CN111968672B - Pitch frequency determining device and method, analog bass processing device, and sound processing method - Google Patents
Pitch frequency determining device and method, analog bass processing device, and sound processing method Download PDFInfo
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- CN111968672B CN111968672B CN202010798585.1A CN202010798585A CN111968672B CN 111968672 B CN111968672 B CN 111968672B CN 202010798585 A CN202010798585 A CN 202010798585A CN 111968672 B CN111968672 B CN 111968672B
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Classifications
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
- G10L25/27—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the analysis technique
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
- G10L25/48—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 specially adapted for particular use
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
- G10L25/75—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 for modelling vocal tract parameters
Abstract
Provided are a pitch frequency determination device and method, a simulated bass processing device, and a sound processing method, which can simply determine a pitch frequency when performing simulated bass processing. The pitch frequency determination device (1) is a pitch frequency determination device for determining a pitch frequency FF when performing analog bass processing on an acoustic input signal s1, and is provided with: an obtaining unit (10) that obtains the lowest resonance frequency (F0) of the audio output device (3) to which the signal subjected to the analog bass process is input; and a determination unit (11) that determines a pitch frequency FF from the lowest resonance frequency F0.
Description
Technical Field
The present disclosure relates to a pitch frequency determination device, a pitch frequency determination method, a simulated bass processing device, and a sound processing method that determine a pitch frequency (Fundamental Frequency: fundamental frequency) when performing simulated bass processing on a sound input signal.
Background
In order to enhance the bass component of sound output from a speaker, a frequency equalizer is widely used. The user can intuitively set which frequency band in the bass component is amplified to which degree by operating the frequency equalizer. However, frequency components that cannot be reproduced by the speaker cannot be enhanced in the frequency equalizer, that is, frequency components lower than the lowest resonance frequency of the speaker cannot be enhanced.
As a technique for enhancing a frequency component which cannot be reproduced by a speaker, there is known a technique for processing an analog bass using a psychoacoustic phenomenon, i.e., a vanishing fundamental frequency (missing fundamental) (for example, refer to patent document 1). The phenomenon of the missing fundamental frequency is a phenomenon that even if the fundamental tone is missing, the missing fundamental tone can be perceived even if the overtone component thereof (for example, in the case of 50Hz fundamental tone, the overtone component is 100Hz, 150Hz, 200Hz …) is present. In the acoustic processing system using such an analog bass processing technique, since the overtone component of the pitch frequency is added to the acoustic input signal and output, even if the speaker cannot reproduce the frequency component to be the pitch, the user can feel that the sound including the pitch frequency is heard.
(prior art literature)
(patent literature)
Patent document 1 japanese patent No. 4286510
However, when a technician who develops a speaker does not know the analog bass processing technique, it may be difficult to determine the pitch frequency at the time of performing the analog bass processing.
Disclosure of Invention
In view of the above-described problems, an object of the present disclosure is to provide a pitch frequency determination device and the like that can easily determine a pitch frequency when an analog bass process is performed on an acoustic input signal.
The present disclosure provides a pitch frequency determination device for determining a pitch frequency when performing an analog bass process on an acoustic input signal, the pitch frequency determination device comprising: an obtaining unit that obtains a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; and a determining unit configured to determine the pitch frequency based on the lowest resonance frequency.
An analog bass processing apparatus according to the present disclosure performs analog bass processing on an acoustic input signal, and includes: a band-pass filter for extracting the signal of the pitch frequency determined by the pitch frequency determining device from the acoustic input signal and outputting the signal; and a harmonic generation unit that generates an overtone component of the signal output from the band-pass filter.
An analog bass processing apparatus according to the present disclosure performs analog bass processing on an acoustic input signal, and includes: a band-pass filter for extracting the signal of the pitch frequency determined by the pitch frequency determining device from the acoustic input signal and outputting the signal; a harmonic generation unit that generates an overtone component of the signal output from the band-pass filter; and a low-frequency-domain amplification filter that amplifies the signal generated by the harmonic generation unit by at least an amplification amount.
A pitch frequency determination method in the present disclosure determines a pitch frequency when performing an analog bass process on an acoustic input signal, the pitch frequency determination method including the steps of: a step of obtaining a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; and determining the pitch frequency based on the lowest resonance frequency.
The sound processing method in the present disclosure performs simulated bass processing on a sound input signal, and includes the steps of: a step of obtaining a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; determining a pitch frequency in the analog bass process based on the lowest resonance frequency; extracting the signal of the fundamental tone frequency from the acoustic input signal; generating a signal of an overtone component of the fundamental tone frequency from the signal of the fundamental tone frequency; and adding the signal of the overtone component to the acoustic input signal.
The general and specific aspects may be realized by a system, a method, an integrated circuit, a computer program, a computer-readable recording medium such as a CD-ROM, or any combination of the system, the method, the integrated circuit, the computer program, and the recording medium.
The pitch frequency determination device and the like of the present disclosure can simply determine the pitch frequency when analog bass processing is performed on an acoustic input signal.
Drawings
Fig. 1 shows an example of an analog bass processing apparatus.
Fig. 2 is a block diagram showing the configuration of the pitch frequency determining apparatus and the analog bass processing apparatus according to embodiment 1.
Fig. 3 shows the lowest resonance frequency of the audio output device to which the analog bass process is applied, and the pitch frequency at the time of the analog bass process.
Fig. 4 is a flowchart showing a pitch frequency determination method and an acoustic processing method according to embodiment 1. Fig. 5 shows an example of a hardware configuration of a computer in which the functions of the pitch frequency deciding apparatus according to embodiment 1 are realized by software.
Fig. 6 is a block diagram showing the configuration of a pitch frequency determining device and an analog bass processing device in a modification of embodiment 1.
Fig. 7 is a block diagram showing the configuration of the pitch frequency determining apparatus and the analog bass processing apparatus according to embodiment 2.
Fig. 8 shows the lowest resonance frequency, attenuation characteristics, and pitch frequency of the audio output apparatus when analog bass processing is performed.
Fig. 9 is a block diagram showing the configuration of a pitch frequency deciding apparatus and an analog bass processing apparatus according to a modification of embodiment 2.
Fig. 10 is a block diagram showing the configuration of a pitch frequency determining apparatus and an analog bass processing apparatus in embodiment 3.
Fig. 11 is a block diagram showing the configuration of a pitch frequency determination device and an analog bass processing device in a modification of embodiment 3.
