Sound signal processing method and sound signal processing device

Abstract

To provide a sound signal processing method capable of maintaining the breadth of music without disturbing other sounds such as conversation even when volume is operated.SOLUTION: A sound signal processing method inputs an audio signal, filters the audio signal to generate a sound field effect signal that generates a sound field effect, controls a first gain of the audio signal, controls a second gain of the sound field effect signal, accepts a volume operation, and adjusts the first gain or the second gain in conjunction with the volume operation to adjust the level balance between the audio signal and the sound field effect signal, and when a volume operation is accepted in the volume operation, increases or decreases at least the first gain, and outputs the gain-controlled audio signal and the gain-controlled sound field effect signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a sound signal processing method and a sound signal processing device. [Background technology]

[0002] Patent Document 1 describes a sound image localization device that simplifies the processing when localizing a sound image and improves operability. The sound image localization device of Patent Document 1 has a main parameter window that includes a direct sound mute button. When the direct sound mute button is clicked, the direct sound is muted and direct sound, including primary reflected sound from the floor, is cut. When the direct sound mute button is clicked while the sound image localization device of Patent Document 1 is in the mute-on state, the direct sound mute-on state is canceled. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-140199 Summary of the Invention [Problem to be solved by the invention]

[0004] When listening to music and wanting to hear other sounds such as conversations, you can turn down the volume of the music using the volume control to make it easier to hear the other sounds such as conversations. However, turning down the volume using the volume control makes it harder to hear the music.

[0005] An object of one embodiment of the present invention is to provide a sound signal processing method that can maintain the spaciousness of music without interfering with other sounds such as music and conversations, even when volume is operated. [Means for solving the problem]

[0006] A sound signal processing method according to one embodiment of the present invention inputs an audio signal, filters the audio signal to generate a sound field effect signal that generates a sound field effect, controls a first gain of the audio signal, controls a second gain of the sound field effect signal, accepts a volume operation, and adjusts the first gain or the second gain in conjunction with the volume operation to adjust the level balance between the audio signal and the sound field effect signal, and when a volume operation is accepted in the volume operation, increases or decreases at least the first gain, and outputs the gain-controlled audio signal and the gain-controlled sound field effect signal. [Effects of the Invention]

[0007] According to the sound signal processing method of one embodiment of the present invention, even when the volume is adjusted, the spaciousness of the music can be maintained without interfering with other sounds such as conversations, allowing you to enjoy music at any time in a variety of situations and environments. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing the configuration of a sound signal processing device 1. FIG. [Figure 2] 2 is a block diagram showing a functional configuration of a signal processing unit 12 of the present embodiment or modified example 1. FIG. [Figure 3] 3 is a flowchart showing the operation of a sound signal processing method performed by the sound signal processing device 1. [Figure 4] FIG. 10 is a block diagram showing a functional configuration of a signal processing unit 12 according to a second modification. [Figure 5] FIG. 11 is a block diagram showing a functional configuration of a signal processing unit 12 according to a third modification. [Figure 6] FIG. 11 is a block diagram showing a functional configuration of a signal processing unit 12 according to a fourth modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 is a block diagram showing the configuration of a sound signal processing device 1. The sound signal processing device 1 includes an input unit 11, a signal processing unit 12, an output unit 13, a user interface (I / F) 14, a flash memory 15, a RAM 16, and a CPU 17.

[0010] The sound signal processing device 1 is an information processing device such as a personal computer (PC), a smartphone, an audio receiver, or a set-top box.

[0011] The input unit 11 has an interface such as HDMI (registered trademark), etc. The input unit 11 receives audio data from a player, etc., and outputs the data to the signal processing unit 12.

[0012] The signal processing unit 12 is made up of, for example, a DSP, and decodes the input audio data to extract an audio signal and performs various signal processing on the audio signal under the control of the CPU 17. In this embodiment, all audio signals will be described as digital audio signals unless otherwise specified.

