JP2021048553A - Fundamental tone frequency determination device, pseudo low-pitched sound processor, method for determining frequency of fundamental tone, and method for acoustic processing - Google Patents

Abstract

To provide a fundamental tone frequency determination device that can easily determine the frequency of a fundamental tone when pseudo low-pitched sound processing is conducted.SOLUTION: A fundamental tone frequency determination device 1 is for determining a fundamental tone frequency FF when pseudo low-pitched sound processing is conducted on an acoustic input signal s1. The device includes: an acquisition unit 10 for acquiring the lowest resonance frequency F0 of a sound output device 3, on which the pseudo low-pitched sound processing is to be conducted; and a determination unit 11 for determining the fundamental tone frequency FF on the basis of the lowest resonance frequency F0.SELECTED DRAWING: Figure 2

Description

The present disclosure discloses a fundamental frequency determining device for determining a fundamental frequency when performing pseudo-bass processing on an acoustic input signal, a fundamental frequency determining method, a pseudo-bass processing device for performing pseudo-bass processing using the fundamental frequency, and a pseudo-bass processing device for performing pseudo-bass processing using the fundamental frequency. , Regarding the sound processing method.

A frequency equalizer is widely used to enhance the bass component of the sound output from the speaker. By operating the frequency equalizer, the user can intuitively set which frequency band of the bass components is amplified and how much. However, the frequency equalizer cannot enhance the frequency component that cannot be reproduced by the speaker, that is, the frequency component lower than the minimum resonance frequency of the speaker.

As a technique for enhancing a frequency component that cannot be reproduced by a speaker, a pseudo-bass processing technique using an auditory psychological phenomenon called a missing fundamental phenomenon is known (see, for example, Patent Document 1). In the missing fundamental phenomenon, even if the fundamental tone is missing, if the overtone group component (for example, when the fundamental tone is 50 Hz, the overtone group component is 100 Hz, 150 Hz, 200 Hz, etc.) is present, the missing fundamental tone is audibly heard. It is a phenomenon of hearing. In an acoustic processing system using this pseudo-bass processing technology, the harmonic group component of the fundamental frequency is added to the acoustic input signal and output, so even if the speaker cannot reproduce the frequency component that is the fundamental tone, the user You can hear the sound including the fundamental frequency.

Japanese Patent No. 4286510

However, if the engineer developing the speaker is not familiar with the pseudo-bass processing technology, it may be difficult to determine the fundamental frequency when performing the pseudo-bass processing.

The present disclosure has been made in view of such a problem, and provides a fundamental frequency determining device and the like capable of easily determining the fundamental frequency when performing pseudo-bass processing on an acoustic input signal. The purpose.

The fundamental frequency determining device in the present disclosure is a fundamental frequency determining device that determines the fundamental frequency when performing pseudo-bass processing on an acoustic input signal, and determines the lowest resonance frequency of the sound output device that is the target of performing the pseudo-bass processing. It includes an acquisition unit for acquisition and a determination unit for determining the fundamental frequency based on the lowest resonance frequency.

The pseudo bass processing device in the present disclosure is a pseudo bass processing device that performs pseudo bass processing on an acoustic input signal, and is a fundamental frequency determining device according to any one of claims 1 to 6 from the acoustic input signal. It includes a bandpass filter that extracts and outputs a signal of the determined fundamental frequency, and a harmonic generation unit that generates a harmonic group component of the signal output from the bandpass filter.

The pseudo-bass processing device in the present disclosure is a pseudo-bass processing device that performs pseudo-bass processing on an acoustic input signal, and is a fundamental frequency determining device according to any one of claims 3 to 6 from the acoustic input signal. At least a bandpass filter that extracts and outputs a signal of the determined fundamental frequency, a harmonic generation unit that generates a harmonic group component of the signal output from the bandpass filter, and a signal generated by the harmonic generation unit. It includes a low boost filter that amplifies with the amplification amount.

The fundamental frequency determination method in the present disclosure is a method of determining the fundamental frequency when performing pseudo-bass processing on an acoustic input signal, and is a step of acquiring the lowest resonance frequency of the sound output device to which the pseudo-bass processing is performed. And the step of determining the fundamental frequency based on the lowest resonance frequency.

The acoustic processing method in the present disclosure is an acoustic processing method that performs pseudo-bass processing on an acoustic input signal, and includes a step of acquiring the minimum resonance frequency of a sound output device to be subjected to the pseudo-bass processing, and the minimum resonance frequency. The step of determining the fundamental frequency in the pseudo-bass processing based on the above, the step of extracting the signal of the fundamental frequency from the acoustic input signal, and the step of extracting the signal of the fundamental frequency from the signal of the fundamental frequency to generate the signal of the harmonic group component of the fundamental frequency. The step of adding the signal of the harmonic group component to the acoustic input signal is included.

It should be noted that these comprehensive or specific embodiments may be implemented in a system, method, integrated circuit, computer program or computer-readable recording medium such as a CD-ROM, system, method, integrated circuit, computer. It may be realized by any combination of a program and a recording medium.

According to the fundamental frequency determining device and the like of the present disclosure, it is possible to easily determine the fundamental frequency when performing pseudo-bass processing on the acoustic input signal.

It is a figure which shows an example of the pseudo bass processing apparatus. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in Embodiment 1. FIG. It is a figure which shows the minimum resonance frequency of the sound output device which is the object of performing pseudo-bass processing, and the fundamental frequency at the time of performing pseudo-bass processing. It is a flowchart which shows the fundamental frequency determination method and sound processing method of Embodiment 1. It is a figure which shows an example of the hardware composition of the computer which realizes the function of the fundamental frequency determination apparatus of Embodiment 1 by software. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in the modification of Embodiment 1. FIG. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in Embodiment 2. It is a figure which shows the minimum resonance frequency, the attenuation characteristic, and the fundamental frequency at the time of performing pseudo bass processing of a sound output device. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in the modification of Embodiment 2. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in Embodiment 3. It is a block diagram which shows the structure of the fundamental frequency determination apparatus and the pseudo bass processing apparatus in the modification of Embodiment 3.

(Background to this disclosure)
While there are many sound output devices such as speakers and earphones in the world, it is expected that the number of cases where each manufacturer developing the sound output device adjusts the sound quality of the sound output device will increase in the future. When the above-mentioned pseudo-bass processing is introduced as one of the cases for adjusting the sound quality of the sound output device, it is considered that the pseudo-bass processing device 102 as shown below is used.