Symbol description
1. 1A, 1B, 1C, 1D, 1E pitch frequency determining device
2. 2A, 2B, 2C, 2D, 2E analog bass processing device
3. Sound output device
5. Sound processing system
10. Acquisition unit
11. Determination unit
12 BPF coefficient generation unit
15. Storage part
16 LBF coefficient generating part
21. Storage unit
22 BPF coefficient generation unit
23. Band-pass filter
24. Harmonic generation unit
26 LBF coefficient generating part
27. Low frequency domain amplifying filter
28. Addition unit
1000. Computer with a memory for storing data
1001. Input device
1002. Output device
1003 CPU
1004. Built-in memory device
1005 RAM
1009. Bus line
b1 Amplification amount
c1 Attenuation characteristics
F0 Lowest resonant frequency
Fd frequency (minimum resonance frequency seen to be shifted to low frequency domain)
FF pitch frequency
s1 acoustic input signal
s2 sound output signal
sb amplified signal
sh harmonic signal
Detailed Description
(implementing the warp and weft of the present disclosure)
There are many audio output devices such as speakers and headphones, and in the future, it is expected that the manufacturers developing the audio output devices will make more adjustments to the sound quality of the audio output devices. As one of the cases of performing sound quality adjustment of the sound output apparatus, the following analog bass processing apparatus 102 may be used when the above-described analog bass processing is introduced.
Fig. 1 shows an example of an analog bass processing apparatus 102. Fig. 1 also shows a sound output device 3 such as a speaker connected to the analog bass processing device 102.
The analog bass processing apparatus 102 shown in fig. 1 includes: a band-pass filter 23 for extracting a pitch frequency from the acoustic input signal s 1; a harmonic generation unit 24 that generates an overtone component of the signal output from the band-pass filter 23; and an adder 28 for adding the harmonic signal sh generated by the harmonic generator 24 to the acoustic input signal s 1. In the analog bass processing apparatus 102, since the overtone component of the fundamental tone frequency is added to the acoustic input signal s1 and output, the user can feel that the user hears the sound including the fundamental tone frequency.
In order to realize such analog bass processing, the above-described pitch frequency needs to be set in advance and input to the band-pass filter 23. However, when a technician who develops the audio output apparatus 3 does not know the analog bass processing technique, it is difficult to determine the pitch frequency at the time of performing the analog bass processing. It is also possible to consider that a technician of the sound output apparatus 3 has sufficiently grasped the physical characteristics of the sound output apparatus 3, such as the resonance frequency characteristics and the like.
Accordingly, the present disclosure provides a pitch frequency determination device and the like capable of simply determining a pitch frequency by utilizing physical characteristics and the like of the audio output device 3.
The embodiments are specifically described below with reference to the drawings. In addition, the embodiments to be described below are one specific example of the present disclosure. The numerical values, shapes, materials, components, arrangement positions of components, connection modes, steps, orders of steps, and the like shown in the following embodiments are examples, and the gist of the present disclosure is not limited thereto. Among the constituent elements of the following embodiments, constituent elements of the independent claims of the embodiment according to one aspect of the present disclosure are not described, and are described as arbitrary constituent elements. The embodiments of the present disclosure are not limited by the present independent technical solutions, but may be expressed by other independent technical solutions.
The respective figures are schematic views, and are not strict views. In the drawings, substantially the same components are denoted by the same reference numerals, and overlapping description may be omitted or simplified.
(embodiment 1)
[1-1. Pitch frequency determination device and Structure of analog Bass processing device ]
The configuration of the pitch frequency determining apparatus and the analog bass processing apparatus according to embodiment 1 will be described with reference to fig. 2 and 3.
Fig. 2 is a block diagram showing the structures of the pitch frequency determining apparatus 1 and the analog bass processing apparatus 2 in embodiment 1. Fig. 2 also shows a sound output device 3 connected to the analog bass processing device 2. Fig. 2 also shows an acoustic processing system 5 including a pitch frequency determining apparatus 1, an analog bass processing apparatus 2, and an audio output apparatus 3.
The audio output device 3 converts the audio output signal s2 output from the analog bass processing device 2 into audio and outputs the audio, and is, for example, a speaker or an earphone. In the present embodiment, the audio output device 3 is a device to which a signal subjected to the analog bass process is input, and is configured to output, for example, audio in a frequency band of 90Hz or more, and gradually attenuate audio in a frequency band lower than 90 Hz. Therefore, sound quality adjustment by the analog bass process is performed based on the sound output device 3.
The pitch frequency determining apparatus 1 and the analog bass processing apparatus 2 will be described in order.
The pitch frequency determining apparatus 1 is an apparatus for determining a pitch frequency FF, and is, for example, a personal computer having a program for determining a pitch frequency FF installed therein.
As shown in fig. 2, the pitch frequency determination device 1 includes: an obtaining section 10 that obtains a lowest resonance frequency F0 of the sound output device 3; a determination unit 11 that determines a pitch frequency FF; and a BPF (band-pass filter) coefficient generation unit 12 that generates a band-pass filter coefficient.
The obtaining section 10 obtains the lowest resonance frequency F0 of the sound output device 3. The lowest resonance frequency F0 is input to the obtaining unit 10 by, for example, a technician of the sound output device 3 who has grasped the physical characteristics of the sound output device 3.
Fig. 3 shows the lowest resonance frequency F0 of the audio output apparatus 3 to which the signal subjected to the analog bass process is input, and the pitch frequency FF at the time of the analog bass process. The solid line in fig. 3 is an actual measurement value of the resonance frequency characteristic of the audio output device 3, and the thick dotted line indicates a straight line approximation of the resonance frequency characteristic.
The lowest resonance frequency F0 is a frequency at which the output of the signal starts to decay in the low frequency domain in terms of the frequency characteristics of the sound output device 3. The lowest resonance frequency F0 is a characteristic value of the sound output device 3, and can be set to various values according to the size, material, and the like of the sound output device 3. The lowest resonance frequency F0 of the sound output device 3 in the present embodiment is 90Hz. The resonance frequency characteristic is attenuated at a certain inclination in a frequency band lower than the lowest resonance frequency F0.
The determining unit 11 has an arithmetic function of determining the pitch frequency FF based on the lowest resonance frequency F0 obtained by the obtaining unit 10. The determination unit 11 of the present embodiment determines the frequency 1/2 of the lowest resonance frequency F0 as the pitch frequency. In the pitch frequency determination device 1, the pitch frequency FF can be determined simply by the calculation of the determination unit 11.
In fig. 3, the lowest resonance frequency F0 is 90Hz, and the pitch frequency FF is 45Hz. In the above description, the value of 1/2 of the lowest resonance frequency F0 is determined as the pitch frequency FF, but the value is not strict. For example, as long as the audio output apparatus 3 can reproduce a frequency component 2 times the pitch frequency FF, the pitch frequency FF is not limited to 1/2 of the lowest resonance frequency F0, and may be a value of 3/8 or more and 5/8 or less.
