms to 10 ms. Vl (t-τ vlR ) time length τ lengVl is the second signal s m (t-τ mR ) time length τ lengm (See Figure 3) The second read signal s Vl (t-τ vlR ) time length τ lengVl The second read signal s may be about 1 ms to 5 ms, or about 1 ms to 3 ms. Vl (t-τ vlR ) time length τ lengVl is the second signal s m (t-τ mR ) time length τ lengm It may be longer.

[0046] Second read signal s Vl (t-τ vlR ) is the first read signal s Vl (t-τ vlL ) for τ lagvl The time difference between the two read signals is τ lagvl The second time difference (τ) creates a precedence effect in the main signal following the lead signal. lagvl is, for example, about 1 ms to 100 ms, and more preferably about 1 ms to 10 ms. lagvl may be set to 2 ms, as an example.

[0047] Second signal s m (t-τmR ) time length τ lengm (See Figure 3) is the first signal s m (t-τ mL ) time length τ lengm (see Figure 3), but may be slightly different.

[0048] Second signal s m (t-τ mR ) is the first signal s m (t-τ mL ) for τ lagm The first time difference between the two signals is τ lagm (the first time difference) produces a binaural effect in the signal. To produce a binaural effect, the first time difference τ lagm is, for example, approximately 0.5 ms at most. The binaural effect is when the listener 100 hears sound with both ears and perceives the direction or position of the sound, or the size of the space, from the difference in the arrival times of the sounds perceived by each ear. Due to the binaural effect, the sound image moves in the direction of the sound (main signal) that was emitted earlier.

[0049] First time difference τ lagm The first time difference τ of the main signals of both channels can be determined by the time difference depending on the direction of the sound image localization. lagm By controlling the time difference τ between the two channels, the direction of the sound image perceived by the listener 100 can be controlled by the binaural effect. lagm The presence of this effect allows the binaural effect to enhance the precedence effect described above. The combination of the precedence effect and the binaural effect realizes emphasis on sound image localization.

[0050] First time difference τ of this signal lagm and the second time difference τ of the read signal lagvl and may be different. Therefore, the first time difference τ lagm is set to an appropriate value taking into account the binaural effect, and the second time difference τ lagvl may be set to another appropriate value taking into account the precedence effect.

[0051] In addition, the first time difference τlagm When the binaural effect is not used, the first time difference τ lagm may be zero. That is, the first and second signals may not have a time difference. Even in this case, the second time difference τ lagvl If there is such a sound, the sound image can be localized in the direction from which the preceding sound comes by using the precedence effect of the lead signal.

[0052] Also, the interval τ durL and interval τ durR If is zero, the first signal s m (t-τ mL ) and the second signal s m (t-τ mR ) and the time difference τ lagm is the first read signal s Vl (t-τ vlL ) and the first lead signal s Vl (t-τ vlL ) and the time difference τ lagvl can be equal to

[0053] However, the interval τ durL and interval τ durR Even if is zero, by making the lengths of the first read signal and the second read signal different, the first signal s m (t-τ mL ) and the second signal s m (t-τ mR ) and the time difference τ lagm to produce a binaural effect.

[0054] An example of a method for generating the radiation signals shown in FIGS. 2 and 3 (a method for controlling a sound image) will be described below with reference to FIGS.

[0055] As shown in Fig. 4, the acoustic system 10 performs sound image direction control on the main signal (step S41). m (t) is given to the signal delay processing unit 21. The signal delay processing unit 21 includes a first signal delay processing unit 21L for the left channel and a second signal delay processing unit 21R for the right channel.

[0056] The first main signal delay processing unit 21L delays the main signal s m (t) with a delay of τ mL The first signal s m (t-τ mL The second main signal delay processing unit 21R generates the main signal s m (t) with a delay of τ mR The second signal s m (t-τ mR ) is generated. Due to the binaural effect, the first signal s m (t-τ mL ), the delay amount τ mL The delay amount τ mR Conversely, the second signal s m (t-τ mR ) direction, the delay amount τ mL The delay amount τ mR 2 and 3, the first signal precedes the second signal.

[0057] As shown in Fig. 4, in step S42, the acoustic system 10 executes a process of adding a virtual lead signal to the main signal (sound image localization emphasis control). Vl (t) is given to the read signal delay processing unit 22. The read signal delay processing unit 22 includes a first read signal delay processing unit 22L for the left channel and a second read signal delay processing unit 22R for the right channel.

[0058] The first read signal delay processing unit 22L delays the read signal s vl (t) with a delay of τ vlL The first read signal s V1 (t-τ vlL ) to generate the first read signal s V1 (t-τ vlL ) is added to the first signal s m (t-τ mL) and the first radiation signal s L (t) (see equation (1) in Figure 1) is generated. L (t) is emitted as a leading sound by the speaker 30L.