FIG. 1 is a diagram showing an example of a pseudo bass processing device 102. FIG. 1 also shows a sound output device 3 such as a speaker connected to the pseudo bass processing device 102.

The pseudo bass processing device 102 shown in FIG. 1 includes a bandpass filter 23 that extracts the fundamental frequency from the acoustic input signal s1, a harmonic generation unit 24 that generates harmonic group components of the signal output from the bandpass filter 23, and a harmonic generation. The addition unit 28 that adds the harmonic signal sh generated by the unit 24 to the acoustic input signal s1 is provided. In this pseudo bass processing device 102, since the harmonic group component of the fundamental frequency is added to the acoustic input signal s1 and output, the user can hear the sound including the fundamental frequency.

In order to realize such pseudo bass processing, it is necessary to set and input the fundamental frequency to the bandpass filter 23 in advance. However, if the engineer who is developing the sound output device 3 is not familiar with the pseudo-bass processing technique, it is difficult to determine the fundamental frequency when performing the pseudo-bass processing. On the other hand, it is considered that the engineer of the sound output device 3 fully understands the physical characteristics of the sound output device 3, such as the resonance frequency characteristic.

Therefore, the present disclosure provides a fundamental frequency determining device and the like that can easily determine the fundamental frequency by using the physical characteristics of the sound output device 3 and the like.

Hereinafter, embodiments will be specifically described with reference to the drawings. It should be noted that all of the embodiments described below show a specific example of the present disclosure. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, the components not described in the independent claims indicating the implementation embodiment according to the present disclosure will be described as arbitrary components. The embodiment of the present disclosure is not limited to the current independent claims, but may be expressed by other independent claims.

It should be noted that each figure is a schematic view and is not necessarily exactly shown. Further, in each figure, substantially the same configuration is designated by the same reference numerals, and duplicate description may be omitted or simplified.

(Embodiment 1)
[1-1. Configuration of fundamental frequency determination device and pseudo bass processing device]
The configuration of the fundamental frequency determining device and the pseudo bass processing device according to the first embodiment will be described with reference to FIGS. 2 and 3.

FIG. 2 is a block diagram showing the configurations of the fundamental frequency determining device 1 and the pseudo bass processing device 2 according to the first embodiment. FIG. 2 also shows a sound output device 3 connected to the pseudo bass processing device 2. Further, FIG. 2 also shows an acoustic processing system 5 composed of a fundamental frequency determining device 1, a pseudo bass processing device 2, and a sound output device 3.

The sound output device 3 is a device that converts the acoustic output signal s2 output from the pseudo bass processing device 2 into sound and outputs it, and is, for example, a sound output unit of a speaker or a headphone. The sound output device 3 is a device to which pseudo-bass processing is performed in the present embodiment. For example, sound in a frequency band of 90 Hz or higher can be output, but sound in a frequency band lower than 90 Hz is gradually attenuated. It has a structure to do. Therefore, the sound quality is adjusted by pseudo-bass processing for the sound output device 3.

Hereinafter, the fundamental frequency determining device 1 and the pseudo bass processing device 2 will be described in order.

The fundamental frequency determining device 1 is a device that determines the fundamental frequency FF, and is, for example, a personal computer in which a program for determining the fundamental frequency FF is installed.

As shown in FIG. 2, the fundamental frequency determination device 1 includes an acquisition unit 10 that acquires the lowest resonance frequency F0 of the sound output device 3, a determination unit 11 that determines the fundamental frequency FF, and a BPF that generates a bandpass filter coefficient. (Bandpass filter) A coefficient generation unit 12 is provided.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 of the sound output device 3. The lowest resonance frequency F0 is input to the acquisition unit 10 by, for example, an engineer of the sound output device 3 who knows the physical characteristics of the sound output device 3.

FIG. 3 is a diagram showing the lowest resonance frequency F0 of the sound output device 3 to be subjected to the pseudo bass processing and the fundamental frequency FF when the pseudo bass processing is performed. The solid line in FIG. 3 is an actually measured value of the resonance frequency characteristic of the sound output device 3, and the thick broken line is a linear approximation of this resonance frequency characteristic.

The lowest resonance frequency F0 is the frequency at which the signal output begins to be attenuated in the low band in terms of the frequency characteristics of the sound output device 3. The lowest resonance frequency F0 is an eigenvalue of the sound output device 3, and can take various values depending on the size and material of the sound output device 3. The lowest resonance frequency F0 of the sound output device 3 in this embodiment is 90 Hz. The resonance frequency characteristic is attenuated with a constant gradient in a frequency band lower than the lowest resonance frequency F0.

The determination unit 11 is a calculation unit that determines the fundamental frequency FF based on the lowest resonance frequency F0 acquired by the acquisition unit 10. The determination unit 11 of the present embodiment determines a frequency that is 1/2 of the lowest resonance frequency F0 as the fundamental frequency. In the fundamental frequency determination device 1, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11.

FIG. 3 shows that the lowest resonance frequency F0 is 90 Hz and the fundamental frequency FF is 45 Hz. In the above, the value of 1/2 of the lowest resonance frequency F0 is determined as the fundamental frequency FF, but this value is not always exact. For example, if the sound output device 3 can reproduce the frequency component of the second harmonic of the fundamental frequency FF, the fundamental frequency FF is not limited to 1/2 of the lowest resonance frequency F0, but is a value of 3/8 or more and 5/8 or less. It may be.

The BPF coefficient generation unit 12 is a calculation unit that generates the filter coefficient of the bandpass filter 23, which will be described later, based on the fundamental frequency FF determined by the determination unit 11. This filter coefficient can be calculated by a known method. The filter coefficient is generated so that the fundamental frequency FF becomes the center frequency of the bandpass filter 23. However, the filter coefficient does not necessarily have to be generated so that the fundamental frequency FF becomes the center frequency of the bandpass filter 23, and the fundamental frequency FF may be generated so as to be included in the half price width of the bandpass filter 23. ..

The filter coefficient generated by the BPF coefficient generation unit 12 is output to the pseudo bass processing device 2. The filter coefficient may be output to the pseudo-bass processing device 2 via a recording medium such as a USB memory, or the pseudo-bass processing is performed by directly connecting the fundamental frequency determining device 1 and the pseudo-bass processing device 2. It may be output to the device 2.

