JP2002006852A - Speech signal generating method, speech signal generator and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate natural pseudo bass while preventing the abrupt changes in sound quality with respect to the changes of pitch of a portable telephone, electronic musical instrument, etc. SOLUTION: A pseudo bass signal is formed in synchronization with an ordinary musical tone signal. The level of the pseudo bass signal is adjusted by multiplication of a sound volume coefficient RVOL shown in Figure 14. The characteristics of the sound volume coefficient RVOL are set so as to gradually increase the level of the pseudo bass as frequencies are lower before and after the cutoff frequency of a speaker of the portable telephone, etc., like the same figure and therefore such a state that the pseudo bass is suddenly generated at the certain pitch and the sound quality is changed may be relieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio signal generating method, an audio signal generating device, and a recording medium used in a device for generating a musical tone signal, such as a portable telephone, an electronic musical instrument, and an amusement device. The present invention relates to an audio signal generation method, an audio signal generation device, and a recording medium that are suitable for use in a device.

[0002]

2. Description of the Related Art In an electronic musical instrument, a portable telephone, an amusement device, and the like, a musical tone signal is generated via a built-in or external electro-acoustic transducer (such as a speaker). Here, the range of sound that can be converted has a predetermined limit. In particular,
With respect to bass, only sounds up to the lowest frequency defined by the lowest resonance frequency of the electroacoustic transducer (hereinafter, referred to as the "lowest frequency") can be produced.

[0003] In order to solve this, a technique for generating a "pseudo bass" is known. This is a technique using the illusion of a human being that when a sound signal having two frequencies is generated, a signal corresponding to the greatest common divisor of both is heard. For example, to generate a 100 Hz “pseudo bass” by a speaker that cannot output a 100 Hz audio signal, “200 Hz and 300 Hz” and “300 Hz and 40 Hz” are used.
It is preferable to generate two frequencies, such as "0 Hz", whose greatest common divisor is 100 Hz.

[0004] For example, US Pat. No. 5,930,373 discloses the details of the technology. In this technique, components that cannot be reproduced by a speaker in a digital audio signal sequentially supplied are subjected to a filtering process, and frequency components twice, three times,... Of these components are generated. The frequency component generated in this way and the original audio signal are added, and sound is generated via a speaker. Also,
Japanese Patent Application No. 2000-159478 (not disclosed) by the present applicant describes a technique in which pseudo low sound waveform data is generated in advance and stored in a waveform memory together with normal tone waveform data. In this technique, a tone signal is generated by reading only normal tone waveform data in a high tone range, while a normal tone waveform data and a pseudo low tone waveform data are read in a low tone range, and a tone signal is generated by mixing the two. Is disclosed.

[0005]

In the above technology,
Whether or not to generate the pseudo bass is determined based on whether or not the pitch of the tone signal is equal to or lower than a predetermined minimum frequency (for example, a cutoff frequency). However, such a technique has a problem in that the sound quality may be significantly different before and after the lowest frequency, and a sense of incongruity occurs. The present invention has been made in view of the above circumstances, and has as its object to provide an audio signal generation method, an audio signal generation device, and a recording medium that can generate a pseudo bass sound in a natural state.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following constitution. Note that the contents in parentheses are examples. In the configuration according to the first aspect, the second audio signal including the pseudo bass corresponding to the first audio signal is provided.
Generating a second audio signal for generating an audio signal;
A coefficient generation step (step SP33) of generating a coefficient (volume coefficient RVOL) that gradually decreases as the frequency of the second audio signal increases in a predetermined range (lowest frequency to pseudo-bass start frequency) of the audio signal; A level control step of controlling the level of the second audio signal according to the coefficient (step SP36); and an output step of outputting the second audio signal in synchronization with the first audio signal (step SP38). It is characterized by. Further, in the configuration according to claim 2, in the audio signal generating method according to claim 1, the audio signal generating step includes: assigning a sound channel to the second audio signal in a sound source (step SP32); Setting a tone parameter corresponding to the first audio signal in the sound channel (step SP36), and in the output step, issuing a sound instruction to the sound channel. Furthermore, in the configuration according to claim 3, in the audio signal generation method according to claim 1, the first audio signal is an audio signal sequentially supplied, and the second audio signal generation step includes:
It is characterized by having a step of extracting a fundamental wave component from the first audio signal (fundamental wave extracting section 93) and a step of generating a harmonic of the fundamental wave component (equal loudness generating section 96). According to a fourth aspect of the present invention, the method according to any one of the first to third aspects is performed. According to a fifth aspect of the present invention, a program for executing the method according to any one of the first to third aspects is stored.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION First embodiment 1.1. Principle of Embodiment 1.1.1. Analysis of Waveform Components In the present embodiment, the musical tone waveform is stored separately as a “periodic component” and a “noise component”, and thus details thereof will be described. FFT sound waveform of natural musical instrument
When analyzed (Fast Fourier Transform), the frequency component of the musical sound waveform can be separated into a frequency component continuous on the time axis and a frequency component intermittent on the time axis. When the waveform is synthesized based on the former frequency component, a "periodic component" of a musical sound waveform is obtained, and when the waveform is synthesized based on the latter frequency component, a "noise component" of the musical sound waveform is obtained.

One example is shown in FIG. FIG. 7A shows a musical sound waveform (original waveform) of a saxophone. FIG. 4B shows the periodic component, and FIG. 4C shows the noise component. As can be seen from these figures, the interval where the noise component has a large amplitude level is short, and is often dispersed over a wider frequency range than the periodic component of the tone signal. For this reason, it is rare that the characteristics of the electro-acoustic transducer become a problem, and it is understood that it is sufficient to generate a pseudo bass only for the periodic component as needed.

1.1.2. Equal loudness curve In human hearing, even if the sound pressure level is constant, it seems that the sense of volume is different if the frequency is different. Therefore, when a curve of sound pressure level is drawn on the graph in which the horizontal axis is frequency and the vertical axis is sound pressure level, the loudness (loudness) becomes equal, as shown in FIGS. 5 (a) and 5 (b). Such characteristics are obtained. These characteristics are called "equal loudness curves". FIG. 2 (a) is called "Fletcher &Manson's equal loudness curve" and is slightly older. FIG. 2B is called "Robinson &Dadson's equal loudness curve", and is relatively new and adopted in ISO.

1.2. Next, a hardware configuration of the mobile phone according to the first embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 2 denotes a communication unit, which performs wireless communication with a base station (not shown).
Reference numeral 4 denotes a coder / decoder, which encodes and decodes signals transmitted and received in the communication unit 2. Reference numeral 3 denotes a microphone that detects a user's voice. Reference numeral 6 denotes a display, which displays various kinds of information to a user. Reference numeral 8 denotes an input device, which includes a numeric keypad, directional buttons, and the like, and is used by a user to input various types of information. Reference numeral 10 denotes a sound source, which generates a tone signal such as a ring tone based on the supplied performance information. In the present embodiment, the sound source 10 is constituted by a waveform memory sound source. The generated tone signal is generated via the sound system 12.
Note that the sound system 12 includes an amplifier and an electroacoustic transducer. Speakers, headphones, earphones, and the like can be selected as the electroacoustic transducer, and these have different conversion characteristics.