[0013] The output unit 13 outputs the audio signal after signal processing by the signal processing unit 12. The output unit 13 outputs the audio signal to an acoustic device such as a speaker or a headphone. The output unit 13 may include a D / A converter and an amplifier. The output unit 13 may convert the audio signal into an analog audio signal, amplify it, and then output it to an acoustic device such as a speaker.

[0014] The user I / F 14 includes at least a volume operator. The user I / F 14 accepts a volume operation from a user. Alternatively, the user I / F 14 may accept the volume operation via a user terminal such as a smartphone. The sound signal processing device 1 changes the audio level signal in response to the volume operation. Alternatively, the sound signal processing device 1 changes the amplification factor of the amplifier in response to the volume operator.

[0015] The flash memory 15 is an example of a storage medium, and stores the operating program (firmware) of the sound signal processing device 1.

[0016] The RAM 16 functions as a work memory for the CPU 17. The CPU 17 reads out the operation programs stored in the flash memory 15 into the RAM 16, thereby controlling the sound signal processing device 1 in an overall manner.

[0017] 2 is a block diagram showing the functional configuration of the signal processing unit 12. The signal processing unit 12 functionally includes a decoder 131, a first gain control unit 132, a sound field effect signal generation unit 133, a second gain control unit 134, an adjustment unit 135, and an adder 136.

[0018] The decoder 131 decodes the content data to extract an audio signal, and inputs the extracted audio signal to a first gain control unit 132 and a sound field effect signal generation unit 133.

[0019] The first gain control section 132 controls the first gain of the input audio signal and outputs the result to the adder 136 .

[0020] The sound field effect signal generation unit 133 performs filtering on the input audio signal to generate a sound field effect signal. Filtering is a process of generating simulated reflected sound that simulates the reverberation (reflected sound) of a certain room, for example, by adding a predetermined delay time to the input audio signal and adjusting the level. Alternatively, filtering may be a process of convolving a predetermined impulse response with the input audio signal. The impulse response is configured using an FIR filter that reproduces the reflected sound of, for example, a concert hall, a stadium, or a live music venue. The sound field effect signal corresponds to the indirect sound component when the audio signal is considered to be the direct sound component. As a result, the sound field effect signal reproduces the reverberation in a certain acoustic space, such as a concert hall, to generate a sound field effect.

[0021] The second gain control section 134 controls the second gain of the sound field effect signal and outputs it to the adder 136 .

[0022] The adder 136 mixes the audio signal output from the first gain control section 132 with the sound field effect signal output from the second gain control section 134 and outputs the result to the output section 13.

[0023] The output unit 13 outputs the audio signal and the sound field effect signal mixed by the adder 136. The output unit 13 outputs the audio signal and the sound field effect signal to an acoustic device such as a speaker or a headphone.

[0024] A listener listens to sounds based on audio signals, which are direct sound components, and sound based on sound field effect signals, which are indirect sound components, via acoustic equipment such as speakers or headphones.

[0025] The adjustment unit 135 adjusts the first gain or the second gain in conjunction with a volume operation received from the user I / F 14, thereby adjusting the level balance between the audio signal and the sound field effect signal.

[0026] 3 is a flowchart showing the operation of the sound signal processing method performed by the sound signal processing device 1. As described above, the sound field effect signal generation unit 133 receives audio as input (S11) and performs filter processing on the audio signal to generate a sound field effect signal that produces a sound field effect (S12).

[0027] The adjustment unit 135 adjusts the first gain or the second gain in conjunction with the volume operation (S13). Here, when the adjustment unit 135 receives a volume decrease operation, it decreases at least the first gain to adjust the level balance between the audio signal and the sound field effect signal.

[0028] The first gain control section 132 and the second gain control section 134 control the levels of the audio signal and the sound field effect signal using the first gain and the second gain adjusted by the adjustment section 135, respectively, and output them to the adder 136 (S14).