The pseudo bass processing device 2 is, for example, a device built into a speaker or a headphone. The pseudo bass processing device 2 performs pseudo bass processing on the acoustic input signal s1 and outputs the sound to the sound output device 3. The acoustic input signal s1 is branched after being input to the pseudo bass processing device 2, one of the branched acoustic input signals s1 is output to the adder 28, and the other acoustic input signal s1 is output to the bandpass filter 23. Will be done.

As shown in FIG. 2, the pseudo bass processing device 2 includes a storage unit 21, a bandpass filter 23, a harmonic generation unit 24, and an addition unit 28.

The storage unit 21 is a non-volatile memory that stores the filter coefficient generated by the BPF coefficient generation unit 12. The storage unit 21 is not limited to the filter coefficient, and may store the above-mentioned physical characteristics such as the fundamental frequency FF and the lowest resonance frequency F0, the MAC address of the sound output device 3, and the like.

The bandpass filter 23 is a digital processing unit that extracts and outputs a signal having a fundamental frequency FF from the acoustic input signal s1 based on the filter coefficient read from the storage unit 21. The signal extracted by the bandpass filter 23 is output to the harmonic generation unit 24.

The harmonic generation unit 24 is a digital processing unit that generates harmonic overtone group components (harmonic components) of the signal output from the bandpass filter 23. The signal output from the bandpass filter 23 is a signal having a frequency 1/2 of the lowest resonance frequency F0, and the N harmonic overtone group component (N is an integer of 3 or more) generated by the harmonic generator 24 is the lowest. It has a frequency component higher than the resonance frequency F0. The harmonic signal sh having a harmonic overtone group component generated by the harmonic generation unit 24 is output to the addition unit 28.

The addition unit 28 is a digital processing unit that adds a harmonic signal sh to the acoustic input signal s1. By adding the harmonic signal sh to the acoustic input signal s1, the acoustic output signal s2 including the overtone group component is generated. The acoustic output signal s2 generated by the addition unit 28 is output to the sound output device 3.

In this pseudo bass processing device 2, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

[1-2. Fundamental frequency determination method and sound processing method]
Next, the fundamental frequency determination method and the acoustic processing method according to the present embodiment will be described.

FIG. 4 is a flowchart showing the fundamental frequency determination method and the acoustic processing method of the first embodiment.

The fundamental frequency determination method is a method of determining the fundamental frequency FF when performing pseudo-bass processing on the acoustic input signal s1.

As a fundamental frequency determination method, first, the acquisition unit 10 of the fundamental frequency determination device 1 acquires the lowest resonance frequency F0 of the sound output device 3 (step S11). The lowest resonance frequency F0 is input to the acquisition unit 10 by, for example, an engineer of the sound output device 3.

Next, the determination unit 11 determines the fundamental frequency FF based on the lowest resonance frequency F0 acquired by the acquisition unit 10 (step S12). The determination unit 11 in the present embodiment determines a frequency that is 1/2 of the lowest resonance frequency F0 as the fundamental frequency FF.

According to this fundamental frequency determination method, the fundamental frequency FF when performing pseudo-bass processing can be easily determined.

The sound processing method is a method of performing pseudo bass processing on the sound input signal s1.

Steps S11 and S12 of the acoustic processing method are the same as the fundamental frequency determination method described above.

In the present embodiment, after steps S11 and S12, the BPF coefficient generation unit 12 generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF determined by the determination unit 11. The filter coefficient generated by the BPF coefficient generation unit 12 is output to the pseudo bass processing device 2.

Next, the bandpass filter 23 of the pseudo bass processing device 2 is used to extract the signal of the fundamental frequency FF from the acoustic input signal s1 (step S13). Specifically, the bandpass filter 23 extracts the signal of the fundamental frequency FF from the acoustic input signal s1 by using the filter coefficient generated by the BPF coefficient generation unit 12. Then, the extracted fundamental frequency FF signal is output to the harmonic generation unit 24.

Next, a harmonic group component of the fundamental frequency FF is generated from the signal of the fundamental frequency FF (step S14). Specifically, the harmonic generation unit 24 generates a harmonic group component of the fundamental frequency FF based on the signal output from the bandpass filter 23, and outputs the harmonic group component to the addition unit 28.

Next, the harmonic signal sh including the overtone group component is added to the acoustic input signal s1 (step S15). As a result, the acoustic output signal s2 including the signal of the overtone group component is generated. The acoustic output signal s2 generated by the addition unit 28 is output to the sound output device 3 (step S16).

According to these steps S11 to S16, since the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output, the user can hear the sound including the fundamental frequency FF. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

The fundamental frequency determining method of the present embodiment may be realized by the hardware configuration of the fundamental frequency determining device 1 shown in FIG. FIG. 5 is a diagram showing an example of a hardware configuration of a computer 1000 that realizes the function of the fundamental frequency determining device 1 by software.

As shown in FIG. 5, the computer 1000 is a computer including an input device 1001, an output device 1002, a CPU 1003, an internal storage 1004, a RAM 1005, and a bus 1009. The input device 1001, the output device 1002, the CPU 1003, the built-in storage 1004, and the RAM 1005 are connected by the bus 1009.

The input device 1001 is a device that serves as a user interface such as an input button, a touch pad, and a touch panel display, and accepts operations by a user who is an engineer. The input device 1001 may be configured to accept a user's contact operation, a voice operation, a remote control, or the like.

The output device 1002 is a device that outputs a signal from the computer 1000, and may be a device that serves as a user interface such as a speaker or a display in addition to the signal output terminal.

The built-in storage 1004 is a flash memory or the like. Further, the built-in storage 1004 may store in advance a program for realizing the function of the fundamental frequency determining device 1 and / or an application using the functional configuration of the fundamental frequency determining device 1.

The RAM 1005 is a Random Access Memory, which is used to store data or the like when executing a program or application.

The CPU 1003 is a Central Processing Unit, which copies a program or application stored in the internal storage 1004 to the RAM 1005, and sequentially reads and executes instructions included in the program or application from the RAM 1005.

[1-3. Effect, etc.]
The fundamental frequency determining device 1 of the present embodiment is a fundamental frequency determining device that determines the fundamental frequency FF when performing pseudo bass processing on the acoustic input signal s1, and is a sound output device 3 that is the target of performing pseudo bass processing. It is provided with an acquisition unit 10 for acquiring the lowest resonance frequency F0 of the above, and a determination unit 11 for determining the fundamental frequency FF based on the lowest resonance frequency F0.