Reference numeral 16 denotes a MIDI interface for exchanging MIDI signals with an external MIDI device. A vibrator 18 vibrates the mobile phone when the mobile phone is set to the silent mode. Reference numeral 20 denotes a CPU, which controls each unit in the mobile phone via the bus 14 based on a control program described later. 22 is a ROM, an operating system,
It stores a tone synthesis program, default performance information of a mobile phone, and various other data. 24 is a RAM, CP
It is used as a work memory of the U20, and can store user-defined performance information. The waveform memory in the sound source 10 is backed up by a battery, and can store waveform data of a user-defined tone color and the like.

1.3. Operation of Embodiment 1.3.1. Waveform Data Creation Processing The waveform data used in the present embodiment can be created by a portable telephone manufacturer or user by a personal computer or the like. The contents of the processing will be described with reference to FIG. FIG. 3 is a functional block diagram showing the contents of a processing program executed in the personal computer.

In FIG. 1, reference numeral 30 denotes material waveform data such as a recording waveform of a musical tone of a natural musical instrument, which is input from the outside to a personal computer via a sound board, a removable disk, a network, or the like. Reference numeral 40 denotes a waveform analysis unit, which classifies the frequency components of the material waveform data 30 into components that are continuous on the time axis (deterministic frequency components) and other discrete components (noise components). Here, the details of the waveform analyzer 40 will be described with reference to FIG. 42 is an FF inside the waveform analysis unit 40.
A T-analysis processing unit that performs an FFT analysis process on the material waveform data 30. Here, first, a window function having a length eight times the pitch period is applied to the material waveform data 30, and the frequency components within the range of the window function are analyzed.

Next, the position of the window function is shifted backward by 1/8 of the pitch period on the time axis, and the frequency components are similarly analyzed. When this process is repeated for the entire original waveform data, a change in the frequency component on the time axis is obtained. Reference numeral 44 denotes a continuous component separation unit, which separates a continuous component on the time axis from a series of frequency components. The separated component is output as the deterministic frequency component 32 and is supplied to the synthesis unit 46. The synthesizing unit 46 synthesizes deterministic waveform data based on the deterministic frequency component 32. Reference numeral 48 denotes a subtraction unit that subtracts deterministic waveform data from the material waveform data 30. The result of this subtraction is output as noise component waveform data 34.

Referring back to FIG. 3, reference numeral 54 denotes attack & loop information, which is set by the user with reference to the material waveform data 30. Alternatively, it may be automatically set by using the result of the waveform analysis or the like in accordance with a user's designation. The contents of the attack & loop information 54 include the length of an attack portion that is read only once at the beginning of waveform reproduction, the length of a loop portion that is repeatedly read thereafter, and the like. Reference numeral 36 denotes a waveform synthesizing unit that synthesizes the waveform data of the attack unit and the loop unit based on the deterministic frequency component 32, the noise component waveform data 34, and the attack & loop information 54. The synthesized waveform data is usually stored as musical tone waveform data 38 on a hard disk or the like of a personal computer.

Here, an outline of the synthesizing process in the waveform synthesizing section 36 will be described. First, attack & loop information 5
4, the attack start address indicating the head of the attack part, the loop start address indicating the head and the end of the loop part, and the loop end address are determined. Next, among the deterministic frequency components of the loop section, a component having a value close to the phase of the loop start at the loop end is selected, and the phase at the loop end of the selected component is matched with the phase at the loop start. Is corrected to When the loop is a long loop (loop size of several hundred milliseconds or more), a component (nonharmonic component) having a value that is not close to the phase of the loop start at the loop end may be selected and corrected. Next, sine wave synthesis is performed based on the corrected frequency component, and waveform data of the loop section is generated.

Next, among the deterministic frequency components of the attack portion, components not used in the loop portion are processed so as to gradually fade out from the middle of the attack portion to the end of the attack portion, and the processed decision is made. Sine wave synthesis is performed based on the theoretical frequency components, and waveform data of the attack portion is generated. Furthermore, noise component waveform data 3
This is mixed with the attack portion and the loop portion while controlling the volume of No. 4. The waveform data of the attack portion and the loop portion created as described above is a waveform very similar to the material waveform data 30 and has a good connection from the attack portion to the loop portion and from the loop end to the loop start. Become data.

Reference numeral 60 denotes a pseudo bass synthesizer, which is a pseudo bass tone frequency data 51 indicating the highest frequency at which the pseudo bass should be reproduced in the portable telephone, a deterministic frequency component 32, and attack and loop information. The pseudo low sound waveform data 52 is generated based on the data. The pseudo-bass start frequency data 51 may be a frequency preset according to the model of the mobile phone (or the model of the headphone, the earphone, or the like), or a frequency that can be arbitrarily set by the user. . Here, an example of a method of determining the pseudo bass start frequency data 51 will be described with reference to FIG. In the figure, the horizontal axis is frequency or note number NN
The cutoff frequency (minimum frequency) is determined on the diagram according to the characteristics of the electroacoustic transducer of the mobile phone.

As described above, when it is determined whether or not to generate a pseudo bass sound at the cutoff frequency, there occurs a problem that the sound quality is significantly different before and after the cutoff frequency. Therefore, in the present embodiment, the pseudo bass is generated even at a frequency higher than the cutoff frequency, and the level of the pseudo bass is gradually increased as the frequency becomes lower, thereby alleviating the sense of discomfort. Specifically, a volume coefficient RVOL that increases as the frequency decreases in the range of "0 to 1" is determined as shown in the figure, and the volume coefficient RVOL is multiplied by the pseudo low sound waveform to realize such processing. The frequency at which the characteristic of the volume coefficient RVOL intersects the horizontal axis is called a "pseudo bass start frequency".

Returning to FIG. 3, an extraction unit 67 in the pseudo bass synthesizer 60 extracts a frequency component equal to or lower than the pseudo bass start frequency from the deterministic frequency components 32. Reference numeral 62 denotes a harmonic generation unit that generates a plurality of harmonic components exceeding the pseudo bass start frequency for each of the extracted frequency components. Here, the frequency of the extracted frequency component fluctuates with time, and accordingly, the frequency of the generated harmonic component fluctuates accordingly.

For example, the cut-off frequency (120 Hz)
It is assumed that 240 Hz, which is one octave higher than that, is set as the pseudo bass start frequency. In this case, at least double and triple harmonic components are generated for the frequency components of 120 <f ≦ 240 Hz in the deterministic frequency component 32. Similarly, for the frequency component of 80 <f ≦ 120 Hz, at least the triple and quadruple harmonic components are 6
At least 4 for frequency components 0 <f ≦ 80 Hz
Double and quintuple harmonic components will be generated.