[0029] The adder 136 mixes the audio signal controlled by the first gain control unit 132 and the sound field effect signal controlled by the second gain control unit 134 (S15). The output unit 13 outputs the audio signal and the sound field effect signal mixed by the adder 136 (S16).

[0030] For example, when a user wants to hear other sounds, such as conversation, while listening to content such as music, the user turns down the volume to make the other sounds, such as conversation, easier to hear. However, simply lowering the level of the audio signal by turning down the volume reduces the overall volume of the content, making it difficult to listen to the content.

[0031] However, the sound signal processing method of this embodiment reduces at least the first gain in response to a volume reduction operation, adjusting the level balance between the audio signal and the sound field effect signal to suppress a decrease in the perceived volume of the entire content. More specifically, the perceived volume of the audio signal, which is a direct sound component, decreases, but the perceived volume of the sound field effect signal, which is an indirect sound component, is maintained. Therefore, the sound signal processing method of this embodiment can maintain the spaciousness of the music. On the other hand, since the indirect sound component has a lower sense of localization than the direct sound component, maintaining the perceived volume of the indirect sound component does not interfere with hearing other sounds, such as conversation, which have a sense of localization. The sound signal processing method of this embodiment reduces the perceived volume of the audio signal, which is a direct sound component, in response to a volume reduction operation, making the position of the music perceived as being farther away from the user. In other words, the sound signal processing method of this embodiment is a method for controlling the distance between the user and the music by operating the volume.

[0032] As described above, when a user of the signal processing method of this embodiment wants to hear other sounds such as conversations while listening to content such as music, even if the user turns down the volume, the sound of the music can be maintained without being disturbed by the other sounds such as conversations. This allows for a new customer experience of being able to enjoy music at any time in a variety of situations and environments.

[0033] Note that changing the level balance includes setting the first gain to 0. Even if the first gain is set to 0 and the direct sound component is muted, the breadth of the music can be maintained. Also, the adjustment unit 135 may decrease the first gain while maintaining the second gain. In this case, the same breadth of the music can be maintained.

[0034] Note that the adjustment unit 135 may return to a state where the user can concentrate on listening to content such as music by, for example, increasing the first gain when the volume is increased again. This allows the adjustment unit 135 to easily return to a state where the user can concentrate on listening to content such as music.

[0035] (Variation 1) 2 is a block diagram showing the functional configuration of the signal processing unit 12 according to Modification 1. When a volume decrease operation is received in the volume operation, the adjustment unit 135 of the signal processing unit 12 according to Modification 1 adjusts both the first gain and the second gain. More specifically, when a volume decrease operation is received in the volume operation, both the first gain and the second gain are decreased. However, the amount of decrease in the first gain is greater than the amount of decrease in the second gain.

[0036] In Modification 1, when the user increases the amount of volume reduction, the levels of both the direct sound component and the indirect sound component decrease significantly, reducing the perceived volume of the entire content. However, when the amount of volume reduction is small, the decrease in perceived volume due to the sound field effect signal, which is an indirect sound component, is small. Therefore, in Modification 1, when the amount of volume reduction is small, the breadth of the music can be maintained. On the other hand, when the amount of volume reduction is large, the perceived volume of the entire content, including the indirect sound component, decreases, reducing the perceived breadth of the music. This allows the user to hear other sounds such as conversations while listening to content such as music by slightly lowering the volume. The sound signal processing method of this embodiment is a method for controlling the spread of music by operating the volume.

[0037] (Variation 2) 4 is a block diagram showing the functional configuration of the signal processing unit 12 according to Modification 2. The adjustment unit 135 of the signal processing unit 12 according to Modification 2 further adjusts the parameters of the filter processing of the sound field effect signal generation unit 133 in conjunction with the volume operation.

[0038] For example, the adjustment unit 135 increases the delay time of the indirect sound component in response to the volume reduction operation, or changes the filter coefficient of the FIR filter in response to the volume reduction operation to change the impulse response to a larger acoustic space.

[0039] In this way, in variant 2, by increasing the spread of the music in response to the volume reduction operation, the user perceives the sound of the content as coming from farther away, and the sense of localization becomes lower, so that it does not interfere with hearing other sounds such as conversations that have a sense of localization.

[0040] (Variation 3) 5 is a block diagram showing a functional configuration of the signal processing unit 12 according to Modification 3. The first gain control unit 132 of the signal processing unit 12 according to Modification 2 includes a low-pass filter 171. The low-pass filter 171 performs low-pass filtering as an example of predetermined signal processing on the audio signal.

[0041] The adjustment unit 135 adjusts the parameters of the low-pass filter processing in conjunction with the volume operation. The low-pass filter processing is a process for reducing the gain of the high frequency range of the audio signal, and is an example of controlling the first gain. That is, the adjustment unit 135 controls the first gain by adjusting the parameters of the low-pass filter processing in conjunction with the volume operation.

[0042] The frequency characteristics in the high frequency range affect the localization of sound. In Modification 3, the gain of the high frequency range of the audio signal is reduced by low-pass filtering. In Modification 3, the localization of the audio signal, which is the direct sound component, is reduced by low-pass filtering, so that other sounds, such as conversations, which have a localized sound, are not impeded from being heard.

[0043] Note that the filtering is not limited to low-pass filtering. Filtering also includes other signal processing such as band-pass filtering, high-pass filtering, compression, limiting, or equalization. The first gain control unit 132 performs predetermined signal processing on the audio signal, and the adjustment unit 135 adjusts a predetermined signal parameter of the first gain control unit 132 in conjunction with a volume operation. Similarly to the first gain control unit 132, the second gain control unit 134 may also include a low-pass filter.

[0044] (Variation 4) FIG. 6 is a block diagram showing the functional configuration of the signal processing unit 12 according to Modification 4. The sound signal processing device 1 according to Modification 4 further includes a microphone 18. The adjustment unit 135 of Modification 4 further changes the level balance between the audio signal and the sound field effect signal according to the user's listening environment. The user's listening environment is detected using the microphone 18, which is an example of a sensor. The user's listening environment includes, for example, whether or not there is a person near the user, whether or not a specific sound (a meaningful sound such as an announcement, an alarm, or a telephone call) is ringing, or whether or not there is a conversation. The adjustment unit 135 determines whether or not there is a person near the user, whether or not a specific sound is ringing, or whether or not there is a conversation, based on the sound signal acquired by the microphone 18.

[0045] When there is a person near the user, when a specific sound is being generated, or when there is conversation, the adjustment unit 135 adjusts the level balance between the audio signal and the sound field effect signal by adjusting the first gain or the second gain in conjunction with the volume operation.When there is no person near the user, when a specific sound is not being generated, or when there is no conversation, the adjustment unit 135 does not adjust the level balance between the audio signal and the sound field effect signal, and changes the volume of the entire content in accordance with the volume operation.

[0046] As a result, in an environment where the user can concentrate on listening to content such as music, the volume of the entire content is linked to the volume operation, and in an environment where the user listens to content such as music while also hearing other sounds such as conversation, the volume of the direct sound component is lowered in conjunction with the volume operation. Therefore, in Modification 4, it is possible to achieve appropriate sound signal processing according to the user's listening environment.

[0047] Furthermore, adjustment unit 135 may return the user to a state where the user can concentrate on listening to content such as music by increasing the first gain when it determines that there is no one near the user, that a specific sound is not being played, or that there is no conversation, etc. In this way, adjustment unit 135 can easily return the user to a state where the user can concentrate on listening to content such as music.

[0048] The above-described embodiments and modifications should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above-described embodiments or modifications, but by the claims. Furthermore, the scope of the present invention is intended to include all modifications that are equivalent to and within the scope of the claims. [Explanation of symbols]

[0049] 1: Sound signal processing device, 11: Input unit, 12: Signal processing unit, 13: Output unit, 14: User I / F, 15: Flash memory, 16: RAM, 17: CPU, 131: Decoder, 132: First gain control unit, 133: Sound field effect signal generation unit, 134: Second gain control unit, 135: Adjustment unit, 136: Adder, 171: Low-pass filter

Claims

1. An audio signal is input, and a sound field effect signal for producing a sound field effect is generated by filtering the audio signal; controlling a first gain of the audio signal; Controlling a second gain of the sound field effect signal; Accepts volume control, adjusting the first gain or the second gain in conjunction with the volume operation to adjust a level balance between the audio signal and the sound field effect signal, and increasing or decreasing at least the first gain when a volume operation is received in the volume operation; outputting the gain-controlled audio signal and the gain-controlled sound field effect signal; Sound signal processing method.

2. When a volume decrease operation is received in the volume operation, the first gain is decreased while the second gain is maintained. The sound signal processing method according to claim 1 .

3. When a volume decrease operation is received in the volume operation, both the first gain and the second gain are adjusted; The amount of decrease in the first gain is greater than the amount of decrease in the second gain. The sound signal processing method according to claim 1 .

4. changing the level balance includes setting the first gain to 0; The sound signal processing method according to claim 1 .

5. adjusting a parameter of the filtering process for generating the sound field effect signal in conjunction with the volume operation; The sound signal processing method according to any one of claims 1 to 4.

6. the control of the first gain includes performing predetermined signal processing on the audio signal; controlling the first gain by adjusting the predetermined signal processing parameter for controlling the first gain in conjunction with the volume operation; The sound signal processing method according to any one of claims 1 to 4.

7. the predetermined signal processing includes low-pass filtering, a parameter of the low-pass filter processing is adjusted in conjunction with the volume operation to control the first gain; The sound signal processing method according to claim 6.

8. and changing the level balance between the audio signal and the sound field effect signal in accordance with the listening environment of the user. The sound signal processing method according to any one of claims 1 to 4.

9. a sound field effect signal generating unit that receives an audio signal and filters the audio signal to generate a sound field effect signal that produces a sound field effect; a first gain control unit that controls a first gain of the audio signal; a second gain control unit that controls a second gain of the sound field effect signal; a reception unit that receives a volume operation; an adjustment unit that adjusts the first gain or the second gain in conjunction with the volume operation to adjust a level balance between the audio signal and the sound field effect signal, and that increases or decreases at least the first gain when a volume operation is received in the volume operation; an output unit that outputs the audio signal gain-controlled by the first gain control unit and the sound field effect signal gain-controlled by the second gain control unit; A sound signal processing device comprising:

10. When a volume decrease operation is received in the volume operation, the adjustment unit decreases the first gain while maintaining the second gain. The sound signal processing device according to claim 9 .

11. the adjustment unit adjusts both the first gain and the second gain when a volume decrease operation is received in the volume operation; The amount of decrease in the first gain is greater than the amount of decrease in the second gain. The sound signal processing device according to claim 9 .

12. changing the level balance includes setting the first gain to 0; The sound signal processing device according to claim 9 .

13. the adjustment unit adjusts the filter processing parameters of the sound field effect signal generation unit in conjunction with the volume operation. The sound signal processing device according to any one of claims 9 to 12.

14. the first gain control unit performs predetermined signal processing on the audio signal; the adjustment unit controls the first gain by adjusting a parameter of the predetermined signal processing of the first gain control unit in conjunction with the volume operation. The sound signal processing device according to any one of claims 9 to 12.

15. the predetermined signal processing includes low-pass filtering, the adjustment unit controls the first gain by adjusting a parameter of the low-pass filter processing in conjunction with the volume operation. The sound signal processing device according to claim 14 .

16. the adjustment unit further changes the level balance between the audio signal and the sound field effect signal in accordance with a user's listening environment. The sound signal processing device according to any one of claims 9 to 12.

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