In this way, the determination unit 11 determines the fundamental frequency FF based on the lowest resonance frequency F0, which is the physical characteristic of the sound output device 3, so that the fundamental frequency FF can be easily determined.

Further, the determination unit 11 may determine a frequency that is 1/2 of the lowest resonance frequency as the fundamental frequency FF.

In this way, the determination unit 11 can easily determine the fundamental frequency FF by determining a frequency that is 1/2 of the lowest resonance frequency as the fundamental frequency FF.

The pseudo bass processing device 2 of the present embodiment is a pseudo bass processing device that performs pseudo bass processing on the acoustic input signal s1, and is a fundamental frequency FF determined by the fundamental frequency determining device 1 from the acoustic input signal s1. It includes a bandpass filter 23 that extracts and outputs a signal, and a harmonic generation unit 24 that generates harmonic group components of the signal output from the bandpass filter 23.

In this pseudo bass processing device 2, since the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output, the user can hear the sound including the fundamental frequency FF. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

The fundamental frequency determination method of the present embodiment is a method of determining the fundamental frequency FF when performing pseudo bass processing on the acoustic input signal s1, and is the lowest resonance frequency of the sound output device 3 which is the target of performing pseudo bass processing. It includes a step of acquiring F0 and a step of determining the fundamental frequency FF based on the lowest resonance frequency F0.

Since this fundamental frequency determination method includes a step of determining the fundamental frequency FF based on the lowest resonance frequency F0, which is a physical characteristic of the sound output device 3, the fundamental frequency FF can be easily determined.

The acoustic processing method of the present embodiment is an acoustic processing method that performs pseudo-bass processing on the acoustic input signal s1, and includes a step of acquiring the lowest resonance frequency F0 of the sound output device 3 that is the target of performing pseudo-bass processing. A step of determining the fundamental frequency FF in the pseudo-bass processing based on the lowest resonance frequency F0, a step of extracting the signal of the fundamental frequency FF from the acoustic input signal s1, and a step of extracting the signal of the fundamental frequency FF from the signal of the fundamental frequency FF, and the overtone group component of the fundamental frequency FF. The step of generating the signal of the above and the step of adding the signal of the harmonic group component to the acoustic input signal s1 are included.

Since this acoustic processing method has a step of adding the harmonic overtone group component of the fundamental frequency FF to the acoustic input signal s1, the user can hear the sound including the fundamental frequency FF. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

[1-4. Modification of Embodiment 1]
The configuration of the fundamental frequency determining device 1A and the pseudo bass processing device 2A in the modified example of the first embodiment will be described with reference to FIG. In this modification, an example will be described in which the filter coefficient of the bandpass filter 23 is not generated by the fundamental frequency determining device but is generated by the pseudo bass processing device 2A.

FIG. 6 is a block diagram showing the configurations of the fundamental frequency determining device 1A and the pseudo bass processing device 2A in the modified example of the first embodiment.

As shown in FIG. 6, the fundamental frequency determining device 1A includes an acquisition unit 10 that acquires the lowest resonance frequency F0 of the sound output device 3, and a determining unit 11 that determines the fundamental frequency FF.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 of the sound output device 3.

The determination unit 11 is a calculation unit that determines the fundamental frequency FF based on the lowest resonance frequency F0 acquired by the acquisition unit 10. The determination unit 11 of the modified example also determines a frequency that is 1/2 of the lowest resonance frequency F0 as the fundamental frequency. In the fundamental frequency determination device 1A, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11.

The fundamental frequency FF determined by the determination unit 11 is output to the pseudo bass processing device 2A. The fundamental frequency FF may be output to the pseudo bass processing device 2A via a recording medium such as a USB memory, or the pseudo bass is generated by directly connecting the fundamental frequency determining device 1A and the pseudo bass processing device 2A. It may be output to the processing device 2A.

As shown in FIG. 6, the pseudo bass processing device 2A includes a storage unit 21, a BPF coefficient generation unit 22 for generating a bandpass filter coefficient, a bandpass filter 23, a harmonic generation unit 24, and an addition unit 28. I have.

The storage unit 21 is a non-volatile memory that stores the fundamental frequency FF determined by the determination unit 11.

The BPF coefficient generation unit 22 is a calculation unit that generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF read from the storage unit 21. The filter coefficient generated by the BPF coefficient generation unit 22 is output to the bandpass filter 23.

The bandpass filter 23 is a digital processing unit that extracts and outputs a signal having a base frequency FF from the acoustic input signal s1 based on the filter coefficient output from the BPF coefficient generation unit 22. The signal extracted by the bandpass filter 23 is output to the harmonic generation unit 24.

The harmonic generation unit 24 is a digital processing unit that generates harmonic group components of the signal output from the bandpass filter 23. The harmonic signal sh having a harmonic overtone group component generated by the harmonic generation unit 24 is output to the addition unit 28.

The addition unit 28 is a digital processing unit that adds a harmonic signal sh to the acoustic input signal s1. By adding the harmonic signal sh to the acoustic input signal s1, the acoustic output signal s2 including the overtone group component is generated. The acoustic output signal s2 generated by the addition unit 28 is output to the sound output device 3.

Even in this pseudo bass processing device 2A, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

(Embodiment 2)
[2-1. Configuration of fundamental frequency determination device and pseudo bass processing device]
The configuration of the fundamental frequency determining device 1B and the pseudo bass processing device 2B according to the second embodiment will be described with reference to FIGS. 7 and 8. In the second embodiment, an example in which the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1 are used to generate the filter coefficient of the bandpass filter 23 will be described.

FIG. 7 is a block diagram showing the configurations of the fundamental frequency determining device 1B and the pseudo bass processing device 2B according to the second embodiment. FIG. 7 also shows a sound output device 3 connected to the pseudo bass processing device 2B.

As shown in FIG. 7, the basic sound frequency determining device 1B obtains the acquisition unit 10 for acquiring the lowest resonance frequency F0 and the attenuation characteristic c1 of the resonance frequency of the sound output device 3, and the amplification amount b1 in the low band of the acoustic input signal s1. A storage unit 15 for storing, a determination unit 11 for determining the base frequency FF, a BPF coefficient generation unit 12 for generating a bandpass filter coefficient, and an LBF (low boost filter) coefficient generation unit 16 for generating a low boost filter coefficient. It has.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 and the attenuation characteristic c1 of the sound output device 3.

FIG. 8 is a diagram showing the lowest resonance frequency F0 of the sound output device 3, the attenuation characteristic c1, and the fundamental frequency FF when performing pseudo-bass processing.