Next, reference numeral 68 denotes an envelope converter.
The envelope of each harmonic component is output so that the sense of loudness (loudness) of the pseudo bass generated by each harmonic component matches the sense of volume of the original frequency component. The contents will be described with reference to FIG. According to the equal loudness curves previously shown in FIGS. 5 (a) and 5 (b), the bass range (for example, 100H
It can be seen that in order to generate the same volume sensation in the harmonic components (for example, 200 Hz and 300 Hz) as in z), the level of the harmonic components must be reduced and the range of the level change must be increased.

Therefore, in the envelope conversion section 68, if the envelope level of the extracted original frequency component is the one shown in the characteristic A of FIG. 7, this is converted into the characteristic B of the same figure. And outputs it as the envelope level of the harmonic component. In the low sound range of the equal loudness curves in FIGS. 5A and 5B, the sound pressure level of the equal loudness decreases by 10 to 15 dB every time the frequency doubles. Therefore, the level L1 in FIG. 7 is set to “10 to 15 dB × multiplier”. Also, the magnitude of the change in sound pressure level at which the change in loudness becomes equal is about 1.4 times in “Fletcher & Manson” and 1 time in “Robinson & Dadson” every time the frequency is doubled. Approximately 1 time. Therefore, the level ratio L3 / L2 in the figure
Is set to about “1.1 to 1.4 × multiplier”.

Referring back to FIG. 3, reference numeral 64 denotes an amplitude controller, which controls each harmonic component output from the harmonic generator 62.
The envelope level output from the envelope conversion unit 68 is multiplied. Reference numeral 66 denotes a multiple waveform mixing unit that mixes each of the enveloped harmonic components. The result of this mixing is stored in the hard disk of the personal computer as pseudo low sound waveform data 52. The normal musical sound waveform data 38 and the corresponding pseudo low sound waveform data 52 created as described above, when a user connects a mobile phone to a personal computer and performs a predetermined operation, as user-defined tone waveform data, The data is transferred to the waveform memory in the sound source 10.

Generally, in a waveform memory sound source, different normal musical tone waveform data 38 is stored for each tone range of each tone color (waveform data may be shared between tone colors and tone ranges). In the present embodiment, among the normal musical sound waveform data, the fundamental wave component of the deterministic frequency component included in the normal musical sound waveform data is used only for the normal musical sound waveform data used for generating a musical tone at a pitch equal to or lower than the pseudo low sound start frequency. The waveform data 52 is stored in the waveform memory. Basically, it may be stored in a one-to-one correspondence with the normal musical sound waveform data 38, but this is not always necessary. In some cases, a plurality of pseudo low sound waveform data may be stored for one normal musical sound waveform data, or one pseudo low sound waveform data may be stored corresponding to a plurality of normal musical sound waveform data. Good. The normal musical sound waveform data 38 stored in the waveform memory is read at a speed based on the F number when a musical sound signal is formed, so that a desired pitch is realized. Then, in the present embodiment, the frequency component of the normal musical sound waveform data 38 that cannot be reproduced due to the capability of the sound system 12 changes according to the F number. Therefore, in the present embodiment, a plurality of types of pseudo low sound waveform data 52 are generated for each sound range.

For this reason, in the present embodiment, the range to which the one pseudo bass waveform data 52 is applied is:
It is narrower than the range to which one normal musical sound waveform data 38 is applied, and the number of pseudo low sound waveform data 52 tends to increase. However, the memory area occupied by the pseudo low sound waveform data 52 can be made extremely small as compared with the normal musical sound waveform data 38 by suppressing the sampling frequency. The reason will be described.

First, the sampling frequency of the musical tone waveform is about 32 to 48 kHz in general consumer equipment, because the upper limit of the reproduction frequency is set to about 15 to 20 kHz. On the other hand, in the pseudo low sound waveform data 52, although the upper limit of the reproduction frequency is about 2 kHz (although it varies depending on the cutoff frequency), it is sufficient to secure the sampling frequency of about 5 to 10 kHz. For this reason, the data amount of one pseudo low sound waveform data 52 can be suppressed to about one-several to several tenths of one normal musical sound waveform data 38. When such a low sampling frequency is applied, it is preferable to employ high-precision interpolation between sample points such as "8-point interpolation".

1.3.2. Waveform synthesis processing Performance information (for example, an SMF (Standard MIDI Format) file) for reproducing a ringtone is stored in the ROM 22 and the RAM 24 in the mobile phone. When there is an incoming call to the mobile phone, the performance information is reproduced, and the CPU 20 sends the MID to the sound source 10.
I-events are sequentially input, and a tone waveform is synthesized in the sound source 10 based on this. The content of the sound source control process will be described with reference to FIG.

(1) When the pseudo bass effect is off First, when a note-on event occurs, a note-on event processing routine shown in FIG. In the figure, when the process proceeds to step SP2, the part number is substituted for the variable PT, the note number is substituted for the variable NN, and the velocity is substituted for the variable VEL. Next, when the process proceeds to step SP4, it is determined whether or not the flag PLE is "1". Note that the flag PLE is a flag indicating the on / off state of the pseudo bass effect, and “1” indicates on and “0” indicates off. The value of the flag PLE can be switched at any time by performing a predetermined operation by the user.

If the flag PLE is "0", "N"
O "is determined, and the process proceeds to step SP10. Here, the normal sound generation control subroutine shown in FIG. 2B is called. In the figure, when the process proceeds to step SP22, the sound source 10 is assigned one sounding channel. The channel number of this assigned sounding channel is a1.

Next, when the process proceeds to step SP24,
For the channel number a1 in the sound source, the part number PT
Are set according to the tone color TC (PT), the note number NN, and the velocity VEL. Here, the tone parameters include the following.

(1) Tone TC (P
Of the plurality of normal tone waveform data 38 corresponding to T), the normal tone waveform data 38 corresponding to the note number NN
Address Information of (Selected Waveform Data) Normally, the musical tone waveform data 38 is composed of an attack portion and a loop portion, and therefore, it is necessary to set the start and end addresses thereof. However, the tone TC
Depending on the (PT), the normal tone waveform data 38 may be composed of only a loop portion or may be composed of only one-shot waveform data. Velocity V
In some cases, different waveform data is applied to each EL range.

(2) F number corresponding to note number NN In the normal musical tone waveform data 38, an original pitch OP is determined for each waveform data. When the note number NN is designated, the normal tone waveform data 3 is set according to the difference between the original pitch OP of the selected waveform data and the note number NN and the sampling frequency of the waveform data.
8, the F-number is determined.

(3) Volume Envelope Parameter When the timbre TC (PT), the velocity VEL, and the note number NN are specified, the volume envelope parameter for specifying the volume envelope is determined in accordance with them. (4) Other parameters In addition, tone color TC (PT), note number NN, tone color filter parameter corresponding to velocity VEL, pitch modulation parameter, amplitude modulation parameter and the like are appropriately set.