The BPF coefficient generation unit 12 has an arithmetic function of generating a filter coefficient of the bandpass filter 23 described later based on the pitch frequency FF determined by the determination unit 11. The filter coefficients can be calculated by a known method. The filter coefficient is generated so that the pitch frequency FF becomes the center frequency of the band-pass filter 23. However, the filter coefficient is not necessarily generated so that the pitch frequency FF becomes the center frequency of the band pass filter 23, and may be generated so that the pitch frequency FF is included in the half width of the band pass filter 23.
The filter coefficients generated by the BPF coefficient generating unit 12 are output to the analog bass processing apparatus 2. The filter coefficients may be output to the analog bass processing apparatus 2 via a recording medium such as a USB memory, for example, or may be output to the analog bass processing apparatus 2 by directly connecting the pitch frequency determining apparatus 1 to the analog bass processing apparatus 2.
The analog bass processing apparatus 2 is, for example, an apparatus built in a speaker or an earphone. The analog bass processing device 2 performs analog bass processing on the acoustic input signal s1, and outputs the processed signal to the sound output device 3. The acoustic input signal s1 is input to the analog bass processing apparatus 2, and then branched, one acoustic input signal s1 after branching is output to the adder 28, and the other acoustic input signal s1 is output to the band-pass filter 23.
As shown in fig. 2, the analog bass processing apparatus 2 includes: a storage unit 21, a band-pass filter 23, a harmonic generation unit 24, and an addition unit 28.
The storage unit 21 is a nonvolatile memory that stores the filter coefficients generated by the BPF coefficient generation unit 12. The storage unit 21 may store physical characteristics such as the pitch frequency FF and the lowest resonance frequency F0, and the MAC address of the audio output apparatus 3, instead of just the filter coefficients.
The band-pass filter 23 has a digital processing function of extracting and outputting a signal of the pitch frequency FF from the acoustic input signal s1 based on the filter coefficient read out from the storage unit 21. The signal extracted by the band-pass filter 23 is output to the harmonic generation section 24.
The harmonic generation unit 24 has a digital processing function of generating harmonic series components (harmonic components) of the signal output from the band-pass filter 23. The signal output from the band-pass filter 23 is a signal having a frequency of 1/2 of the lowest resonance frequency F0, and the N harmonic-overtone component (N is an integer of 3 or more) generated by the harmonic generation unit 24 has a frequency component higher than the lowest resonance frequency F0. The harmonic signal sh having the harmonic train component generated by the harmonic generation unit 24 is output to the addition unit 28.
The adder 28 has a digital processing function of adding the harmonic signal sh to the acoustic input signal s 1. By adding the harmonic signal sh to the acoustic input signal s1, an acoustic output signal s2 including the overtone component is generated. The acoustic output signal s2 generated by the adder 28 is output to the audio output device 3.
In the analog bass processing apparatus 2, since the overtone component of the pitch frequency FF is added to the acoustic input signal s1 and output, even if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the pitch, the user can feel that the audio including the pitch frequency FF is heard. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
1-2 method for determining pitch frequency and method for processing sound
Next, a pitch frequency determination method and an acoustic processing method according to the present embodiment will be described.
Fig. 4 is a flowchart showing a pitch frequency determination method and an acoustic processing method according to embodiment 1.
The pitch frequency determination method is a method of determining a pitch frequency FF when performing an analog bass process on the acoustic input signal s 1.
As a pitch frequency determination method, first, the obtaining unit 10 of the pitch frequency determination device 1 obtains the lowest resonance frequency F0 of the audio output device 3 (step S11). The lowest resonance frequency F0 is input to the obtaining section 10 by, for example, a technician of the sound output device 3.
Next, the determining unit 11 determines the pitch frequency FF based on the lowest resonance frequency F0 obtained by the obtaining unit 10 (step S12). The determination unit 11 in the present embodiment determines the frequency 1/2 of the lowest resonance frequency F0 as the pitch frequency FF.
With this pitch frequency determination method, the pitch frequency FF at the time of performing the analog bass process can be determined easily.
The acoustic processing method is a method of performing an analog bass process on the acoustic input signal s 1.
Steps S11 and S12 of the acoustic processing method are the same as the pitch frequency determination method described above.
In the present embodiment, after steps S11 and S12, the BPF coefficient generating unit 12 generates the filter coefficient of the band-pass filter 23 based on the pitch frequency FF determined by the determining unit 11. The filter coefficients generated by the BPF coefficient generating unit 12 are output to the analog bass processing apparatus 2.
Next, the bandpass filter 23 of the analog bass processing apparatus 2 extracts a signal of the pitch frequency FF from the acoustic input signal S1 (step S13). Specifically, the band-pass filter 23 extracts a signal of the pitch frequency FF from the acoustic input signal s1 by using the filter coefficient generated by the BPF coefficient generating unit 12. Then, the extracted signal of the pitch frequency FF is output to the harmonic generation unit 24.
Next, the overtone 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 an overtone component of the fundamental frequency FF from the signal output from the band-pass filter 23, and outputs the generated overtone component to the addition unit 28.
Next, the harmonic signal sh including the overtone component described above is added to the acoustic input signal S1 (step S15). Accordingly, the acoustic output signal s2 including the signal of the overtone component is generated. The acoustic output signal S2 generated by the adder 28 is output to the acoustic output device 3 (step S16).
By these steps S11 to S16, the overtone component of the fundamental frequency FF is added to the acoustic input signal S1 and output, and thus the user can be made to hear the sound including the fundamental frequency FF in a sense. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
The pitch frequency determination method according to the present embodiment may be implemented by a hardware configuration of the pitch frequency determination device 1 shown in fig. 5. Fig. 5 shows an example of a hardware configuration of a computer 1000 in which the functions of the pitch frequency deciding apparatus 1 are realized by software.
As shown in fig. 5, the computer 1000 is a computer including an input device 1001, an output device 1002, a CPU1003, a built-in storage device 1004, a RAM1005, and a bus 1009. The input device 1001, the output device 1002, the CPU1003, the built-in storage device 1004, and the RAM1005 are connected by a bus 1009.
The input device 1001 is a device that serves as a user interface, such as an input key, a touch panel, and a touch panel display, and accepts an operation by a user who is a technician. The input device 1001 may be configured to receive a remote operation such as a remote control, in addition to a touch operation by a user.
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 and a display, in addition to a signal output terminal.
The built-in storage device 1004 is a flash memory or the like. The built-in storage device 1004 may store a program for realizing the functions of the pitch frequency determination device 1 and/or an application configured by using the functions of the pitch frequency determination device 1.
The RAM1005 is Random Access Memory for storing data and the like when executing a program or an application.
The CPU1003 is Central Processing Unit, copies a program or an application stored in the built-in storage device 1004 to the RAM1005, and sequentially reads out and executes instructions included in the program or the application from the RAM 1005.