The attenuation characteristic c1 is a characteristic that shows an attenuation tendency (predetermined attenuation rate) in a frequency band lower than the lowest resonance frequency F0 of the sound output device 3. The attenuation characteristic c1 is a characteristic unique to the sound output device 3, and can take various values depending on the size and material of the sound output device 3. In the present embodiment, for example, the lowest resonance frequency F0 is 90 Hz, and the attenuation characteristic c1 is −24 dB / oct.

The lowest resonance frequency F0 and the attenuation characteristic c1 are input to the acquisition unit 10 by, for example, an engineer who develops the sound output device 3. The acquisition unit 10 receives the input of the graphically drawn resonance frequency characteristic (see the thick broken line in FIG. 8) and calculates the received resonance frequency characteristic to acquire the minimum resonance frequency F0 and the attenuation characteristic c1. You may.

The storage unit 15 is a memory for storing the amplification amount b1 in the low band of the acoustic input signal s1. The reason for amplifying the low-band signal of the acoustic input signal s1 is to amplify the frequency component in the vicinity of the lowest resonance frequency F0 so that the lowest resonance frequency F0 is apparently shifted to the low frequency range. By shifting the lowest resonance frequency F0 to a low frequency range, the fundamental frequency FF can be lowered to the lower band side, and the user can hear the sound including the lower fundamental frequency FF.

The amplification amount b1 is, for example, 6 dB, 3 dB, 9 dB, or the like, and in the present embodiment, the amplification amount b1 is 6 dB. In this example, the amplification amount b1 stored in the storage unit 15 is 6 dB, but it does not necessarily have to be that value. However, if the amplification amount b1 is set to an extremely large value (for example, 18 dB or the like), distortion occurs in the low frequency signal in the low boost filter 27 described later, so that the amplification amount b1 is preferably 9 dB or less.

The amplification amount b1 stored in the storage unit 15 is output to the determination unit 11 and the LBF coefficient generation unit 16.

The determination unit 11 is a calculation unit that obtains the fundamental frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1. From the attenuation characteristic c1, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in gain is the same as the value of the amount of amplification b1 with respect to the gain at the lowest resonance frequency F0. This frequency Fd is the lowest resonance frequency F0 shifted to an apparently low frequency.

FIG. 8 shows the frequency Fd at which the amount of decrease in gain is 6 dB with respect to the gain at the lowest resonance frequency F0. In the present embodiment, since the attenuation characteristic c1 is −24 dB / oct, the frequency Fd at which the amount of decrease is 6 dB is 1/4 octave lower than the lowest resonance frequency F0, and is 75.68 Hz.

The determination unit 11 determines a frequency that is 1/2 of the frequency Fd as the fundamental frequency FF. The fundamental frequency FF in the above example is 37.84 Hz. In the fundamental frequency determination device 1B, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11. Since the signal at the frequency Fd and the frequency near the frequency Fd is amplified by the low boost filter 27 described later, the frequency Fd is apparently the lowest resonance frequency shifted to the low frequency range.

The BPF coefficient generation unit 12 is a calculation unit that generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF determined by the determination unit 11. The LBF coefficient generation unit 16 is a calculation unit that generates the filter coefficient of the low boost filter 27 based on the amplification amount b1 stored in the storage unit 15. This filter coefficient can be calculated by a known method.

The filter coefficient generated by the BPF coefficient generation unit 12 and the filter coefficient generated by the LBF coefficient generation unit 16 are output to the pseudo bass processing device 2B. These filter coefficients may be output to the pseudo bass processing device 2B via a recording medium such as a USB memory, or may be simulated by directly connecting the fundamental frequency determining device 1B and the pseudo bass processing device 2B. It may be output to the bass processing device 2B.

As shown in FIG. 7, the pseudo bass processing device 2B includes a storage unit 21, a bandpass filter 23, a harmonic generation unit 24, a low boost filter 27, and an addition unit 28.

The storage unit 21 is a non-volatile memory that stores the filter coefficient generated by the BPF coefficient generation unit 12 and each filter coefficient generated by the LBF coefficient generation unit 16. The filter coefficient generated by the BPF coefficient generation unit 12 is read by the bandpass filter 23, and the filter coefficient generated by the LBF coefficient generation unit 16 is read by the low boost filter 27.

The bandpass filter 23 is a digital processing unit that extracts and outputs a signal having a base frequency FF from the acoustic input signal s1 based on the filter coefficient generated by the BPF coefficient generation unit 12. The signal extracted by the bandpass filter 23 is output to the harmonic generation unit 24.

The harmonic generation unit 24 is a digital processing unit that generates harmonic group components of the signal output from the bandpass filter 23. The harmonic signal sh having the overtone group component generated by the harmonic generation unit 24 is output to the low boost filter 27.

The low boost filter 27 amplifies the harmonic signal sh based on the filter coefficient generated by the LBF coefficient generation unit 16. At that time, the low boost filter 27 amplifies the harmonic signal sh with at least an amplification amount b1. The boost signal sb amplified by the low boost filter 27 is output to the addition unit 28.

The reason why the harmonic signal sh is amplified by the low boost filter 27 is as follows. Since the signal output from the bandpass filter 23 is a signal having a frequency of 1/2 of the frequency Fd, the harmonic overtone group component apparently has a frequency equal to or higher than the lowest resonance frequency shifted to the low frequency range. Therefore, a frequency component lower than the lowest resonance frequency F0 is also included. Therefore, by amplifying the harmonic signal sh with the low boost filter 27, the output deterioration of the frequency component lower than the lowest resonance frequency F0 is suppressed.

The addition unit 28 is a digital processing unit that adds a boost signal sb to the acoustic input signal s1. By adding the boost signal sb to the acoustic input signal s1, the acoustic output signal s2 including the overtone group component and amplified is generated. The acoustic output signal s2 generated by the addition unit 28 is output to the sound output device 3.

Even in this pseudo bass processing device 2B, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

Further, the fundamental frequency determining device 1B further includes a storage unit 15 for storing the amplification amount b1 in the low band of the acoustic input signal s1. The acquisition unit 10 further acquires the attenuation characteristic c1 in the frequency band lower than the minimum resonance frequency F0 of the sound output device 3, and the determination unit 11 further acquires the attenuation characteristic c1 in the frequency band lower than the minimum resonance frequency F0 of the sound output device 3, and the determination unit 11 is based on the minimum resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1. The fundamental frequency FF may be determined.