Next, when the process proceeds to step SP26,
Start of sound generation is instructed for channel number a1 of the sound source. Thus, the processing for the note-on event is completed. Thereafter, the sound source 10 reads out the normal tone waveform data 38 at a speed corresponding to the note number NN, further performs a filtering process according to the timbre filter parameter, and a time change process of a volume according to the volume envelope parameter. Is performed, and tone signals related to the channel number a1 are sequentially generated without including the pseudo bass.
This tone signal is generated via the sound system 12. Even if the tone signal contains a frequency component lower than the cutoff frequency, the component is not reproduced by the sound system 12 and the user cannot hear it.

(2) When the pseudo bass effect is on When the note on event occurs when the pseudo bass effect is on (flag PLE = 1), the above steps SP2 and S
The process proceeds to step SP6 via P4. here,
Based on the timbre TC (PT) and the note number NN, it is determined whether or not a pseudo bass sound should be generated, that is, whether or not a frequency component equal to or lower than the pseudo bass start frequency is included. Even if the note number NN is specified, the fundamental frequency may be shifted in octave units depending on the timbre. Therefore, the determination is made in consideration of the timbre TC (PT).

For example, if the cutoff frequency is 120 Hz,
Let us assume a case where the pseudo bass start frequency is 240 Hz and the note number directly corresponds to the fundamental frequency (no octave shift). If the reference pitch is A4 = 440 Hz, A3 = 220 Hz and A # 3 =
Since 233.08 Hz and B3 = 246.92 Hz,
It can be seen that a pseudo low sound waveform should be generated when the pitch is A # 3 or less.

Next, when the processing proceeds to step SP8, the processing branches according to the result of the determination in step SP6. First, when it is determined that "a pseudo low sound waveform should not be generated (note number is B3 or more)", the process proceeds to step SP1.
Go to 0. Thus, the normal sound generation control subroutine (FIG. 2B) is called in the same manner as when the pseudo bass effect is off. Accordingly, one tone generation channel is assigned to the note-on event, and a tone signal based on the normal tone waveform data 38 is sequentially generated in the tone generation channel.

On the other hand, "YES" in step SP8.
Is determined, the process proceeds to step SP12. Here, the pseudo bass sound generation control routine shown in FIG. 8 is called. In the figure, when the processing proceeds to step SP32, the sound source 10 is assigned two sounding channels. Let the channel numbers of the assigned sounding channels be a1 and a2. Next, when the process proceeds to step SP33, the note number NN and the timbre TC (P
T) and the volume coefficient characteristic based on the volume coefficient characteristic (FIG. 14).
RVOL is determined.

Next, when the process proceeds to step SP34,
For the channel number a1 in the sound source, the part number PT
Are set according to the tone color TC (PT), the note number NN, and the velocity VEL. The contents of the processing are the same as in step SP24 described above. Next, when the process proceeds to step SP36, a parameter for a pseudo bass is set in the channel number a2 corresponding to the tone signal generated in the channel number a1.

Here, there are the following tone parameters set for the pseudo bass. (1) Address information of pseudo low sound waveform data 52 (selected pseudo low sound waveform data) corresponding to the normal musical sound waveform data 38 selected in step SP34. (2) Pseudo low sound waveform data 52 corresponding to note number NN
F number. The F number for the pseudo low sound waveform data 52 is also determined in the same procedure as the F number of the normal musical sound waveform data 38.
That is, the original pitch OP of the pseudo low sound waveform data
And the note number and the sampling frequency of the pseudo low sound waveform data,
The number is determined. Here, the original pitch OP of the pseudo low sound waveform data has the same value as the original pitch OP of the corresponding normal musical sound waveform data (waveform data reproduced by the channel number a1). Therefore, the F number of the pseudo low sound waveform data normally has a predetermined proportional relationship with the F number of the musical sound waveform data (however, the sampling frequencies are different from each other). As a result, in the channel number a2, a pseudo bass sound in which the pitch and the time axis are completely synchronized with the tone signal generated by the channel number a1 is obtained.

(3) Volume Envelope of Pseudo Bass Corresponding to Volume Envelope of Channel Number a1 As described in FIG. 7, the volume envelope of the pseudo bass (characteristic B) is the same as the volume envelope of the original waveform (characteristic A). Is different. Therefore, the volume envelope for the pseudo bass is set by deforming the volume envelope of channel number a1. However, both the normal musical sound waveform data 38 and the pseudo low sound waveform data 52 store waveform data in which the volume envelope changes in the attack portion of the attack portion and the loop portion. Therefore, in each channel of the waveform memory sound source, it is not necessary to give a time-dependent change in the volume for the attack portion, and a volume envelope parameter for specifying a flat volume envelope of the attack portion is set. FIG. 9 shows a volume envelope (characteristic A ') for the normal musical sound waveform data 38 assigned by the channel number a1 and a volume envelope (characteristic B') for the pseudo low acoustic waveform data 52 assigned by the channel number a2. Here is an example.

Each of the volume envelopes follows the relationship of equal loudness described with reference to FIG. 7, and starts changing when the waveform data reproduced in each channel enters the loop portion from the attack portion. In the flat portion, the loudness of the frequency component equal to or lower than the pseudo low sound onset frequency included in the reproduced normal musical sound waveform data 38 substantially matches the loudness of the pseudo low sound waveform data, so that the characteristic B ′ is more than the characteristic A ′. The level is set to be low. Further, in the loop portion, the loudness change amount of the component lower than the pseudo-bass start frequency included in the loop portion of the reproduced normal tone waveform data and the loudness change amount of the loop portion of the pseudo-low-tone waveform data are substantially the same. The slope of B 'is set to be steeper than the slope of characteristic A'. As a result, in the channel number a2, a pseudo low sound waveform in which the loudness characteristic follows a component lower than the pseudo low tone start frequency included in the tone signal generated by the channel number a1 is obtained.

Further, the volume envelope of the channel number a2 thus obtained is multiplied by a volume coefficient RVOL. As a result, a change in sound quality with respect to the note number NN can be moderated around the lowest frequency, and a natural tone signal can be generated. (4) Other parameters The contents of other various parameters are basically set similarly to the channel number a1.

Returning to FIG. 8, when the process proceeds to step SP38, a sound generation start is instructed for the channel numbers a1 and a2 in the sound source. Thus, the processing for the note-on event is completed. Thereafter, for the channel number a1 of the sound source 10, the normal musical sound waveform data 38 is read at a speed corresponding to the note number NN, and the musical tone signal relating to the channel number a1 is sequentially generated without including the pseudo bass. In synchronization with this, in channel number a2,
The pseudo bass waveform data 52 corresponding to the note number NN is read, and pseudo bass signals are sequentially generated. Thereby, both signals are emitted via the sound system 12. Although the sound system 12 does not reproduce a component having a frequency lower than the lowest frequency of the tone signal, the user can listen to a pseudo bass corresponding to the component instead of the non-reproduced component, and determine whether the component is reproduced. Illusion.