[1-3. Effect etc. ]
The pitch frequency determination device 1 of the present embodiment is a pitch frequency determination device that determines a pitch frequency FF when performing an analog bass process on an acoustic input signal s1, and includes: an obtaining unit 10 that obtains a lowest resonance frequency F0 of the audio output device 3 to which the signal subjected to the analog bass process is input; and a determination unit 11 for determining the pitch frequency FF based on the lowest resonance frequency F0.
In this way, the determination unit 11 can determine the pitch frequency FF simply by determining the pitch frequency FF from the lowest resonance frequency F0, which is a physical characteristic of the audio output device 3.
The determination unit 11 may determine the pitch frequency FF as the frequency 1/2 of the lowest resonance frequency.
In this way, the determination unit 11 can determine the pitch frequency FF simply by determining the frequency of 1/2 of the lowest resonance frequency as the pitch frequency FF.
The analog bass processing apparatus 2 according to the present embodiment is an analog bass processing apparatus that performs analog bass processing on an acoustic input signal s1, and includes: a band-pass filter 23 for extracting, from the acoustic input signal s1, the signal of the pitch frequency FF determined by the pitch frequency determining apparatus 1 and outputting the signal; and a harmonic generation unit 24 that generates an overtone component of the signal output from the band-pass filter 23.
In the analog bass processing apparatus 2, since the overtone component of the fundamental frequency FF is added to the acoustic input signal s1 and output, the user can feel that the user hears the sound including the fundamental frequency FF. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
The pitch frequency determination method according to the present embodiment is a method for determining a pitch frequency FF when performing an analog bass process on an acoustic input signal s1, and includes the steps of: a step of obtaining a lowest resonance frequency F0 of the sound output device 3 to which the signal subjected to the analog bass process is input; and determining the pitch frequency FF based on the lowest resonance frequency F0.
This pitch frequency determination method has a step of determining the pitch frequency FF from the lowest resonance frequency F0, which is a physical characteristic of the audio output apparatus 3, and therefore the pitch frequency FF can be determined easily.
The sound processing method according to the present embodiment is a sound processing method for performing an analog bass process on a sound input signal s1, and includes the steps of: a step of obtaining the lowest resonance frequency F0 of the audio output device 3 to which the signal subjected to the analog bass process is input; a step of determining a pitch frequency FF in the analog bass process based on the lowest resonance frequency F0; a step of extracting a signal of a pitch frequency FF from the acoustic input signal s 1; generating a signal of an overtone component of the fundamental frequency FF from the signal of the fundamental frequency FF; and adding the signal of the overtone component to the acoustic input signal s 1.
Since this acoustic processing method has a step of adding the overtone component of the fundamental frequency FF to the acoustic input signal s1, the user can feel that the sound including the fundamental frequency FF is heard. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
[1-4 ] modification of embodiment 1 ]
The configuration of the pitch frequency determining apparatus 1A and the analog bass processing apparatus 2A in the modification of embodiment 1 will be described with reference to fig. 6. In this modification, the filter coefficients of the band pass filter 23 are generated by the analog bass processing device 2A, not by the pitch frequency determining device.
Fig. 6 is a block diagram showing the configuration of the pitch frequency determining apparatus 1A and the analog bass processing apparatus 2A in the modification of embodiment 1.
As shown in fig. 6, the pitch frequency determination device 1A includes: an obtaining section 10 that obtains a lowest resonance frequency F0 of the sound output apparatus 3; and a determining unit 11 for determining the pitch frequency FF.
The obtaining section 10 obtains the lowest resonance frequency F0 of the sound output device 3.
The determining unit 11 has an arithmetic function of determining the pitch frequency FF based on the lowest resonance frequency F0 obtained by the obtaining unit 10. Even in the determination unit 11 according to the modification, the frequency 1/2 of the lowest resonance frequency F0 can be determined as the pitch frequency. In the pitch frequency determining apparatus 1A, the pitch frequency FF can be determined simply by the calculation of the determining unit 11.
The pitch frequency FF determined by the determining unit 11 is output to the analog bass processing apparatus 2A. The pitch frequency FF may be output to the analog bass processing apparatus 2A through a recording medium such as a USB memory, for example, or may be output to the analog bass processing apparatus 2A by directly connecting the pitch frequency determining apparatus 1A to the analog bass processing apparatus 2A.
As shown in fig. 6, the analog bass processing apparatus 2A includes: the storage unit 21, the BPF coefficient generation unit 22 that generates the band-pass filter coefficient, the band-pass filter 23, the harmonic generation unit 24, and the addition unit 28.
The storage unit 21 is a nonvolatile memory that stores the pitch frequency FF determined by the determination unit 11.
The BPF coefficient generation unit 22 has an arithmetic function of generating a filter coefficient of the band-pass filter 23 based on the pitch frequency FF read from the storage unit 21. The filter coefficient generated by the BPF coefficient generation unit 22 is output to the band-pass filter 23.
The band-pass filter 23 has a digital processing function of extracting and outputting a signal of the pitch 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 band-pass filter 23 is output to the harmonic generation section 24.
The harmonic generation unit 24 has a digital processing function of generating overtone components of the signal output from the band-pass filter 23. The harmonic signal sh having the harmonic train component generated by the harmonic generation unit 24 is output to the addition unit 28.
The adder 28 has a digital processing function of adding the harmonic signal sh to the acoustic input signal s 1. By adding the harmonic signal sh to the acoustic input signal s1, an acoustic output signal s2 including the overtone component is generated. The acoustic output signal s2 generated by the adder 28 is output to the audio output device 3.
Even in the analog bass processing apparatus 2A, since the overtone component of the fundamental tone frequency FF is added to the acoustic input signal s1 and output, if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the fundamental tone, the user can feel the audio including the fundamental tone frequency FF. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
(embodiment 2)
[2-1. Pitch frequency determination device and Structure of analog Bass processing device ]
The configuration of the pitch frequency determination device 1B and the analog bass processing device 2B in embodiment 2 will be described with reference to fig. 7 and 8. In embodiment 2, an example will be described 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 band-pass filter 23.
Fig. 7 is a block diagram showing the structures of the pitch frequency determining apparatus 1B and the analog bass processing apparatus 2B in embodiment 2. Fig. 7 also shows the sound output device 3 connected to the analog bass processing device 2B.
As shown in fig. 7, the pitch frequency determination device 1B includes: an obtaining unit 10 that obtains the lowest resonance frequency F0 and the attenuation characteristic c1 of the resonance frequency of the audio output device 3, a storage unit 15 that stores the amplification amount b1 in the low frequency domain of the audio input signal s1, a determination unit 11 that determines the pitch frequency FF, a BPF coefficient generation unit 12 that generates a band-pass filter coefficient, and an LBF (low frequency domain amplification filter) coefficient generation unit 16 that generates a low frequency domain amplification filter coefficient.
The obtaining section 10 obtains the lowest resonance frequency F0 of the sound output device 3 and the attenuation characteristic c1.