In this way, the determination unit 11 simply determines the fundamental frequency FF by determining the fundamental frequency FF based on the minimum resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1, which are the physical characteristics of the sound output device 3. be able to.

Further, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in the gain is the same as the value of the amplification amount b1 with respect to the gain at the lowest resonance frequency F0 from the attenuation characteristic c1, and obtains 1 / of the frequency Fd. The frequency of 2 may be determined as the fundamental frequency FF.

According to this, since the apparent lowest resonance frequency can be shifted to a low band, the fundamental frequency FF can be lowered to a lower band side. This makes it possible for the user to hear a sound including a lower fundamental frequency FF, and can improve the sound quality of the sound output from the sound output device 3.

Further, the pseudo-bass processing device 2B of the present embodiment is a pseudo-bass processing device that performs pseudo-bass processing on the acoustic input signal s1, and the basal frequency determined by the basal frequency determining device 1B from the acoustic input signal s1. The bandpass filter 23 that extracts and outputs the FF signal, the harmonic generation unit 24 that generates the overtone group component of the signal output from the bandpass filter 23, and the signal generated by the harmonic generation unit 24 are amplified at least by the amount b1. It is provided with a low boost filter 27 which is amplified by.

In this pseudo bass processing device 2B, since the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output, the user can hear the sound including the fundamental frequency FF. Further, by amplifying the harmonic signal sh with the low boost filter 27, it is possible to suppress the output deterioration of the frequency component lower than the lowest resonance frequency F0. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

[2-2. Modification of Embodiment 2]
The configuration of the fundamental frequency determining device 1C and the pseudo bass processing device 2C in the modified example of the second embodiment will be described with reference to FIG. In this modification, an example will be described in which the filter coefficient of the bandpass filter 23 and the filter coefficient of the low boost filter 27 are not generated by the fundamental frequency determining device but are generated by the pseudo bass processing device 2C.

FIG. 9 is a block diagram showing the configurations of the fundamental frequency determining device 1C and the pseudo bass processing device 2C in the modified example of the second embodiment.

As shown in FIG. 9, the fundamental frequency determining device 1C stores the acquisition unit 10 that acquires the lowest resonance frequency F0 and the attenuation characteristic c1 of the sound output device 3 and the amplification amount b1 in the low band of the acoustic input signal s1. A unit 15 and a determination unit 11 for determining the fundamental frequency FF are provided.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 and the attenuation characteristic c1 of the sound output device 3.

The storage unit 15 is a memory for storing the amplification amount b1 in the low band of the acoustic input signal s1. The amplification amount b1 stored in the storage unit 15 is output to the determination unit 11 and the storage unit 21.

The determination unit 11 is a calculation unit that obtains the fundamental frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1. From the attenuation characteristic c1, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in gain is the same as the value of the amount of amplification b1 with respect to the gain at the lowest resonance frequency F0.

The determination unit 11 determines a frequency that is 1/2 of the frequency Fd as the fundamental frequency FF. In the fundamental frequency determining device 1C, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11.

The fundamental frequency FF determined by the determination unit 11 and the amplification amount b1 stored in the storage unit 15 are output to the pseudo bass processing device 2C. The fundamental frequency FF may be output to the pseudo bass processing device 2C via a recording medium such as a USB memory, or the pseudo bass is generated by directly connecting the fundamental frequency determining device 1C and the pseudo bass processing device 2C. It may be output to the processing device 2C.

As shown in FIG. 9, the pseudo bass processing device 2C has a storage unit 21, a BPF coefficient generation unit 22 that generates a bandpass filter coefficient, a bandpass filter 23, a harmonic generation unit 24, and a low boost filter coefficient. It includes an LBF coefficient generating unit 26 to be generated, a low boost filter 27, and an adding unit 28.

The storage unit 21 is a non-volatile memory that stores the fundamental frequency FF determined by the determination unit 11 and the amplification amount b1 output from the storage unit 15.

The BPF coefficient generation unit 22 is a calculation unit that generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF stored in the storage unit 21. The filter coefficient generated by the BPF coefficient generation unit 22 is output to the bandpass filter 23.

The LBF coefficient generation unit 26 is a calculation unit that generates the filter coefficient of the low boost filter 27 based on the amplification amount b1 stored in the storage unit 21. The filter coefficient generated by the LBF coefficient generation unit 26 is output to the low boost filter 27.

The bandpass filter 23 is a digital processing unit that extracts and outputs a signal having a base frequency FF from the acoustic input signal s1 based on the filter coefficient output from the BPF coefficient generation unit 22. The signal extracted by the bandpass filter 23 is output to the harmonic generation unit 24.

The harmonic generation unit 24 is a digital processing unit that generates harmonic group components of the signal output from the bandpass filter 23. The harmonic signal sh having the overtone group component generated by the harmonic generation unit 24 is output to the low boost filter 27.

The low boost filter 27 amplifies the harmonic signal sh based on the filter coefficient generated by the LBF coefficient generation unit 26. The boost signal sb amplified by the low boost filter 27 is output to the addition unit 28.

The addition unit 28 is a digital processing unit that adds a boost signal sb to the acoustic input signal s1. By adding the boost signal sb to the acoustic input signal s1, the acoustic output signal s2 including the overtone group component and amplified is generated. The acoustic output signal s2 generated by the addition unit 28 is output to the sound output device 3.

Even in this pseudo bass processing device 2C, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

(Embodiment 3)
[3-1. Configuration of fundamental frequency determination device and pseudo bass processing device]
The configuration of the fundamental frequency determining device 1D and the pseudo bass processing device 2D according to the third embodiment will be described with reference to FIG. In the third embodiment, an example in which the amplification amount b1 is not stored in the storage unit but is acquired by the acquisition unit 10 will be described.

FIG. 10 is a block diagram showing the configurations of the fundamental frequency determining device 1D and the pseudo bass processing device 2D according to the third embodiment. FIG. 10 also shows a sound output device 3 connected to the pseudo bass processing device 2D.

As shown in FIG. 10, the basic sound frequency determination device 1D includes an acquisition unit 10 that acquires the lowest resonance frequency F0, an attenuation characteristic c1 and an amplification amount b1 of the sound output device 3, a determination unit 11 that determines the basic sound frequency FF, and the determination unit 11. It includes a BPF coefficient generation unit 12 that generates a bandpass filter coefficient, and an LBF coefficient generation unit 16 that generates a low boost filter coefficient.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 of the sound output device 3, the attenuation characteristic c1, and the amplification amount b1 in the low band of the acoustic input signal s1.

The determination unit 11 is a calculation unit that obtains the fundamental frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1. From the attenuation characteristic c1, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in gain is the same as the value of the amount of amplification b1 with respect to the gain at the lowest resonance frequency F0.

The determination unit 11 determines a frequency that is 1/2 of the frequency Fd as the fundamental frequency FF. In the fundamental frequency determination device 1D, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11.

The BPF coefficient generation unit 12 is a calculation unit that generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF determined by the determination unit 11. The LBF coefficient generation unit 16 is a calculation unit that generates the filter coefficient of the low boost filter 27 based on the amplification amount b1 acquired by the acquisition unit 10. The filter coefficient generated by the BPF coefficient generation unit 12 and the filter coefficient generated by the LBF coefficient generation unit 16 are output to the pseudo bass processing device 2D.

As shown in FIG. 10, the pseudo bass processing device 2D includes a storage unit 21, a bandpass filter 23, a harmonic generation unit 24, a low boost filter 27, and an addition unit 28. Since these components are the same as those in the second embodiment, description thereof will be omitted.

Even in this pseudo bass processing device 2D, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

Further, the acquisition unit 10 further acquires the attenuation characteristic c1 in the frequency band lower than the lowest resonance frequency F0 of the sound output device 3, and the amplification amount b1 in the low band of the acoustic input signal s1, and the determination unit 11 determines. The base frequency FF may be determined based on the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1.

In this way, the determination unit 11 simply determines the fundamental frequency FF by determining the fundamental frequency FF based on the minimum resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1, which are the physical characteristics of the sound output device 3. be able to.

Further, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in the gain is the same as the value of the amplification amount b1 with respect to the gain at the lowest resonance frequency F0 from the attenuation characteristic c1, and obtains 1 / of the frequency Fd. The frequency of 2 may be determined as the fundamental frequency FF.

According to this, since the apparent lowest resonance frequency can be shifted to a low band, the fundamental frequency FF can be lowered to a lower band side. This makes it possible for the user to hear a sound including a lower fundamental frequency FF, and can improve the sound quality of the sound output from the sound output device 3.

[3-2. Modification of Embodiment 3]
The configuration of the fundamental frequency determining device 1E and the pseudo bass processing device 2E in the modified example of the third embodiment will be described with reference to FIG. In this modification, an example will be described in which the filter coefficient of the bandpass filter 23 and the filter coefficient of the low boost filter 27 are not generated by the fundamental frequency determining device but are generated by the pseudo bass processing device 2E.

FIG. 11 is a block diagram showing the configurations of the fundamental frequency determining device 1E and the pseudo bass processing device 2E in the modified example of the third embodiment.

As shown in FIG. 11, the fundamental frequency determining device 1E includes an acquisition unit 10 for acquiring the lowest resonance frequency F0, an attenuation characteristic c1 and an amplification amount b1 of the sound output device 3, and a determining unit 11 for determining the fundamental frequency FF. I have.

The acquisition unit 10 is a reception input unit that acquires the lowest resonance frequency F0 of the sound output device 3, the attenuation characteristic c1, and the amplification amount b1 in the low band of the acoustic input signal s1. The lowest resonance frequency F0 and the attenuation characteristic c1 acquired by the acquisition unit 10 are output to the determination unit 11, and the amplification amount b1 is output to the determination unit 11 and the pseudo bass processing device 2E.

The determination unit 11 is a calculation unit that obtains the fundamental frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1 and the amplification amount b1. From the attenuation characteristic c1, the determination unit 11 obtains the frequency Fd at which the value of the amount of decrease in gain is the same as the value of the amount of amplification b1 with respect to the gain at the lowest resonance frequency F0.

The determination unit 11 determines a frequency that is 1/2 of the frequency Fd as the fundamental frequency FF. In the fundamental frequency determining device 1E, the fundamental frequency FF can be easily determined by the calculation of the determination unit 11.

The fundamental frequency FF determined by the determination unit 11 and the amplification amount b1 acquired by the acquisition unit 10 are output to the pseudo bass processing device 2E.

As shown in FIG. 11, the pseudo bass processing device 2E has a storage unit 21, a BPF coefficient generation unit 22 that generates a bandpass filter coefficient, a bandpass filter 23, a harmonic generation unit 24, and a low boost filter coefficient. It includes an LBF coefficient generating unit 26 to be generated, a low boost filter 27, and an adding unit 28.

The storage unit 21 stores the fundamental frequency FF output from the determination unit 11 and the amplification amount b1 output from the acquisition unit 10.

The BPF coefficient generation unit 22 generates the filter coefficient of the bandpass filter 23 based on the fundamental frequency FF stored in the storage unit 21. The LBF coefficient generation unit 26 generates the filter coefficient of the low boost filter 27 based on the amplification amount b1 stored in the storage unit 21. Since the following components are the same as those of the modified example of the second embodiment, the description thereof will be omitted.

Even in this pseudo bass processing device 2E, the harmonic group component of the fundamental frequency FF is added to the acoustic input signal s1 and output. Therefore, even if the sound output device 3 cannot reproduce the frequency component that is the fundamental tone, the user The sound including the fundamental frequency FF can be heard. Thereby, the sound quality of the sound output from the sound output device 3 can be improved.

(Other embodiments)
The fundamental frequency determining device and the like of the present disclosure have been described above based on the embodiment and the like, but the present disclosure is not limited to this embodiment. For example, another embodiment realized by arbitrarily combining the components described in the present specification and excluding some of the components may be the embodiment of the present disclosure. The present disclosure also includes modifications obtained by making various modifications that can be conceived by those skilled in the art within the scope of the gist of the present disclosure, that is, the meaning indicated by the wording described in the claims, with respect to the above embodiment. Is done.

The forms shown below may also be included within the scope of one or more aspects of the present disclosure.

(1) A part of the components constituting the basic tone frequency determining device and the like may be a computer system composed of a microprocessor, a ROM, a RAM, a hard disk unit, a display unit, a keyboard, a mouse and the like. A computer program is stored in the RAM or the hard disk unit. The microprocessor achieves its function by operating according to the computer program. Here, a computer program is configured by combining a plurality of instruction codes indicating commands to a computer in order to achieve a predetermined function.