As described above, according to the present embodiment, the volume envelope for the normal tone waveform and the volume envelope for the pseudo low tone waveform can be individually controlled, so that the volume is controlled according to the equal loudness curve according to the situation at each time. It is possible to control the level and the dynamic range.

2. Second Embodiment Next, a second embodiment of the present invention will be described. Although the hardware configuration of the second embodiment is the same as that of the first embodiment, the waveform data prepared in the waveform memory and the software configuration for control are slightly different from those of the first embodiment. explain.

(1) Waveform Data Creation Processing In this embodiment, the same waveform data creation processing as that described with reference to FIGS. 3 and 4 is executed, and the normal musical tone waveform data 38 and the pseudo low tone waveform data 52 are obtained. . Further, in the present embodiment, the processing shown in FIG. 10 is executed.

In the figure, reference numeral 75 denotes a volume coefficient calculating unit.
When a note number NN is given, a volume coefficient characteristic (FIG. 1)
A volume coefficient RVOL is calculated based on 4). Reference numerals 72 and 74 denote amplitude control units for controlling the amplitudes of the waveform data 38 and 52. Further, the amplitude control section 72 multiplies the obtained amplitude by a volume coefficient RVOL. That is, the first
A level difference corresponding to the difference between the attack portions of the characteristics A ′ and B ′ in FIG. 9 of the embodiment is added to the envelopes of the two waveform data, and thereafter, the amplitude control unit 72 is further multiplied by the volume coefficient RVOL to obtain the two waveform data. Is set. Reference numeral 76 denotes a mixing unit, which mixes the amplitude-controlled both waveform data and outputs the result as pseudo low-pitched waveform data 78. These waveform data 38 and 78 are stored in the hard disk of the personal computer, and the waveform data 52 is deleted. In this manner, the normal musical sound waveform data 38 and the pseudo low sound waveform data 52 corresponding to the frequency components equal to or lower than the pseudo low sound start frequency included therein, and the pseudo low sound waveform amplitude controlled to have the same loudness as the frequency components. The data were mixed with each other to prepare pseudo bass sound waveform data 78.

Here, of the contents described with reference to FIG. 7, the sound pressure level is attenuated to make the loudness of the pseudo bass sound uniform, but the magnitude of the change in the sound pressure level is made to make the loudness change uniform. Has not gone. This is because "Robinson &Dadson" has determined that the ratio of the magnitude of the change in the sound pressure level is close to 1, and that it may be omitted. Created normal musical sound waveform data 3
8 and the corresponding pseudo bass sound waveform data 78
The data is transferred from the personal computer to the waveform memory in the sound source 10 of the mobile phone according to a predetermined operation of the user. The waveform memory stores the normal tone waveform data 38 for each tone range of each tone color, and the pseudo low tone included waveform data is used for tone generation at a pitch whose fundamental component is equal to or lower than the pseudo low tone start frequency. Normal tone waveform data 38
May be prepared and stored in the waveform memory.

(2) Note-On Event Processing In this embodiment, when a note-on event occurs, a note-on event processing routine shown in FIG. 2A is started, as in the first embodiment. The process of step SP10 executed when the pseudo bass effect is off, or when the pseudo bass effect is on and there is no frequency component equal to or lower than the pseudo bass start frequency in the generated tone signal is the same as that of the first embodiment. Exactly the same. If the pseudo bass effect is on and the generated tone signal contains a frequency component equal to or lower than the pseudo bass start frequency, in step S12, instead of the processing in FIG. Be called.

Step SP4 executed in this routine
Steps SP2, SP44, and SP46 are the same as the contents of steps SP22, SP24, and SP26 (FIG. 2 (b)), which are respectively performed on the normal tone waveform. However, step SP44
, The address information, the F number, the volume envelope parameter, and other parameters for the pseudo bass sound waveform data 78 are set in the sound source 10 in place of the normal tone waveform data 38. The address information to be set is
Note number NN of a plurality of normal tone waveform data 38 corresponding to tone color TC (PT) stored in the waveform memory
Are the address information of the pseudo bass sound waveform data 78 corresponding to the normal musical sound waveform data 38 corresponding to. F number,
The volume envelope parameter and other parameters may be basically set to the same values as the corresponding parameters of the normal tone waveform data 38.

Thus, in step SP46,
When the start of sound generation is instructed for the channel number a1 of the sound source, the sound source 10 reads the pseudo low-pitched waveform data 78 at a speed corresponding to the note number NN, and further according to the tone color filter parameter. Filter processing and time change processing of the sound volume according to the sound volume envelope parameter are performed, and the tone signal related to the channel number a1 is sequentially generated in a state including the pseudo bass sound. This tone signal is generated via the sound system 12. Since this tone signal includes a pseudo low tone corresponding to a frequency component below the lowest frequency that cannot be reproduced, the user can hear as if the frequency component is being reproduced. Furthermore, for a frequency component equal to or higher than the lowest frequency and equal to or lower than the pseudo bass start frequency, a pseudo bass sound waveform is generated in accordance with the volume coefficient characteristic (FIG. 14) so that the volume coefficient RVOL increases as the frequency decreases. In the vicinity of the lowest frequency, a change in sound quality with respect to the note number NN can be moderated.

According to this embodiment, even when a pseudo bass is generated, the number of sound channels assigned to one note-on event can be suppressed to one channel. Therefore, it is particularly suitable for use when it is desired to suppress an increase in the number of sounding channels.

3. Third Embodiment Next, a third embodiment of the present invention will be described. The hardware configuration of the third embodiment is the same as that of the first embodiment except that the sound source 10 is not a waveform memory sound source but a frequency modulated sound source (FM sound source). Although the software configuration is slightly different from that of the first embodiment, only the differences will be described below.

(1) Waveform Data Creation Processing In this embodiment, since the tone signal is generated by the FM tone generator method, the waveform data creation processing as in the first and second embodiments is not executed.

(2) Normal tone generation control in note-on event processing In this embodiment, when a note-on event occurs, a note-on event processing routine shown in FIG. 2A is started as in the first embodiment. You. However, in the present embodiment, when the pseudo bass should not be generated, the normal sound generation control subroutine shown in FIG. 12A is called in step SP10.

In FIG. 12A, the processing is step SP5.
When proceeding to 2, the sound source 10 is assigned one sounding channel. The channel number of this assigned sounding channel is a1.

Next, when the processing proceeds to step SP54,
For the channel number a1 in the sound source, the part number PT
Are set according to the tone color TC (PT), the note number NN, and the velocity VEL. Generally, the tone parameters of the FM tone generator set for the tone generator channel are based on the tone data prepared for each tone color TC, and the note number NN and the basic tone parameter for the tone signal are used. It is prepared by adding a correction (scaling) according to the velocity VEL. Here, the tone parameters include the following.