Fig. 8 shows the lowest resonance frequency F0, the attenuation characteristic c1, and the pitch frequency FF when the analog bass process is performed in the audio output apparatus 3.
The attenuation characteristic c1 is a characteristic showing a tendency of attenuation (a predetermined attenuation rate) in a frequency band lower than the lowest resonance frequency F0 of the audio output device 3. The attenuation characteristic c1 is a characteristic inherent to the sound output device 3, and can take various values depending on the size or material of the sound output device 3. In this embodiment, for example, the lowest resonance frequency F0 is 90Hz, and the attenuation characteristic c1 is-24 dB/oct.
The lowest resonance frequency F0 and the attenuation characteristic c1 are input to the obtaining unit 10 by, for example, a technician who develops the audio output device 3. The obtaining unit 10 may receive an input of a resonance frequency characteristic (see a thick broken line in fig. 8) plotted as a graph, and may obtain the lowest resonance frequency F0 and the attenuation characteristic c1 by calculating the received resonance frequency characteristic.
The storage unit 15 is a memory for storing the amplification amount b1 in the low frequency range of the acoustic input signal s 1. The purpose of amplifying the signal in the low frequency region of the acoustic input signal s1 is to amplify the frequency components in the vicinity of the lowest resonance frequency F0, thereby making it possible to make the lowest resonance frequency F0 appear to deviate from the low frequency region. By shifting the lowest resonance frequency F0 to the low frequency domain, the pitch frequency FF can be lowered further to the low frequency domain side, and thus the user can be made to hear the sound including the lower pitch frequency FF in a sense.
The amplification amount b1 is, for example, 6dB, 3dB, 9dB, or the like, and in the present embodiment, the amplification amount b1 is 6dB. In this example, the amount of amplification b1 stored in the storage unit 15 is set to 6dB, but this value is not necessarily required. However, if the amplification amount b1 is extremely set to a large value (for example, 18dB or the like), distortion occurs in a signal in the low frequency domain amplification filter 27 described later, and therefore the amplification amount b1 is preferably 9dB or less.
The amplified 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 has an arithmetic function of determining the pitch frequency FF from the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b 1. The determination unit 11 obtains, from the attenuation characteristic c1, a frequency Fd at which the value of the gain reduction amount for the gain in the lowest resonance frequency F0 is equal to the value of the amplification amount b 1. The frequency Fd is a frequency at which the lowest resonance frequency F0 appears to be shifted to a low frequency.
Fig. 8 shows the frequency Fd at which the amount of gain reduction becomes 6dB for the gain in the lowest resonance frequency F0. In the present embodiment, since the attenuation characteristic c1 is-24 dB/oct, the frequency Fd whose reduction is 6dB is a frequency 1/4 lower by eight degrees when viewed from the lowest resonance frequency F0, and is 75.68Hz.
The determination unit 11 determines a frequency 1/2 of the frequency Fd as the pitch frequency FF. The pitch frequency FF in the above example is 37.84Hz. The pitch frequency determining device 1B can simply determine the pitch frequency FF by the calculation of the determining unit 11. In addition, since the signal at the frequency Fd and the frequency around the frequency Fd is amplified by the low-frequency-domain amplifying filter 27 to be described later, the frequency Fd appears to be shifted to the low frequency domain and becomes the lowest resonance frequency.
The BPF coefficient generation unit 12 has an arithmetic function of generating a filter coefficient of the band-pass filter 23 based on the pitch frequency FF determined by the determination unit 11. The LBF coefficient generation unit 16 has an arithmetic function of generating a filter coefficient of the low-frequency-domain amplification filter 27 from the amplification amount b1 stored in the storage unit 15. The filter coefficients 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 analog bass processing apparatus 2B. These filter coefficients may be output to the analog bass processing apparatus 2B via a recording medium such as a USB memory, for example, or may be output to the analog bass processing apparatus 2B by directly connecting the pitch frequency determining apparatus 1B to the analog bass processing apparatus 2B.
As shown in fig. 7, the analog bass processing apparatus 2B includes a storage unit 21, a band-pass filter 23, a harmonic generation unit 24, a low-frequency-domain amplification filter 27, and an addition unit 28.
The storage unit 21 is a nonvolatile memory that stores the filter coefficients generated by the BPF coefficient generation unit 12 and the filter coefficients generated by the LBF coefficient generation unit 16. The filter coefficients generated by the BPF coefficient generating unit 12 are read by the band pass filter 23, and the filter coefficients generated by the LBF coefficient generating unit 16 are read by the low frequency domain amplifying filter 27.
The band-pass filter 23 has a digital processing function of extracting and outputting a signal of the pitch frequency FF from the acoustic input signal s1 based on the filter coefficient generated by the BPF coefficient generating section 12. The signal extracted by the band-pass filter 23 is output to the harmonic generation section 24.
The harmonic generation unit 24 has a digital processing function of generating overtone components of the signal output from the band-pass filter 23. The harmonic signal sh having the harmonic train component generated by the harmonic generation unit 24 is output to the low-frequency-domain amplifying filter 27.
The low-frequency-domain amplifying filter 27 amplifies the harmonic signal sh based on the filter coefficient generated by the LBF coefficient generating section 16. At this time, the low-frequency-domain amplifying filter 27 amplifies the harmonic signal sh by at least an amplification amount b 1. The amplified signal sb amplified by the low-frequency-domain amplifying filter 27 is output to the adder 28.
The harmonic signal sh is amplified by the low-frequency-domain amplification filter 27 for the following reasons. The signal output from the band-pass filter 23 is a signal having a frequency of 1/2 of the frequency Fd, and therefore the overtone component thereof appears to be a frequency equal to or higher than the lowest resonance frequency shifted to the low frequency domain, but also includes a frequency component lower than the lowest resonance frequency F0. Therefore, by amplifying the harmonic signal sh with the low-frequency-domain amplifying filter 27, it is possible to suppress degradation of the output of the frequency component lower than the lowest resonance frequency F0.
The adder 28 has a digital processing function of adding the amplified signal sb to the acoustic input signal s 1. By adding the amplified signal sb to the acoustic input signal s1, an amplified acoustic output signal s2 including the overtone component is generated. The acoustic output signal s2 generated by the adder 28 is output to the audio output device 3.
Even in the analog bass processing apparatus 2B, since the overtone component of the fundamental tone frequency FF is added to the acoustic input signal s1 and output, if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the fundamental tone, the user can feel the audio including the fundamental tone frequency FF. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
The pitch frequency determining apparatus 1B further includes a storage unit 15 for storing the amplification amount B1 in the low frequency range of the acoustic input signal s 1. The obtaining unit 10 may further obtain the attenuation characteristic c1 in a frequency band lower than the lowest resonance frequency F0 of the audio output apparatus 3, and the determining unit 11 may determine the pitch frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b 1.