(2) A part of the components constituting the fundamental frequency determining device and the like may be composed of one system LSI (Large Scale Integration: large-scale integrated circuit). A system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip, and specifically, is a computer system including a microprocessor, a ROM, a RAM, and the like. .. A computer program is stored in the RAM. When the microprocessor operates according to the computer program, the system LSI achieves its function.

(3) Some of the components constituting the fundamental frequency determining device and the like may be composed of an IC card or a single module that can be attached to and detached from each device. The IC card or the module is a computer system composed of a microprocessor, a ROM, a RAM, and the like. The IC card or the module may include the above-mentioned super multifunctional LSI. When the microprocessor operates according to a computer program, the IC card or the module achieves its function. This IC card or this module may have tamper resistance.

(4) Further, some of the components constituting the basic tone frequency determining device and the like are a computer program or a recording medium capable of reading the digital signal by a computer, for example, a flexible disk, a hard disk, a CD-ROM, or an MO. , DVD, DVD-ROM, DVD-RAM, BD (Blu-ray (registered trademark) Disc), semiconductor memory, or the like. Further, it may be the digital signal recorded on these recording media.

In addition, some of the components constituting the basic tone frequency determining device and the like transmit the computer program or the digital signal via a telecommunication line, a wireless or wired communication line, a network typified by the Internet, data broadcasting, and the like. And may be transmitted.

(5) The present disclosure may be the method shown above. Further, it may be a computer program that realizes these methods by a computer, or it may be a digital signal composed of the computer program.

(6) Further, the present disclosure is a computer system including a microprocessor and a memory, in which the memory stores the computer program, and the microprocessor may operate according to the computer program. ..

(7) Further, another independent computer by recording and transferring the program or the digital signal on the recording medium, or by transferring the program or the digital signal via the network or the like. It may be implemented by the system.

(8) The above-described embodiment and the above-described modification may be combined.

The fundamental frequency determining device of the present disclosure is applied to determine the fundamental frequency when performing pseudo-bass processing in devices such as televisions, car audios, smartphones, tablets, portable speakers, headphones, earphones, and sound bars.

1, 1A, 1B, 1C, 1D, 1E Basic frequency determination device 2, 2A, 2B, 2C, 2D, 2E Pseudo bass processing device 3 Sound output device 5 Sound processing system 10 Acquisition unit 11 Determination unit 12 BPF coefficient generation unit 15 Storage unit 16 LBF coefficient generation unit 21 Storage unit 22 BPF coefficient generation unit 23 Bandpass filter 24 Harmonic generation unit 26 LBF coefficient generation unit 27 Low boost filter 28 Addition unit 1000 Computer 1001 Input device 1002 Output device 1003 CPU
1004 Internal storage 1005 RAM
1009 Bus b1 Amplification amount c1 Attenuation characteristic F0 Minimum resonance frequency Fd frequency (apparently the lowest resonance frequency shifted to the low frequency range)
FF Fundamental frequency s1 Acoustic input signal s2 Acoustic output signal sb Boost signal sh Harmonic signal

Claims (10)

It is a fundamental frequency determination device that determines the fundamental frequency when performing pseudo-bass processing on an acoustic input signal.
An acquisition unit that acquires the lowest resonance frequency of the sound output device that is the target of the pseudo-bass processing, and
A fundamental frequency determining device including a determination unit for determining the fundamental frequency based on the lowest resonance frequency. The fundamental frequency determining device according to claim 1, wherein the determination unit determines a frequency halved of the lowest resonance frequency as the fundamental frequency. Further, a storage unit for storing the amplification amount in the low band of the acoustic input signal is provided.
The acquisition unit further acquires the attenuation characteristic in the frequency band lower than the minimum resonance frequency of the sound output device.
The fundamental frequency determination device according to claim 1, wherein the determination unit determines the fundamental frequency based on the minimum resonance frequency, the attenuation characteristic, and the amplification amount. From the attenuation characteristic, the determination unit obtains a frequency at which the value of the amount of decrease in the gain is the same as the value of the amount of amplification with respect to the gain at the lowest resonance frequency, and the frequency is halved of the frequency. The fundamental frequency determining device according to claim 3, wherein the fundamental frequency is determined as the fundamental frequency. The acquisition unit further acquires the attenuation characteristic in the frequency band lower than the minimum resonance frequency of the sound output device and the amplification amount in the low band of the acoustic input signal.
The fundamental frequency determination device according to claim 1, wherein the determination unit determines the fundamental frequency based on the minimum resonance frequency, the attenuation characteristic, and the amplification amount. From the attenuation characteristic, the determination unit obtains a frequency at which the value of the amount of decrease in the gain is the same as the value of the amount of amplification with respect to the gain at the lowest resonance frequency, and the frequency is halved of the frequency. The fundamental frequency determining device according to claim 5, wherein the fundamental frequency is determined as the fundamental frequency. A pseudo-bass processing device that performs pseudo-bass processing on an acoustic input signal.
A bandpass filter that extracts and outputs a signal of the fundamental frequency determined by the fundamental frequency determining device according to any one of claims 1 to 6 from the acoustic input signal.
A pseudo-bass processing device including a harmonic generator that generates overtone group components of the signal output from the bandpass filter. A pseudo-bass processing device that performs pseudo-bass processing on an acoustic input signal.
A bandpass filter that extracts and outputs a signal of the fundamental frequency determined by the fundamental frequency determining device according to any one of claims 3 to 6 from the acoustic input signal.
A harmonic generator that generates overtone group components of the signal output from the bandpass filter, and
A pseudo bass processing device including a low boost filter that amplifies the signal generated by the harmonic generation unit by at least the amplification amount. It is a method of determining the fundamental frequency when performing pseudo bass processing on an acoustic input signal.
The step of acquiring the lowest resonance frequency of the sound output device to be subjected to the pseudo bass processing, and
A method for determining a fundamental frequency, which comprises a step of determining the fundamental frequency based on the lowest resonance frequency. It is an acoustic processing method that performs pseudo bass processing on an acoustic input signal.
The step of acquiring the lowest resonance frequency of the sound output device to be subjected to the pseudo bass processing, and
The step of determining the fundamental frequency in the pseudo-bass processing based on the lowest resonance frequency, and
The step of extracting the signal of the fundamental frequency from the acoustic input signal and
A step of generating a signal of a harmonic overtone group component of the fundamental frequency from the signal of the fundamental frequency, and
An acoustic processing method including a step of adding a signal of a harmonic overtone group component to the acoustic input signal.

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