(1) Algorithm In the FM tone generator system adopted in this embodiment, an algorithm (connection state of n operators) is selected according to the tone color TC (PT). Further, the type of waveform data used by each operator (sine wave, half-wave rectified sine wave, full-wave sine wave rectified waveform, etc.), and the progress speed of phase data for generating the waveform data are controlled. Pitch data (controls the pitch of waveform data), a multiplier for the pitch data for each operator (the progress speed of the phase data in each operator is controlled by the product of the multiplier and the pitch data), and low-frequency modulation control data (vibrato And the like, and the envelope parameters for controlling the envelope waveform applied to the waveform data generated by each operator include the tone color TC (PT) and the note number N.
N, which is determined according to the velocity VEL. As the contents of the algorithm, various kinds of contents can be considered as the contents of the algorithm. As a simple example, a case in which "n = 2" operators OP1 and OP2 are connected in series as shown in FIG. Can be

(2) Volume Envelope Parameter The volume envelope of the tone signal output from the FM sound source corresponds to the envelope assigned to the operator at the final stage of the above algorithm (OP2 in the example shown). As described above, the envelope parameters of the envelope are determined according to the tone color TC (PT), the note number NN, and the velocity VEL.

(3) Other Parameters When filtering the output of the algorithm, the timbre TC (PT), the note number NN,
A tone color filter parameter or the like corresponding to the velocity VEL is set. Further, a pitch envelope parameter for controlling a pitch envelope for changing the pitch of the generated tone signal may be set.

Next, when the processing proceeds to step SP56,
Start of sound generation is instructed for channel number a1 of the sound source. Thus, the processing for the note-on event is completed. Thereafter, the tone generator 10 sequentially generates the tone signal related to the channel number a1 without including the pseudo bass. This tone signal is generated via the sound system 12. Even if the tone signal contains a frequency component lower than the lowest frequency, the component is not reproduced by the sound system 12, and the user cannot hear it.

(3) Pseudo Bass Sound Generation Control in Note-On Event Processing In the note-on event processing routine (FIG. 2 (a)), when the processing proceeds to step SP12, a pseudo bass sound generation control routine shown in FIG. 12 (b) Is called. When the process proceeds to step SP62 in the figure,
The sound source 10 is assigned two sounding channels. Let the channel numbers of the assigned sounding channels be a1 and a2. Next, the process proceeds to step S
Proceeding to P63, the note number NN and the tone color TC (PT)
And the volume coefficient RVOL based on the volume coefficient characteristic (FIG. 14).
Is determined.

Next, when the processing proceeds to step SP64,
For the channel number a1 in the sound source, the part number PT
Are set according to the tone color TC (PT), the note number NN, and the velocity VEL. The processing content is the same as that in step SP5 described above.
Same as 4. Next, when the process proceeds to step SP66, m operators for pseudo bass are reserved in the channel number a2 corresponding to the tone signal generated in the channel number a1, and these parameters are set.

Here, there are the following musical tone parameters set for the pseudo bass. (1) Algorithm In order to generate a pseudo bass, the channel number 2 contains OP
An algorithm (see FIG. 13B) having a configuration in which two operators 3 and OP4 are connected in parallel is set. The frequency components of the tone signal generated in channel number a1 include:
A frequency component equal to or lower than the pseudo bass start frequency is included.
Here, the operator at the last stage of the channel number a1
It is assumed that an operator whose multiplier of the pitch data is 1 is generating the lowest tone of the channel. In this case, the pitch data of the frequency f corresponding to the note number NN is set in the channel number a2 as in the channel number a1,
Further, each operator of the channel number a2 appropriately sets a multiplier to generate a harmonic of the frequency f. In each operator, a combination of a plurality of multipliers (for example, “2, 3”, “3, 4”) in which the pitch of the generated waveform data is greater than the pseudo bass start frequency and the greatest common divisor is “1” ,...) Are set, and the pitch frequencies of the actually generated signals are “2f, 3f” and “3f”.
f, 4f ",....

(2) Volume Envelope Parameter When the timbre TC (PT), the velocity VEL, and the note number NN are designated, the volume envelope assigned to the pseudo bass operator (OP3, OP4 in the illustrated example) is designated. For this purpose, a volume envelope parameter is determined. The relationship between the volume envelopes for both channel numbers a1 and a2 is the same as in the first and second embodiments.
That is, a volume envelope which is included in the tone signal generated in the channel a1 and has an equal loudness relationship with a volume envelope of a low-frequency component equal to or lower than the pseudo bass start frequency is obtained, and these are each multiplied by a volume coefficient RVOL. Envelope parameters are set for the two operators of channel number a2, respectively. Here, the envelope parameters set for each operator are different from each other according to the pitch of the generated waveform data.

(3) Other parameters Other parameters such as note number NN and tone color filter parameters corresponding to velocity VEL are set. When the pitch envelope is set to the channel number a1, the same pitch envelope is set to the channel number a2, so that the pitch of the pseudo bass generated by the channel number a2 is generated by the channel number a1. It is possible to follow the pitch fluctuation of the tone signal. Here, the tone parameters for the pseudo bass sound described above can be created in the same manner as the tone parameters for the tone signal. Specifically, first, each tone T
The data for the pseudo bass is included in the tone color data prepared for each C. Then, a correction (scaling) according to the note number NN and the velocity VEL is added to the basic tone parameter for the pseudo bass included in the tone color data, thereby creating a tone parameter for the pseudo bass.

Returning to FIG. 12 (b), the processing proceeds to step SP5.
At step 8, the sound generation start is instructed for the channel numbers a1 and a2 in the sound source. Thus, the processing for the note-on event is completed. Thereafter, in the channel number a1 of the sound source 10, a tone signal is sequentially generated without including a pseudo bass. In synchronization with this, a pseudo bass signal corresponding to the note number NN is sequentially generated for the channel number a2. Both signals are sound system 1
When the tone is generated via the channel No. 2, the user can hear the frequency component as if the frequency component below the lowest frequency is not reproduced in the tone signal of the channel number a 1 due to the pseudo bass sound of the channel number a 2. Illusion as if you were. Further, for the frequency components equal to or higher than the lowest frequency and equal to or lower than the pseudo bass start frequency, the lower the frequency, the higher the volume coefficient RV according to the volume coefficient characteristic (FIG. 14).
Since the pseudo low sound waveform is generated so that the OL becomes higher, the change in the sound quality with respect to the note number NN around the lowest frequency can be moderated.

4. Fourth Embodiment Next, a fourth embodiment of the present invention will be described. Although the hardware configuration of the fourth embodiment is the same as that of the third embodiment, the software configuration is slightly different from that of the third embodiment, so only the differences will be described.

(1) Sound Control with Pseudo Bass in Note-On Event Processing In this embodiment, when the processing proceeds to step SP12 in the note-on event processing routine (FIG. 2 (a)), it is shown in FIG. 12 (c). The sound control routine with pseudo bass is called. In the figure, when the processing proceeds to step SP72, the sound source 10 is assigned one sounding channel. The channel number of this assigned sounding channel is a1. Next, when the process proceeds to step SP73, the note number NN and the timbre TC (P
T) and the volume coefficient characteristic based on the volume coefficient characteristic (FIG. 14).
RVOL is determined.