In this way, the determination unit 11 can determine the pitch frequency FF simply by determining the pitch frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1, which are physical characteristics of the audio output apparatus 3.
The determination unit 11 may determine the frequency Fd when the value of the gain reduction amount for the gain in the lowest resonance frequency F0 becomes equal to the value of the amplification amount b1 from the attenuation characteristic c1, and determine the frequency of 1/2 of the frequency Fd as the pitch frequency FF.
Accordingly, the lowest resonance frequency that appears can be shifted to the low frequency domain, and therefore the pitch frequency FF can be lowered to the lower frequency domain side. Accordingly, the user can be made to feel that the sound including the lower pitch frequency FF is heard, and the sound quality of the sound output from the sound output device 3 can be improved.
The analog bass processing apparatus 2B according to the present embodiment is an analog bass processing apparatus that performs analog bass processing on an acoustic input signal s1, and includes: a band-pass filter 23 for extracting the signal of the pitch frequency FF determined by the pitch frequency determining device 1B from the acoustic input signal s1 and outputting the signal; a harmonic generation unit 24 that generates an overtone component of the signal output from the band-pass filter 23; and a low-frequency-domain amplification filter 27 that amplifies the signal generated by the harmonic generation unit 24 by at least an amplification amount b 1.
In the analog bass processing apparatus 2B, since the overtone component of the fundamental frequency FF is also added to the acoustic input signal s1 and output, the user can feel that the user hears the sound including the fundamental frequency FF. Further, since the harmonic signal sh is amplified by the low-frequency-domain amplification filter 27, degradation of the output of the frequency component lower than the lowest resonance frequency F0 can be suppressed. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
[2-2. Modification of embodiment 2 ]
The configuration of the pitch frequency determining apparatus 1C and the analog bass processing apparatus 2C in the modification of embodiment 2 will be described with reference to fig. 9. In this modification, the filter coefficients of the band pass filter 23 and the filter coefficients of the low frequency domain amplifying filter 27 are generated not by the pitch frequency determining device but by the analog bass processing device 2C.
Fig. 9 is a block diagram showing the configuration of the pitch frequency determining apparatus 1C and the analog bass processing apparatus 2C in the modification of embodiment 2.
As shown in fig. 9, the pitch frequency determination device 1C includes: an obtaining unit 10 that obtains a lowest resonance frequency F0 and an attenuation characteristic c1 of the sound output device 3; a storage unit 15 for storing the amplification amount b1 in the low frequency range of the audio input signal s 1; and a determination unit 11 for determining the pitch frequency FF.
The obtaining section 10 obtains the lowest resonance frequency F0 of the sound output device 3 and the attenuation characteristic c1.
The storage unit 15 is a memory for storing the amplification amount b1 in the low frequency range of the acoustic input signal s 1. The amplified amount b1 stored in the storage unit 15 is output to the determination unit 11 and the storage unit 21.
The determining unit 11 has an arithmetic function of calculating the pitch frequency FF from the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b 1. The determination unit 11 obtains, from the attenuation characteristic c1, a frequency Fd at which the value of the gain reduction amount for the gain in the lowest resonance frequency F0 is equal to the value of the amplification amount b 1.
The determination unit 11 determines a frequency 1/2 of the frequency Fd as the pitch frequency FF. The pitch frequency determining device 1C can simply determine the pitch frequency FF by the calculation of the determining unit 11.
The pitch frequency FF determined by the determining unit 11 and the amplification amount b1 stored in the storage unit 15 are output to the analog bass processing apparatus 2C. The pitch frequency FF may be output to the analog bass processing apparatus 2C via a recording medium such as a USB memory, for example, or may be output to the analog bass processing apparatus 2C by directly connecting the pitch frequency determining apparatus 1C to the analog bass processing apparatus 2C.
As shown in fig. 9, the analog bass processing apparatus 2C includes: the storage unit 21, the BPF coefficient generation unit 22 that generates the band-pass filter coefficient, the band-pass filter 23, the harmonic generation unit 24, the LBF coefficient generation unit 26 that generates the low-frequency-domain amplified filter coefficient, the low-frequency-domain amplified filter 27, and the addition unit 28.
The storage unit 21 is a nonvolatile memory that stores the pitch 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 has an arithmetic function of generating a filter coefficient of the band-pass filter 23 based on the pitch frequency FF stored in the storage unit 21. The filter coefficient generated by the BPF coefficient generation unit 22 is output to the band-pass filter 23.
The LBF coefficient generation unit 26 has an arithmetic function of generating a filter coefficient of the low-frequency-domain amplification filter 27 from the amplification amount b1 stored in the storage unit 21. The filter coefficient generated by the LBF coefficient generating section 26 is output to the low frequency domain amplifying filter 27.
The band-pass filter 23 has a digital processing function of extracting and outputting a signal of the pitch 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 band-pass filter 23 is output to the harmonic generation section 24.
The harmonic generation unit 24 has a digital processing function of generating overtone components of the signal output from the band-pass filter 23. The harmonic signal sh having the harmonic train component generated by the harmonic generation unit 24 is output to the low-frequency-domain amplifying filter 27.
The low-frequency-domain amplifying filter 27 amplifies the harmonic signal sh based on the filter coefficient generated by the LBF coefficient generating section 26. The amplified signal sb amplified by the low-frequency-domain amplifying filter 27 is output to the adder 28.
The adder 28 has a digital processing function of adding the amplified signal sb to the acoustic input signal s 1. By adding the amplified signal sb to the acoustic input signal s1, an acoustic output signal s2 including the overtone component and amplified is generated. The acoustic output signal s2 generated by the adder 28 is output to the audio output device 3.
Even in the analog bass processing apparatus 2C, since the overtone component of the fundamental tone frequency FF is added to the acoustic input signal s1 and output, if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the fundamental tone, the user can feel that the audio including the fundamental tone frequency FF is heard. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
Embodiment 3
[3-1. Pitch frequency determination device and Structure of analog Bass processing device ]
The configuration of the pitch frequency determining apparatus 1D and the analog bass processing apparatus 2D in embodiment 3 will be described with reference to fig. 10. In the example described in embodiment 3, the amplified amount b1 is obtained by the obtaining unit 10, not by being stored in the storage unit.
Fig. 10 is a block diagram showing the configuration of the pitch frequency determining apparatus 1D and the analog bass processing apparatus 2D in embodiment 3. Fig. 10 also shows the sound output device 3 connected to the analog bass processing device 2D.
As shown in fig. 10, the pitch frequency determination device 1D includes: an obtaining unit 10 that obtains a lowest resonance frequency F0, attenuation characteristic c1, and amplification amount b1 of the sound output device 3; a determination unit 11 that determines a pitch frequency FF; a BPF coefficient generation unit 12 that generates a band-pass filter coefficient; and an LBF coefficient generating section 16 that generates a low frequency domain amplified filter coefficient.
The obtaining unit 10 obtains the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1 in the low frequency domain of the acoustic input signal s1 of the acoustic output device 3.
The determination unit 11 has an arithmetic function of determining the pitch frequency FF from the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1. The determination unit 11 obtains, from the attenuation characteristic c1, a frequency Fd at which the value of the gain reduction amount for the gain in the lowest resonance frequency F0 is equal to the value of the amplification amount b1.
The determination unit 11 determines a frequency 1/2 of the frequency Fd as the pitch frequency FF. In the pitch frequency determination device 1D, the pitch frequency FF can be determined simply by the calculation of the determination unit 11.
The BPF coefficient generation unit 12 has an arithmetic function of generating a filter coefficient of the band-pass filter 23 based on the pitch frequency FF determined by the determination unit 11. The LBF coefficient generation unit 16 has an arithmetic function of generating a filter coefficient of the low-frequency-domain amplification filter 27 from the amplification amount b1 obtained by the obtaining unit 10. The filter coefficient generated by the BPF coefficient generating unit 12 and the filter coefficient generated by the LBF coefficient generating unit 16 are output to the analog bass processing apparatus 2D.
As shown in fig. 10, the analog bass processing apparatus 2D includes: a storage unit 21, a band-pass filter 23, a harmonic generation unit 24, a low-frequency-domain amplifying filter 27, and an addition unit 28. Since these constituent elements are the same as those of embodiment 2, the description thereof will be omitted.
Even in the analog bass processing apparatus 2D, since the overtone component of the fundamental tone frequency FF is added to the acoustic input signal s1 and output, if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the fundamental tone, the user can feel that the audio including the fundamental tone frequency FF is heard. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
The obtaining unit 10 may further obtain the attenuation characteristic c1 in a frequency band lower than the lowest resonance frequency F0 of the audio output device 3 and the amplification amount b1 in the low frequency band of the audio input signal s1, and the determining unit 11 may determine the pitch frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b 1.
In this way, the determination unit 11 can determine the pitch frequency FF simply by determining the pitch frequency FF based on the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1, which are physical characteristics of the audio output apparatus 3.
The determination unit 11 may determine, based on the attenuation characteristic c1, a frequency Fd at which the gain of the lowest resonance frequency F0 is reduced by the gain equal to the amplification amount b1, and determine a frequency 1/2 of the frequency Fd as the pitch frequency FF.
Accordingly, the lowest resonance frequency that appears can be shifted to the low frequency domain, and therefore the pitch frequency FF can be lowered to the lower frequency domain side. Accordingly, the user can feel that the sound including the lower pitch frequency FF is heard, and the sound quality of the sound output from the sound output device 3 can be improved.
[3-2. Modification of embodiment 3 ]
The configuration of the pitch frequency determining apparatus 1E and the analog bass processing apparatus 2E in the modification of embodiment 3 will be described with reference to fig. 11. In the example described in this modification, the filter coefficients of the band pass filter 23 and the filter coefficients of the low frequency domain amplifying filter 27 are generated not by the pitch frequency determining device but by the analog bass processing device 2E.
Fig. 11 is a block diagram showing the configuration of a pitch frequency deciding apparatus 1E and an analog bass processing apparatus 2E in a modification of embodiment 3.
As shown in fig. 11, the pitch frequency determination device 1E includes: an obtaining unit 10 that obtains a lowest resonance frequency F0, attenuation characteristic c1, and amplification amount b1 of the sound output device 3; and a determination unit 11 for determining the pitch frequency FF.
The obtaining section 10 obtains the lowest resonance frequency F0 of the sound output device 3, the attenuation characteristic c1, and the amplification amount b1 in the low frequency domain of the acoustic input signal s 1. The lowest resonance frequency F0 and the attenuation characteristic c1 obtained by the obtaining unit 10 are output to the determining unit 11, and the amplification amount b1 is output to the determining unit 11 and the analog bass processing apparatus 2E.
The determining unit 11 has an arithmetic function of calculating the pitch frequency FF from the lowest resonance frequency F0, the attenuation characteristic c1, and the amplification amount b1. The determination unit 11 obtains, from the attenuation characteristic c1, a frequency Fd at which the value of the gain reduction amount for the gain in the lowest resonance frequency F0 is equal to the value of the amplification amount b1.
The determination unit 11 determines a frequency 1/2 of the frequency Fd as the pitch frequency FF. The pitch frequency determining device 1E can simply determine the pitch frequency FF by the calculation of the determining unit 11.
The pitch frequency FF determined by the determining unit 11 and the amplification amount b1 obtained by the obtaining unit 10 are output to the analog bass processing apparatus 2E.
As shown in fig. 11, the analog bass processing apparatus 2E includes: the storage unit 21, the BPF coefficient generation unit 22 that generates the band-pass filter coefficient, the band-pass filter 23, the harmonic generation unit 24, the LBF coefficient generation unit 26 that generates the low-frequency-domain amplified filter coefficient, the low-frequency-domain amplified filter 27, and the addition unit 28.
The storage unit 21 stores the pitch 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 a filter coefficient of the band-pass filter 23 based on the pitch frequency FF stored in the storage unit 21. The LBF coefficient generation unit 26 generates a filter coefficient of the low-frequency-domain amplification filter 27 from the amplification amount b1 stored in the storage unit 21. The following components are the same as those in the modification of embodiment 2, and therefore, description thereof will be omitted.
Even in the analog bass processing apparatus 2E, since the overtone component of the fundamental tone frequency FF is added to the acoustic input signal s1 and output, if the audio output apparatus 3 is an apparatus that cannot reproduce the frequency component that becomes the fundamental tone, the user can feel that the audio including the fundamental tone frequency FF is heard. Accordingly, the quality of the sound output from the sound output device 3 can be improved.
(other embodiments)
The pitch frequency determining device and the like of the present disclosure have been described above based on the embodiments and the like, and the present disclosure is not limited to these embodiments. For example, other embodiments in which the components described in the present specification are arbitrarily combined and a plurality of the components are removed may be also embodiments of the present disclosure. Further, modified examples obtained by performing various modifications, which can be conceived by those skilled in the art, on the above-described embodiments within a range not departing from the gist of the present disclosure, that is, the content described in the independent claims are also included in the present disclosure.
Also, the following illustrated aspects may be included within the scope of one or more aspects of the present disclosure.
(1) Some of the components constituting the pitch frequency determining apparatus and the like may be a computer system including a microprocessor, a ROM, a RAM, a hard disk unit, a display unit, a keyboard, a mouse, and the like. The RAM or the hard disk unit stores a computer program. The microprocessor performs its functions by operating in accordance with the computer program. The computer program is composed of a plurality of command codes for issuing instructions to a computer in order to realize predetermined functions.
(2) Some of the constituent elements constituting the pitch frequency determining apparatus and the like may be 1 system LSI (Large Scale Integration: large scale integrated circuit). The system LSI is a super-multifunctional LSI having a plurality of components integrated and manufactured on one chip, and specifically is a computer system including a microprocessor, a ROM, a RAM, and the like. The RAM has a computer program stored therein. The microprocessor operates according to the computer program, whereby the system LSI realizes its functions.
(3) A part of the components constituting the pitch frequency determining device and the like may be formed 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, ROM, RAM, etc. The IC card or the module may include the above-described ultra-multifunctional LSI. The microprocessor is operated by following a computer program so that the IC card or the module realizes its functions. The IC card or the module may also be tamper resistant.
(4) The above-described components constituting the pitch frequency determining apparatus and the like may be implemented as a computer-readable recording medium on which the computer program or the digital signal is recorded, such as a floppy disk, a hard disk, a CD-ROM, MO, DVD, DVD-ROM, a DVD-RAM, a BD (Blu-ray (registered trademark) Disc), a semiconductor memory, or the like. Further, the digital signal recorded in these recording media may be realized.
The computer program or the digital signal may be transmitted via a telecommunication line, a wireless or wired communication line, a network typified by the internet, or data playback, or the like, as a part of the components constituting the pitch frequency determining apparatus and the like.
(5) The present disclosure may also be implemented as the method described above. The present invention can be implemented as a computer program for implementing these methods by a computer, or as a digital signal composed of the computer program.
(6) The present disclosure may be a computer system including a microprocessor and a memory, wherein the memory stores the computer program, and the microprocessor operates according to the computer program.
(7) The program or the digital signal may be transferred by being recorded on the recording medium, or may be transferred via the network or the like, and may be executed by a separate other computer system.
(8) The above embodiments and the above modifications may be combined, respectively.
The pitch frequency determination device of the present disclosure is suitable for use in determining pitch frequencies when performing analog bass processing in devices such as televisions, car stereos, smartphones, tablet computers, portable speakers, headphones, earphones, and audio speakers.
Claims (6)
1. A pitch frequency determining device determines a pitch frequency when an analog bass process is performed on an acoustic input signal,
the pitch frequency determination device is provided with:
an obtaining unit that obtains a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; and
a determining unit configured to determine the pitch frequency based on the lowest resonance frequency,
the obtaining section also obtains attenuation characteristics in a frequency band of the sound output apparatus lower than the lowest resonance frequency and an amplification amount in a low frequency domain of the acoustic input signal,
the determination unit determines, when the pitch frequency is determined based on the lowest resonance frequency, the attenuation characteristic, and the amplification amount, a frequency at which a value of a gain reduction amount with respect to a gain in the lowest resonance frequency is equal to a value of the amplification amount, based on the attenuation characteristic, and determines a frequency of 1/2 of the frequency as the pitch frequency.
2. A pitch frequency determining device determines a pitch frequency when an analog bass process is performed on an acoustic input signal,
the pitch frequency determination device is provided with:
an obtaining unit that obtains a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; and
A determining unit configured to determine the pitch frequency based on the lowest resonance frequency,
the pitch frequency determination device further includes a storage unit that stores an amplification amount in a low frequency region of the acoustic input signal,
the obtaining section further obtains attenuation characteristics in a frequency band of the sound output device lower than the lowest resonance frequency,
the determination unit determines, when determining the pitch frequency based on the lowest resonance frequency, the attenuation characteristic, and the amplification amount, a frequency at which a value of a gain reduction amount with respect to a gain in the lowest resonance frequency is equal to a value of the amplification amount based on the attenuation characteristic, and determines a frequency of 1/2 of the frequency as the pitch frequency.
3. An analog bass processing device for performing analog bass processing on an acoustic input signal,
the analog bass processing apparatus includes:
a band-pass filter for extracting the signal of the pitch frequency determined by the pitch frequency determining device according to claim 1 or 2 from the acoustic input signal and outputting the extracted signal; and
and a harmonic generation unit that generates an overtone component of the signal output from the band-pass filter.
4. An analog bass processing device for performing analog bass processing on an acoustic input signal,
the analog bass processing apparatus includes:
a band-pass filter for extracting the signal of the pitch frequency determined by the pitch frequency determining device according to claim 1 or 2 from the acoustic input signal and outputting the extracted signal;
a harmonic generation unit that generates an overtone component of the signal output from the band-pass filter; and
and a low-frequency-domain amplification filter that amplifies the signal generated by the harmonic generation unit by at least the amplification amount.
5. A pitch frequency determining method determines a pitch frequency when an analog bass process is performed on an acoustic input signal,
the pitch frequency determination method includes the steps of:
a step of storing an amplification amount in a low frequency domain of the acoustic input signal;
a step of obtaining a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input; and
a step of determining the pitch frequency based on the lowest resonance frequency,
in the step of obtaining the lowest resonance frequency, attenuation characteristics in a frequency band lower than the lowest resonance frequency of the sound output device are also obtained,
In the step of determining the pitch frequency, when the pitch frequency is determined based on the lowest resonance frequency, the attenuation characteristic, and the amplification amount, a frequency at which a value of a gain reduction amount with respect to a gain in the lowest resonance frequency is equal to a value of the amplification amount is obtained based on the attenuation characteristic, and a frequency of 1/2 of the frequency is determined as the pitch frequency.
6. A sound processing method for performing analog bass processing on sound input signals,
the sound processing method comprises the following steps:
a step of storing an amplification amount in a low frequency domain of the acoustic input signal;
a step of obtaining a lowest resonance frequency of a sound output device to which the signal subjected to the analog bass process is input;
determining a pitch frequency in the analog bass process based on the lowest resonance frequency;
extracting the signal of the fundamental tone frequency from the acoustic input signal;
generating a signal of an overtone component of the fundamental tone frequency from the signal of the fundamental tone frequency; and
a step of adding the signal of the overtone component to the acoustic input signal,
In the step of obtaining the lowest resonance frequency, attenuation characteristics in a frequency band lower than the lowest resonance frequency of the sound output device are also obtained,
in the step of determining the pitch frequency, when the pitch frequency is determined based on the lowest resonance frequency, the attenuation characteristic, and the amplification amount, a frequency at which a value of a gain reduction amount with respect to a gain in the lowest resonance frequency is equal to a value of the amplification amount is obtained based on the attenuation characteristic, and a frequency of 1/2 of the frequency is determined as the pitch frequency.
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| Publication number | Publication date |
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| JP2021048553A (en) | 2021-03-25 |
| CN111968672A (en) | 2020-11-20 |
| JP7379988B2 (en) | 2023-11-15 |
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