[0059] The second read signal delay processing unit 22R delays the read signal s vl (t) with a delay of τ vlR delay is applied, and the second read signal s V1 (t-τ vlR ) to generate the second read signal s V1 (t-τ vlR ) is added to the second signal s m (t-τ mR ) and the second radiation signal s R (t) (see equation (2) in Figure 1) is generated. R (t) is emitted as a subsequent sound by the speaker 30R.

[0060] FIG. 5 shows the results of an experiment using the acoustic system 10 shown in FIG. 1. In the experiment, two types of signals were used as lead signals: white noise of 20 kHz to 21 kHz (conditions in FIG. 5: WN) and a sine wave of 40 kHz (conditions in FIG. 5: Sin). Here, τ vlL = 2ms and τ vlR = 0ms, and the second read signal s of the right channel vl When preceded by τ vlL = 0ms and τ vlR = 2ms, the first read signal s of the left channel vl Experiments were conducted on the cases where the first step was preceded by the second step.

[0061] τ mL ,τ mR Regarding the above, the front of the listener 100 was defined as 0°, the left direction was defined as positive, and the time difference calculated from the interaural time difference corresponding to each of the sound image directions θ = -20°, -10°, 0°, 10°, and 20° of the signal to be presented was set.

[0062] In the experiment, the listener 100 was asked to subjectively evaluate whether the sound image perceived by the listener 100 was in one of three patterns: "moved to the left," "moved to the right," or "did not move" due to the lead signal. The answer was considered correct if the direction of the preceding lead signal and the direction of movement of the sound image perceived by the listener 100 matched. The percentage of correct answers was calculated for each condition. Figure 5 shows the results.

[0063] The correct answer rates for both the WN and Sin conditions exceeded 33%, which is the expected value when options are chosen randomly. Therefore, it was confirmed that sound image localization or sound image localization enhancement is possible using the lead signal.

[0064] In addition, for the WN condition, when the sound image presentation direction of this signal was 0°, the correct answer rate was lower compared to when the sound image was presented in other directions. This is thought to be because the discrimination limit of human hearing is narrower in the front than in the lateral direction, so the correct answer rate was lower compared to other directions.

[0065] The present invention is not limited to the above-described embodiment, and various modifications are possible. [Explanation of symbols]

[0066] 10: Sound system 20: Processing equipment 21: This signal delay processing unit 21L: First signal delay processing section 21R: Second signal delay processing section 22: Read signal delay processing section 22L: First read signal delay processing section 22R: Second read signal delay processing section 23L: First adder 23R: Second addition unit 30: Speaker device 30L: 1st speaker 30R: 2nd speaker 100: Listener

Claims

1. 1. A processing device that generates a preceding sound and a following sound that is delayed with respect to the preceding sound to cause a preceding sound effect to the preceding sound, The first signal for listening, a first lead signal disposed before the first main signal; and generating a first radiation signal as the preceding sound, the first radiation signal comprising: The first lead signal is a signal that precedes the following sound so as to produce a precedence effect on the preceding sound, and is a signal with a frequency that is substantially inaudible to a listener. Processing equipment.

2. The processing device includes: A second signal for listening, a second lead signal disposed before the second main signal to generate a precedence effect for the preceding sound; as the subsequent sound, The second read signal is a signal delayed with respect to the first read signal and has a frequency that is substantially inaudible to a listener. The processing device of claim 1 .

3. the first signal and the second signal have a first time difference; The first read signal and the second read signal have a second time difference that is different from the first time difference. The processing device according to claim 2 .

4. the first signal and the second signal have no time difference; The first read signal and the second read signal have a time difference. The processing device of claim 2 .

5. The first read signal is a signal having a frequency of 15 kHz or more. The processing device of claim 1 .

6. The time length of the first read signal is shorter than that of the first main signal. The processing device of claim 1 .

7. a processor that generates a preceding sound and a following sound that is delayed relative to the preceding sound to create a preceding sound effect for the preceding sound; a speaker device that radiates the preceding sound and the following sound; Equipped with The processing device includes: The first signal for listening, a first lead signal disposed before the first main signal; and generating a first radiation signal as the preceding sound, the first radiation signal comprising: The first lead signal is a signal that precedes the following sound so as to produce a precedence effect on the preceding sound, and is a virtual signal of a frequency that is substantially inaudible to a listener. Sound system.

8. A method for generating a precedence effect on a preceding sound that precedes a subsequent sound, comprising: radiating a first radiation signal as the preceding sound, the first radiation signal comprising a first main signal for listening and a first lead signal arranged before the first main signal; the first lead signal is a signal that precedes the subsequent sound so as to cause a precedence effect on the preceding sound, and is a signal with a frequency that is substantially inaudible to a listener; A method for creating a precedence effect.

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