Next, when the process proceeds to step SP74,
An operator (m + n) is secured for the channel number a1 in the sound source. Here, in this embodiment, it is assumed that an FM sound source capable of changing the number of operators for each channel is used. “M” and “n” are the numbers of operators for normal sounding and pseudo bass in the third embodiment. Next, the tone color TC (PT) corresponding to the part number PT, the note number NN, and the velocity V
A tone parameter corresponding to EL is set.

The algorithm set here is equal to the algorithm of the third embodiment in which the algorithm for normal sound generation and the algorithm for pseudo bass are connected in parallel. One example is shown in FIG. Other settings of the tone parameters are the same as those in the third embodiment.

Next, when the processing proceeds to step SP76,
The start of sound generation is instructed for the channel number a1 in the sound source. Thus, the processing for the note-on event is completed. Thereafter, in the channel number a1 of the sound source 10, tone signals including pseudo bass sounds are sequentially generated.

As described above, the difference between the third and fourth embodiments resides in that two or one sounding channels are secured when performing sound control with pseudo bass. Which embodiment to select may be determined based on whether the maximum number of operators per channel is “n + m” or more. In the example of FIG. 13, if the maximum number of operators is "3", the configuration of the third embodiment ((a) + (b) of FIG. 13) must be adopted. If the maximum number of operators is “4” or more, any of the embodiments can be adopted. However, the fourth embodiment is more advantageous in that the number of channels can be suppressed.

5. Fifth Embodiment Next, a fifth embodiment of the present invention will be described. The hardware configuration of the fifth embodiment is the same as that of the first embodiment except for the sound source 10. However, when a note-on event occurs, steps SP2 and SP10 in FIG. 2A (steps SP22 through SP22 in FIG.
The same processing as in P26) is performed. That is, in the present embodiment, the processing of software is not changed based on whether or not to generate a pseudo bass.

Here, the configuration of the sound source 10 in the present embodiment will be described with reference to FIG. In FIG. 7A, reference numeral 82 denotes a normal tone signal generator, which includes a note number NN and a tone color TC.
Based on (PT) and velocity VEL, a normal tone signal not including pseudo bass is generated. The normal tone signal generator 82 may generate a tone signal by any method such as a waveform memory sound source and an FM sound source. Reference numeral 84 denotes a pseudo bass sound generator that generates a pseudo bass signal in real time with respect to the normal tone signal sequentially output from the normal tone signal generator 82.

Here, the detailed structure of the pseudo bass generating section 84 will be described with reference to FIG. In the figure, reference numeral 92 denotes an LPF, which extracts a component equal to or lower than the pseudo bass start frequency from a normal tone signal. Reference numeral 93 denotes a fundamental wave extraction unit, which extracts a fundamental wave component from the output signal of the LPF 92. A harmonic generation unit 94 generates a harmonic of the fundamental wave component. For example, when the frequency of the fundamental wave component is f, the harmonic generation unit 94 extracts the harmonic components of 2f, 3f, 4f,. Reference numeral 96 denotes an equal loudness generating unit that adjusts the amplitude of each harmonic component according to the equal loudness curve so as to exhibit the same volume feeling as that of the fundamental wave component. Reference numeral 98 denotes an adder, which adds each harmonic component whose amplitude has been adjusted.

Returning to FIG. 8A, reference numeral 86 denotes a coefficient generator, which is a note number NN and a tone color T supplied to the sound source 10.
Based on C (PT) and the volume coefficient characteristic (FIG. 14),
Outputs volume coefficient RVOL. Reference numeral 85 denotes a multiplying unit which adds a volume coefficient RV to the pseudo bass signal output from the pseudo bass generating unit 84.
Multiply OL. A mixer 88 mixes a normal tone signal and a pseudo bass signal and outputs the mixed signal to the sound system 12.

According to the present embodiment, since the pseudo bass signal is generated based on the normal tone signal sequentially generated by the normal tone signal generating section 82, the sound channel and the tone generation slot are sacrificed for the pseudo bass generation. , A pseudo bass can be generated. Furthermore, for a frequency component equal to or higher than the lowest frequency and equal to or lower than the pseudo bass start frequency, a pseudo bass sound waveform is generated in accordance with the volume coefficient characteristic (FIG. 14) so that the volume coefficient RVOL increases as the frequency decreases. , Note number N around the lowest frequency
The change in sound quality with respect to N can be moderated.

6. Modifications The present invention is not limited to the embodiments described above,
For example, various modifications are possible as follows. (1) In each of the above embodiments, the present invention is implemented on a mobile phone, but the same function may be used for various electronic musical instruments, amusement devices, personal computers, and other devices that generate musical sounds. . Further, the software used for these can be stored in a recording medium such as a CD-ROM or a floppy (registered trademark) disk and distributed, or can be distributed through a transmission path.

(2) In the fifth embodiment, the coefficient generating section 86 calculates the volume coefficient RVOL based on the note number NN and the tone color TC (PT). The frequency of the fundamental wave component may be used. According to this configuration, since the volume coefficient RVOL can be determined without using a tone parameter specific to a sound source, an audio signal output from a source other than the sound source (eg, a record, a CD, a wired / wireless broadcast, a magnetic tape, etc.) for,
Appropriate pseudo bass can be given, and it can be applied to a wide range.

(3) In the above embodiments, the frequency (240 Hz) one octave higher than the lowest frequency (120 Hz) is set as the pseudo bass start frequency. However, the method of selecting the pseudo bass start frequency is not limited to this, and may be set to, for example, a frequency that is オ ク タ octave higher than the lowest frequency, or a frequency that is １ ／ octave higher.

(4) In the above embodiment, a high-pass filter is inserted between the sound source 10 and the sound system 12 so as to attenuate a frequency component lower than the lowest frequency reproducible by the sound system, and a frequency lower than the lowest reproducible frequency is used. May be cut off. Thereby, the power consumption of the amplifier in the sound system 12 can be reduced.

(5) PC in which the sound source 10 has a waveform RAM
In the case of an M sound source, a pseudo low sound waveform may be generated by analyzing existing waveform data. At this time, the user may select or specify a pseudo bass start frequency, and automatically create pseudo bass waveform data based on the selected or specified pseudo bass start frequency.

(6) When the present invention is applied to an electronic musical instrument, when incorporating the present invention into an electronic musical instrument equipped with a sound system, it is preferable that a quasi-bass effect matching the sound system be set in advance by the manufacturer. . Even in such a case, a plurality of settings may be prepared on the maker side so that the user can select a desired setting from the settings. on the other hand,
In the case of an electronic musical instrument (e.g., a synthesizer) without a sound system or a sound source on a sound board for a personal computer, it is impossible to specify the sound system in advance. In this case, the setting of the pseudo low tone starting frequency, the lowest frequency, the amount of attenuation, the amount of amplitude compression, and the like of the pseudo low tone effect may be performed by a panel of an electronic musical instrument or a personal computer equipped with a sound board.

(7) In the above embodiment, as parameters for generating a pseudo bass, a pseudo bass start frequency, an attenuation amount (level L1 in FIG. 7), and an amplitude compression amount of the pseudo bass (FIG. Level ratio L3 / L2) was used. However, the amount of attenuation and the amount of amplitude compression may be fixed parameters, and the pseudo bass may be generated based only on the pseudo bass start frequency. Alternatively, the pseudo bass may be generated based only on the amount of attenuation and the pseudo bass start frequency without considering the change in the amplitude compression in the pseudo bass.

(8) In the above embodiment, when any one of a plurality of sound systems is used by switching, the pseudo bass start frequency for each sound system is stored in advance, and the sound system to be used is stored. The setting of the pseudo bass effect may be automatically performed in accordance with the switching state of.

(9) The control data (pseudo bass control data) for controlling the pseudo bass may be included in a part of the tone data of each tone. Further, the tone color data may include a plurality of pseudo bass control data corresponding to different lowest frequencies. In this case, if the lowest frequency of the sound system 12 is specified in advance by the user, the pseudo bass control data matching the lowest frequency can be automatically selected and used by simply selecting the tone. become.

(10) In the third and fourth embodiments using the FM sound source, an algorithm is used in which two operators are connected in parallel to generate a pseudo bass, but other algorithms may be used. . For example, when using an algorithm in which two operators are connected in series,
The pitch data having the same pitch as the frequency of the low-frequency component that is not reproduced is set. The operator on the modulator side generates waveform data with the same pitch as the frequency using the multiplier “1”, and the operator on the carrier side uses the multiplier “2” to generate the waveform data. What is necessary is just to generate the waveform data of a pitch twice the frequency. By applying frequency modulation to the double pitch waveform data with the same pitch waveform data, side band frequency components are generated at intervals of frequencies corresponding to the same pitch with the double pitch as the center. I do. A pseudo bass can be generated by using the carrier component of the double pitch and a sideband component one above (having a pitch three times the frequency of the low frequency component that is not reproduced).

In this case, the volume ratio between the carrier component and the immediately higher sideband component is determined by the output level of the operator on the modulator side. For ease of control, it is preferable that the envelope of the operator on the modulator side is not fluctuated with time, that is, the volume ratio is set to a fixed value. As for the envelope of the carrier-side operator, the envelope parameter may be set so as to change with time while maintaining the relationship between the volume of the low-frequency component that is not reproduced and the equal loudness.

(11) In the above embodiment, the pseudo bass sound is generated by the waveform memory sound source or the FM sound source, but the sound source types are not limited to these two. For example, in the case of a sound source of a harmonic synthesis method or a partial sound synthesis method, a pseudo bass can be generated using one or more of a plurality of oscillators of each channel. In the case of a ring modulation type sound source, harmonics generated by ring modulation of two series of oscillators can be used for pseudo bass. If the sound source is capable of performing non-linear conversion of waveform data, a pseudo bass can be generated based on harmonics generated by the non-linear conversion. In addition, the present invention may be applied to a physical model sound source or an analog modeling sound source.

(12) Although the pseudo bass effect can be turned on / off in the above embodiment, it may be turned on all the time.

[0094]

As described above, according to the present invention, it is possible to determine whether the designated pitch is equal to or less than a predetermined boundary pitch related to the electro-acoustic transducer by determining whether the designated pitch is equal to or less than the first or second boundary pitch. Since the second waveform signal is generated, it is possible to generate a pseudo bass while reducing the required amount of calculation.

[Brief description of the drawings]

FIG. 1 is a hardware block diagram of a mobile phone according to a first embodiment of the present invention.

FIG. 2 (a) Note-on event processing routine and
6B is a flowchart of a normal sound generation control subroutine.

FIG. 3 is a block diagram showing the contents of a waveform data creation process in the first embodiment.

FIG. 4 is a block diagram showing the contents of a waveform data analysis process in the first embodiment.

FIG. 5 is a diagram showing an equal loudness curve.

FIG. 6 is a diagram showing a component analysis result of a waveform.

FIG. 7 is an envelope conversion characteristic diagram in the first embodiment.

FIG. 8 is a flowchart of a sound generation control routine with pseudo bass in the first embodiment.

FIG. 9 is a diagram illustrating an example of a volume envelope in the first embodiment.

FIG. 10 is a block diagram illustrating a main part of a waveform data creation process according to a second embodiment.

FIG. 11 is a flowchart of a sound generation control routine with pseudo bass in the second embodiment.

FIG. 12 is a flowchart of a control routine in the third and fourth embodiments.

FIG. 13 is a block diagram of an algorithm according to the third and fourth embodiments.

FIG. 14 is a diagram illustrating a sound volume coefficient characteristic of each embodiment.

FIG. 15 is a block diagram of a sound source 10 according to a fifth embodiment.

[Explanation of symbols]

2 ... communication unit, 3 ... microphone, 4 ... coder /
Decoder, 6 Display, 8 Input device, 10 Sound source, 12 Sound system, 14 Bus, 16
... MIDI interface, 18 ... vibrator, 2
0: CPU, 22: ROM, 24: RAM, 30
…… material waveform data, 32 …… deterministic frequency components, 3
4 ... noise component waveform data, 36 ... waveform synthesis unit, 3
8: Normal tone waveform data, 40: Waveform analysis unit, 42
... FFT analysis processing unit, 44... Continuous component separation unit, 46
... Synthesis section, 48... Subtraction section, 51... Pseudo low tone start frequency data, 52... Pseudo low sound waveform data, 54...
... Harmonic generator 64, Amplitude controller 66, Multiple waveform mixer 67 Extractor 68 Envelope converter 72 74 74 Amplitude controller 75 Volume coefficient calculator .., 76... Mixing section, 78... Pseudo low tone waveform data, 82... Normal tone signal generating section, 84... Pseudo low tone generating section, 85.
Mixer, 92: LPF, 93: Fundamental wave extraction unit, 94
…… Harmonic generation part, 96 …… Loudness generation part, 98…
... Addition unit.

Claims (5)

[Claims] A second audio signal generating step of generating a second audio signal including a pseudo bass corresponding to the first audio signal; and a second audio signal having a high frequency in a predetermined range of the second audio signal. A coefficient generation step of generating a coefficient that becomes gradually smaller, a level control step of controlling a level of the second audio signal in accordance with the coefficient, and a step of synchronizing the second audio signal with the first audio signal. And an output step of outputting. 2. The sound signal generating step includes the steps of: assigning a sound channel to the second sound signal in a sound source; and setting a tone parameter corresponding to the first sound signal to the sound channel. 2. The method according to claim 1, wherein in the outputting step, a sounding instruction is issued to the sounding channel. 3. The first audio signal is a sequentially supplied audio signal, and the second audio signal generating step includes: extracting a fundamental component from the first audio signal; Generating the sound signal. 2. The method according to claim 1, further comprising: generating a wave. 4. An audio signal generator for performing the method according to claim 1. 5. A recording medium storing a program for executing the method according to claim 1. Description: