JP3876595B2 - Audio signal generating method, audio signal generating apparatus, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an audio signal generating method, an audio signal generating apparatus, and a recording medium used for an apparatus for generating a musical sound signal such as a mobile phone, an electronic musical instrument, an amusement device, and the like, and particularly suitable for a small apparatus among them. The present invention relates to an audio signal generation method, an audio signal generation device, and a recording medium.
[0002]
[Prior art]
In an electronic musical instrument, a mobile phone, an amusement device, etc., a musical sound signal is generated via a built-in or external electroacoustic transducer (speaker or the like). Here, the range of sound that can be converted has a predetermined limit. In particular, with regard to bass, only sounds up to the lowest frequency (hereinafter referred to as “lowest frequency”) defined by the lowest resonance frequency of the electroacoustic transducer can be generated.
[0003]
In order to solve this, a technique for generating “pseudo bass” is known. This is a technique using the human illusion that when an audio signal of two frequencies is generated, a signal corresponding to the greatest common divisor of both is heard. For example, in order to generate a “pseudo bass” of 100 Hz by a speaker that cannot output an audio signal of 100 Hz, if two frequencies having a maximum common divisor of 100 Hz, such as “200 Hz and 300 Hz” and “300 Hz and 400 Hz”, are generated. Good.
[0004]
For example, US Pat. No. 5,930,373 discloses details of the technology. In this technique, filtering processing is performed on components that cannot be reproduced by a speaker in digital audio signals that are sequentially supplied, and frequency components that are twice, three times,... Of these components are generated. The frequency component generated in this way and the original audio signal are added and sounded through a speaker. Japanese Patent Application No. 2000-159478 (unpublished) by the present applicant describes a technique of generating pseudo low sound waveform data in advance and storing it in a waveform memory together with normal musical sound waveform data. In this technology, in the high frequency range, only the normal musical sound waveform data is read and a musical sound signal is generated, while in the low frequency range, the normal musical sound waveform data and the pseudo low acoustic waveform data are read and mixed to generate a musical sound signal. Is disclosed.
[0005]
[Problems to be solved by the invention]
In the above technique, whether or not to generate a pseudo bass is determined based on whether or not the pitch of the musical sound 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, causing a sense of discomfort.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an audio signal generating method, an audio signal generating apparatus, 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 configuration. The parentheses are examples.
Claim 1 Waveform signal generation method In that, A waveform signal generation method for generating a waveform signal of a plurality of sound generation channels in order to generate a musical sound via an electroacoustic transducer, wherein a sound generation instruction information (note-on event) with a specified pitch is received (steps) SP2), a determination process for determining whether or not the specified pitch is equal to or lower than a predetermined boundary pitch (pseudo bass start frequency), and in the determination process, the specified pitch is the boundary pitch (pseudo bass). A first waveform signal generation process (SP52 to SP56) for generating a first waveform signal having the specified pitch, on the condition that it is determined that it is not less than the start frequency), and the specified sound in the determination process The first waveform signal is generated on the condition that it is determined that the pitch is equal to or lower than the boundary pitch (pseudo bass start frequency), and the nth overtone (where n is the specified pitch) 2 And a natural number of 4) and the second waveform signal generation step of generating (SP62, SP64, SP66) and a second n + 1-order harmonic as the second waveform signal, the designated tone pitch A coefficient generation process (SP63) for generating a coefficient that gradually decreases as the value increases; A level control process (FIG. 13: OP3, OP4) for controlling the level of the second waveform signal by multiplying the second waveform signal by the coefficient; The Executed by the processing device (20) It is characterized by that.
Furthermore, in the configuration according to claim 2, according to claim 1. Waveform signal generation method In the above Second waveform signal generation The process takes place in the sound source Second waveform signal Process of assigning sound channel to SP62 ) And the above Second waveform signal The process of setting the musical sound parameter corresponding to SP66 ).
Furthermore, in the configuration according to claim 3, according to claim 1. Waveform signal generation method In Second waveform signal generation The process includes a process of extracting a fundamental wave component from the first audio signal (fundamental wave extraction unit 93) and a process of generating harmonics of the fundamental wave component (equal loudness conversion unit 96). To do.
Further, according to claim 4 Waveform signal generator In this case, the method according to any one of claims 1 to 3 is executed.
Moreover, in the recording medium of Claim 5, the method in any one of Claim 1 thru | or 3 is carried out. Let the processor (20) execute The program is memorized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
1. First embodiment
1.1. Principle of the embodiment
1.1.1. Waveform component analysis
In the present embodiment, the musical sound waveform is stored separately as “periodic component” and “noise component”, and the details thereof will be described. When the musical sound waveform of a natural musical instrument is subjected to FFT (Fast Fourier Transform) analysis, the frequency component of the musical sound waveform can be separated into a frequency component that is continuous on the time axis and a frequency component that is intermittent on the time axis. When a waveform is synthesized based on the former frequency component, a “sound component” of a musical tone waveform is obtained, and when a waveform is synthesized based on the latter frequency component, a “noise component” of a musical tone waveform is obtained.
[0008]
An example is shown in FIG. FIG. 4A 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 noise component often has a short section with a large amplitude level and is often distributed over a wider frequency range than the periodic component of the musical sound signal. For this reason, it is rare that the characteristics of the electroacoustic transducer become a problem, and it can be understood that only the periodic component needs to generate a pseudo bass as necessary.
[0009]
1.1.2. Equal loudness curve
In human hearing, even if the sound pressure level is constant, the sound volume seems to be different if the frequency is different. Therefore, when the curve of the sound pressure level with equal sound volume (loudness) is drawn on the graph with the horizontal axis representing the frequency and the vertical axis representing the sound pressure level, it is shown in FIGS. 5 (a) and 5 (b). Such characteristics can be obtained. These characteristics are called “equal loudness curves”. Figure (a) is called "Fletcher &Manson's equal loudness curve" and is a little old. The figure (b) is called “Robinson &Dudson's equal loudness curve”, which is relatively new and adopted in ISO.
[0010]
1.2. Hardware configuration of the embodiment
Next, the 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). A coder / decoder 4 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 that displays various information to the user. Reference numeral 8 denotes an input device, which includes a numeric keyboard, direction buttons, and the like, and various information is input by the user. A sound source 10 generates a musical tone signal such as a ringing 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 musical tone signal is generated through the sound system 12. The sound system 12 includes an amplifier and an electroacoustic transducer. As the electroacoustic transducer, a speaker, a headphone, an earphone or the like can be selected, and these have different conversion characteristics.
[0011]
Reference numeral 16 denotes a MIDI interface which exchanges MIDI signals with an external MIDI device. Reference numeral 18 denotes a vibrator which 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 cellular phone device via the bus 14 based on a control program to be described later. Reference numeral 22 denotes a ROM which stores an operating system, a musical tone synthesis program, performance information predetermined for a mobile phone, and various other data. Reference numeral 24 denotes a RAM which is used as a work memory for the CPU 20 and can store performance information defined by the user. The waveform memory in the sound source 10 is backed up by a battery, and can store waveform data of user-defined timbre.
[0012]
1.3. Operation of the embodiment
1.3.1. Waveform data creation process
The waveform data used in this embodiment can be created by a personal computer or the like by a mobile phone manufacturer or user. The contents of the processing will be described with reference to FIG. FIG. 2 is a functional block diagram showing the contents of the processing program executed in the personal computer.
[0013]
In the figure, reference numeral 30 denotes material waveform data such as a recording waveform of a musical tone of a natural musical instrument, for example, which is externally input 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 cut-off components (noise components). Details of the waveform analysis unit 40 will be described with reference to FIG. Inside the waveform analysis unit 40, 42 is an FFT analysis processing unit, which performs FFT analysis processing 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 a frequency component within the range of the window function is analyzed.
[0014]
Next, the position of the window function is shifted backward by 1/8 of the pitch period on the time axis, and the frequency component is similarly analyzed. When this process is repeated for the entire original waveform data, a change in frequency component on the time axis is obtained. A continuous component separation unit 44 separates components that are continuous on the time axis from a series of frequency components. The separated component is output as a deterministic frequency component 32 and supplied to the synthesis unit 46. In the synthesizer 46, deterministic waveform data is synthesized based on the deterministic frequency component 32. A subtracting unit 48 subtracts deterministic waveform data from the material waveform data 30. This subtraction result is output as noise component waveform data 34.
[0015]
Returning to FIG. 3, reference numeral 54 denotes attack and loop information, which is set by the user with reference to the material waveform data 30. Or you may make it set automatically using the result of the said waveform analysis, etc. according to a user's specification. The contents of the attack & loop information 54 are the length of the attack portion that is read only once at the beginning of waveform reproduction, the length of the loop portion that is repeatedly read after that, and the like. Reference numeral 36 denotes a waveform synthesizer, which synthesizes the waveform data of the attack part and the loop part 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 in a hard disk of a personal computer.
[0016]
Here, an outline of synthesis processing in the waveform synthesis unit 36 will be described. First, from the attack & loop information 54, an attack start address indicating the head of the attack portion, a loop start address indicating the head and end of the loop portion, and a loop end address are determined. Next, among the deterministic frequency components of the loop part, a component that is close to the phase of the loop start at the loop end is selected, and for the selected component, the phase at the loop end matches the phase at the loop start. It is corrected to. When the loop is a long group (the loop size is several hundred milliseconds or more), a component that is not a value close to the phase of the loop start at the loop end (an anharmonic component) may be selected and corrected. Next, sine wave synthesis is performed based on the corrected frequency component, and waveform data of the loop portion is generated.
[0017]
Next, the deterministic frequency component of the attack part that is not used in the loop part is processed so that it gradually fades out from the middle of the attack part to the end of the attack part, and the processed deterministic frequency Sine wave synthesis is performed based on the components, and waveform data of the attack part is generated. Further, while the volume of the noise component waveform data 34 is controlled, this is mixed into the attack part and the loop part. The waveform data of the attack part and the loop part created as described above is a waveform that is very similar to the material waveform data 30, and has a good connection from the attack part to the loop part and from the loop end to the loop start. Become data.
[0018]
Next, 60 is a pseudo bass synthesizing unit, which includes pseudo bass start frequency data 51 indicating the highest frequency at which pseudo bass playback should be performed in the mobile phone, deterministic frequency component 32, and attack & loop information 54. Based on this, pseudo low sound waveform data 52 is generated. The pseudo bass start frequency data 51 may be a frequency set in advance according to the model of the cellular phone (or the model of headphones, earphones, etc.), or may be a frequency that can be arbitrarily set by the user. . Here, an example of a method for determining the pseudo bass start frequency data 51 will be described with reference to FIG. In the figure, the horizontal axis is the frequency or note number NN, and the cut-off frequency (minimum frequency) is determined on the figure according to the characteristics of the electroacoustic transducer of the mobile phone.
[0019]
As described above, when it is determined whether or not to generate a pseudo bass sound with this cutoff frequency as a boundary, there arises a problem that the sound quality is significantly different before and after the cutoff frequency. Therefore, in the present embodiment, a 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 is lowered, thereby alleviating the uncomfortable feeling. Specifically, the volume coefficient RVOL that increases as the frequency decreases in the range of “0 to 1” is determined as shown in the figure, and this process can be realized by multiplying the volume coefficient RVOL by the pseudo low sound waveform. The frequency at which the characteristic of the volume coefficient RVOL intersects the horizontal axis is called “pseudo bass start frequency”.
[0020]
Returning to FIG. 3, an extraction unit 67 in the pseudo bass synthesis unit 60 extracts a frequency component equal to or lower than the pseudo bass start frequency from the deterministic frequency component 32. A harmonic generation unit 62 generates a plurality of harmonic components exceeding the pseudo bass start frequency for each extracted frequency component. Here, the frequency of the extracted frequency component varies with time, and therefore the frequency of the generated harmonic component also varies accordingly.
[0021]
For example, it is assumed that 240 Hz which is one octave higher than the cutoff frequency (120 Hz) is set as the pseudo bass start frequency. In this case, harmonic components at least twice and three times as high as the frequency components of 120 <f ≦ 240 Hz in the deterministic frequency component 32 are generated. Similarly, at least 3 times and 4 times higher harmonic components for frequency components of 80 <f ≦ 120 Hz, and at least 4 times and 5 times higher harmonic components for frequency components of 60 <f ≦ 80 Hz. Will be generated.
[0022]
Next, 68 is an envelope conversion unit, which outputs the envelope of each harmonic component so that the volume feeling (loudness) of the pseudo bass generated by each harmonic component matches the volume feeling of the original frequency component. The contents will be described with reference to FIG. According to the equal loudness curves previously shown in FIGS. 5A and 5B, in order to generate the same volume feeling in the low frequency range (for example, 100 Hz) in the harmonic components (for example, 200 Hz and 300 Hz). It is understood that the level of the harmonic component must be reduced and the level change width must be increased.
[0023]
Therefore, in the envelope conversion unit 68, when the envelope level of the extracted original frequency component is the one shown in the characteristic A in FIG. 7, this is converted into the harmonic B by converting it into the characteristic B in FIG. Output as the envelope level of the wave component. In the low sound range of the equal loudness curves of FIGS. 5A and 5B, the sound pressure level of the equal loudness decreases by 10 to 15 dB every time the frequency is doubled. Accordingly, the level L1 in FIG. 7 is set to “10-15 dB × multiplier number”. In addition, the magnitude of the change in the sound pressure level at which the changes in loudness are equal is about 1.4 times in “Fletcher & Manson” and 1 in “Robinson & Dudson” every time the frequency is doubled. About 1 time. Accordingly, the level ratio L3 / L2 in the figure is set to about “1.1 to 1.4 × multiplier number”.
[0024]
Returning to FIG. 3, reference numeral 64 denotes an amplitude control unit that multiplies each harmonic component output from the harmonic generation unit 62 by the envelope level output from the envelope conversion unit 68. Reference numeral 66 denotes a plural waveform mixing unit that mixes each harmonic component to which the envelope is applied. This mixing result 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 are obtained as waveform data of a user-defined tone when a user connects a mobile phone to a personal computer and performs a predetermined operation. It is transferred to the waveform memory in the sound source 10.
[0025]
By the way, in general, in a waveform memory sound source, different normal musical sound waveform data 38 is stored for each tone range of each tone color (the waveform data may be shared between tone colors and between tone ranges). In this embodiment, among the normal musical sound waveform data, only the basic musical sound waveform data used for musical tone generation at a pitch where the fundamental wave component of the included deterministic frequency component is equal to or lower than the pseudo low frequency start frequency is the corresponding pseudo low sound. The waveform data 52 is stored in the waveform memory. Basically, the normal musical sound waveform data 38 may be stored in one-to-one correspondence, but this is not necessarily required. In some cases, a plurality of pseudo low sound waveform data may be stored for one normal musical sound waveform data, or conversely, 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, thereby realizing a desired pitch. Then, in this embodiment, the frequency component that cannot be actually reproduced by the capability of the sound system 12 among the frequency components of the normal musical sound waveform data 38 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.
[0026]
For this reason, in this embodiment, the sound range to which one pseudo low sound waveform data 52 is applied is narrower than the sound range to which one normal musical sound waveform data 38 is applied, and the number of pseudo low sound waveform data 52 is large. It tends to be. 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 for this will be explained.
[0027]
First, in general consumer equipment, the sampling frequency of the musical sound waveform is about 32 to 48 kHz, 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, the upper limit of the reproduction frequency is sufficient at about 2 kHz (although depending on the cut-off frequency), it is sufficient to secure the sampling frequency at about 5 to 10 kHz. For this reason, the data amount of one pseudo low sound waveform data 52 can be suppressed to a fraction of 1 to several tenths of one normal musical sound waveform data 38. In addition, when applying such a low sampling frequency, it is preferable to employ highly accurate inter-sample point interpolation such as “8-point interpolation”.
[0028]
1.3.2. Waveform synthesis processing
Performance information (for example, SMF (standard MIDI format) file) for reproducing a ring tone is stored in the ROM 22 and the RAM 24 in the cellular phone. When there is an incoming call to this cellular phone, the performance information is reproduced, and MIDI events are sequentially input from the CPU 20 to the sound source 10, and a musical sound waveform is synthesized in the sound source 10 based on this. The contents of the sound source control process will be described with reference to FIG.
[0029]
(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”. The flag PLE is a flag indicating the on / off state of the pseudo bass effect, where “1” indicates on and “0” indicates off. Note that the value of the flag PLE can be switched at any time by the user performing a predetermined operation.
[0030]
If the flag PLE is “0”, “NO” is determined here, and the process proceeds to step SP10. Here, the normal sound generation control subroutine shown in FIG. In the figure, when the process proceeds to step SP22, a tone generation channel for one channel is assigned in the sound source 10. The channel number of the assigned sound generation channel is set to a1.
[0031]
Next, when the process proceeds to step SP24, musical tone parameters corresponding to the tone color TC (PT) corresponding to the part number PT, the note number NN, and the velocity VEL are set for the channel number a1 in the sound source. Is done. Here, the musical sound parameters include the following.
[0032]
(1) Address information of the normal musical sound waveform data 38 (selected waveform data) corresponding to the note number NN among the plurality of normal musical sound waveform data 38 corresponding to the tone color TC (PT) stored in the waveform memory.
Since the normal musical sound waveform data 38 is generally composed of an attack part and a loop part, it is necessary to set these start and end addresses. However, depending on the tone color TC (PT), the normal musical sound waveform data 38 may be composed only of the loop portion or only one-shot waveform data. Further, different waveform data may be applied for each velocity VEL range.
[0033]
(2) F number corresponding to note number NN
In the normal musical sound waveform data 38, an original pitch OP is defined for each waveform data. When the note number NN is designated, the progress speed of the read address of the normal musical sound waveform data 38, that is, 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, that is, The F number is determined.
[0034]
(3) Volume envelope parameter
When tone color TC (PT), velocity VEL, and note number NN are designated, a volume envelope parameter for designating a volume envelope is determined in accordance with them.
(4) Other parameters
In addition, a tone color filter parameter, a pitch modulation parameter, an amplitude modulation parameter, and the like corresponding to the tone color TC (PT), the note number NN, and the velocity VEL are appropriately set.
[0035]
Next, when the process proceeds to step SP26, a sound generation start is instructed for the channel number a1 of the sound source. Thus, the process for the note-on event is completed. Thereafter, in the sound source 10, the normal musical sound waveform data 38 is read at a speed corresponding to the note number NN, and further, a filtering process according to the timbre filter parameter and a time change process of the volume according to the volume envelope parameter. And a musical tone signal related to channel number a1 is sequentially generated in a state in which no pseudo bass is included. The musical tone signal is generated via the sound system 12. Even if the musical sound signal includes a frequency component equal to or lower than the cutoff frequency, the component is not reproduced by the sound system 12, and the user cannot hear it.
[0036]
(2) When the pseudo bass effect is on
If a note-on event occurs when the pseudo bass effect is on (flag PLE = 1), the process proceeds to step SP6 via steps SP2 and SP4. Here, based on the tone color TC (PT) and the note number NN, it is determined whether or not a pseudo low sound waveform 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, so the determination is made taking into account the timbre TC (PT).
[0037]
For example, assume that the cutoff frequency is 120 Hz, the pseudo bass start frequency is 240 Hz, and the note number corresponds to the fundamental frequency as it is (no octave shift). If the reference pitch is A4 = 440 Hz, then A3 = 220 Hz, A # 3 = 233.08 Hz, and B3 = 246.92 Hz. Therefore, a pseudo low sound waveform should be generated when the pitch is A # 3 or less. I understand that there is.
[0038]
Next, when the process proceeds to step SP8, the process branches according to the determination result of step SP6. First, if it is determined that “the pseudo low sound waveform should not be generated (note number is B3 or higher)”, the process proceeds to step SP10. As a result, the normal sound generation control subroutine (FIG. 2B) is called as in the case where the pseudo bass effect is off. Accordingly, a tone generation channel for one 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.
[0039]
On the other hand, if “YES” is determined in step SP8, the process proceeds to step SP12. Here, the pseudo-bass tone generation control routine shown in FIG. 8 is called. In the figure, when the process proceeds to step SP32, two tone generation channels are assigned in the sound source 10. The channel numbers of the assigned sound generation channels are a1 and a2. Next, when the process proceeds to step SP33, the volume coefficient RVOL is determined based on the note number NN, the tone color TC (PT), and the volume coefficient characteristic (FIG. 14).
[0040]
Next, when the process proceeds to step SP34, musical tone parameters corresponding to the tone color TC (PT) corresponding to the part number PT, the note number NN, and the velocity VEL are set for the channel number a1 in the sound source. Is done. The processing contents are the same as in step SP24 described above. Next, when the processing proceeds to step SP36, a pseudo bass parameter is set in the channel number a2 corresponding to the musical sound signal generated in the channel number a1.
[0041]
Here, the following tone parameters are set for the pseudo bass.
(1) Address information of pseudo low tone waveform data 52 (selected pseudo low tone waveform data) corresponding to the normal musical tone waveform data 38 selected in step SP34.
(2) F number of the pseudo low sound waveform data 52 corresponding to the note number NN.
The F number for the pseudo low sound waveform data 52 is also determined by the same procedure as the F number of the normal musical sound waveform data 38. That is, the F number of the pseudo low sound waveform data is determined according to the difference between 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. 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 has a predetermined proportional relationship with the F number of the normal musical sound waveform data (however, the sampling frequencies are different from each other). As a result, in channel number a2, a pseudo bass sound in which the pitch and the time axis are completely synchronized with the musical sound signal generated in channel number a1 is obtained.
[0042]
(3) Volume envelope of pseudo bass corresponding to the volume envelope of channel number a1
As described with reference to FIG. 7, the volume envelope (characteristic B) of the pseudo bass is different from the volume envelope (characteristic A) of the original waveform. Accordingly, a volume envelope for pseudo bass is set by modifying the volume envelope of channel number a1.
However, in both the normal musical sound waveform data 38 and the pseudo low sound waveform data 52, waveform data whose volume envelope changes is stored in the attack portion of the attack portion and the loop portion, respectively. Therefore, in each channel of the waveform memory sound source, it is not necessary to give a temporal change in volume for the attack portion, and a volume envelope parameter for designating 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 given by the channel number a1 and a volume envelope (characteristic B ′) for the pseudo low sound waveform data 52 given by the channel number a2. Here is an example.
[0043]
Each volume envelope follows the relationship of the 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 bass start frequency included in the reproduced normal musical sound waveform data 38 and the loudness of the pseudo low sound waveform data are substantially matched, so that the characteristic B ′ is more than the characteristic A ′. The level is set low. Also, in the loop part, the loudness change amount of the component below the pseudo bass start frequency included in the loop part of the normal musical sound waveform data to be reproduced substantially matches the loudness change quantity of the loop part of the pseudo bass sound form data, The slope of B ′ is set to be steeper than the slope of characteristic A ′. As a result, in channel number a2, a pseudo low sound waveform whose loudness characteristic follows a component equal to or lower than the pseudo bass start frequency included in the musical tone signal generated in channel number a1 is obtained.
[0044]
Further, the volume coefficient RVOL is multiplied by the volume envelope of the channel number a2 obtained in this way. As a result, the change in sound quality with respect to the note number NN can be moderated around the lowest frequency, and a natural musical sound signal can be generated.
(4) Other parameters
The contents of various other parameters are basically set in the same manner as channel number a1.
[0045]
Returning to FIG. 8, when the process proceeds to step SP38, the sound generation start is instructed to the channel numbers a1 and a2 in the sound source. Thus, the process for the note-on event is completed. Thereafter, in 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 sound signal related to the channel number a1 is sequentially generated without including the pseudo bass. In synchronization with this, in the channel number a2, the pseudo low sound waveform data 52 corresponding to the note number NN is read, and pseudo bass signals are sequentially generated. As a result, both signals are generated via the sound system 12. The sound system 12 does not reproduce the component below the lowest frequency of the musical sound signal, but the user can listen to the pseudo bass corresponding to the component instead of the component not reproduced, and whether the component is reproduced. The illusion.
[0046]
As described above, according to the present embodiment, the volume envelope for the normal musical sound waveform and the volume envelope for the pseudo-low sound waveform can be individually controlled, so that the volume level and dynamics according to the equal loudness curve according to the situation at that time. It is possible to control the range.
[0047]
2. Second embodiment
Next, a second embodiment of the present invention will be described. The hardware configuration of the second embodiment is the same as that of the first embodiment, but the waveform data prepared in the waveform memory and the software configuration for control are slightly different compared to the first embodiment, so only the differences are described. explain.
[0048]
(1) Waveform data creation process
In the present embodiment, waveform data creation processing similar to that described with reference to FIGS. 3 and 4 is executed, and normal musical sound waveform data 38 and pseudo-low sound waveform data 52 are obtained. Further, in the present embodiment, the processing shown in FIG. 10 is executed.
[0049]
In the figure, reference numeral 75 denotes a volume coefficient calculation unit, which, when given a note number NN, calculates a volume coefficient RVOL based on the volume coefficient characteristic (FIG. 14). Reference numerals 72 and 74 denote amplitude control units that control the amplitude of the waveform data 38 and 52. Further, the amplitude control unit 72 multiplies the obtained amplitude by a volume coefficient RVOL. That is, a level difference corresponding to the difference between the attack portions of the characteristics A ′ and B ′ in FIG. 9 of the first embodiment is given to the envelopes of both waveform data, and then the amplitude control unit 72 further multiplies the volume coefficient RVOL. The amplitude of both waveform data is set. A mixing unit 76 mixes both waveform data whose amplitudes are controlled, and outputs the result as pseudo-low tone 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 way, 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 bass start frequency included in the normal musical sound waveform data 38, and the pseudo low sound waveform whose amplitude is controlled to be equal to the frequency component. The data was mixed, and pseudo low tone waveform data 78 was prepared.
[0050]
Here, among the contents described with reference to FIG. 7, the sound pressure level is attenuated to align the loudness of the pseudo bass, but the control of the change in the sound pressure level to align the loudness change is performed. Absent. This is because in “Robinson & Dudson”, since the ratio of the magnitudes of the changes in the sound pressure level is close to 1, it is determined that the sound pressure level may be omitted. The generated normal musical sound waveform data 38 and the corresponding pseudo-low tone waveform data 78 are transferred from the personal computer to the waveform memory in the sound source 10 of the mobile phone in accordance with a user's predetermined operation. In the waveform memory, normal musical tone waveform data 38 is stored for each tone range, but the pseudo-bass waveform data is used for generating musical tones at a pitch whose fundamental wave component is below the pseudo bass start frequency. Only the normal musical sound waveform data 38 may be prepared and stored in the waveform memory.
[0051]
(2) Note-on event processing
Also in the present embodiment, when a note-on event occurs, the note-on event processing routine shown in FIG. 2A is started as in the first embodiment. The processing 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 musical sound signal is the same as that of the first embodiment. Exactly the same. When the pseudo bass effect is on and the musical tone signal to be generated includes a frequency component equal to or lower than the pseudo bass start frequency, in step S12, the tone generation control routine with pseudo bass shown in FIG. Called.
[0052]
Steps SP42, SP44, and SP46 executed in this routine are the same as the contents of steps SP22, SP24, and SP26 (FIG. 2B) executed for the normal musical sound waveform. However, in step SP44, instead of the normal musical sound waveform data 38, address information, F number, volume envelope parameter, and other parameters for the pseudo bass waveform data 78 are set in the sound source 10. The set address information is a pseudo bass waveform corresponding to the normal musical sound waveform data 38 corresponding to the note number NN among the plurality of normal musical sound waveform data 38 corresponding to the tone color TC (PT) stored in the waveform memory. This is address information of data 78. The F number, volume envelope parameter, and other parameters may basically be the same values as the corresponding parameters of the normal musical sound waveform data 38.
[0053]
As a result, when sound generation is instructed to the channel number a1 of the sound source in step SP46, the sound source 10 reads the pseudo bass waveform data 78 at a speed corresponding to the note number NN. Then, a filter process according to the timbre filter parameter and a time change process of the sound volume according to the sound volume envelope parameter are performed, and a musical tone signal related to the channel number a1 is sequentially generated in a state including a pseudo bass. The musical tone signal is generated via the sound system 12. Since this musical tone signal includes a pseudo bass corresponding to a frequency component below the lowest frequency that cannot be reproduced, the user can hear it as if the frequency component is being reproduced. Further, even for frequency components that are higher than the minimum frequency and lower than the pseudo bass start frequency, a pseudo bass waveform is generated so that the volume coefficient RVOL increases as the frequency decreases, according to the volume coefficient characteristic (FIG. 14). The change in sound quality with respect to the note number NN can be moderated around the lowest frequency.
[0054]
According to the present embodiment, even when a pseudo bass is generated, the sound generation channel assigned to one note-on event can be suppressed to one channel. For this reason, it is particularly suitable when it is desired to suppress an increase in the number of sound generation channels.
[0055]
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 modulation sound source (FM sound source). Although the software configuration is slightly different from that of the first embodiment, only the difference will be described below.
[0056]
(1) Waveform data creation process
In the present embodiment, since the tone signal is generated by the FM sound source method, the waveform data creation processing as in the first and second embodiments is not executed.
[0057]
(2) Normal pronunciation control in note-on event processing
Also in the present embodiment, when a note-on event occurs, the note-on event processing routine shown in FIG. 2A is started as in the first embodiment. However, in this embodiment, when the pseudo bass sound should not be generated, the normal sound generation control subroutine shown in FIG. 12A is called in step SP10.
[0058]
When the process proceeds to step SP52 in FIG. 12 (a), the sound source 10 is assigned a sound channel for one channel. The channel number of the assigned sound generation channel is set to a1.
[0059]
Next, when the process proceeds to step SP54, the tone signal TC (PT) corresponding to the part number PT, the note number NN, and the velocity VEL are used for the channel number a1 in the sound source. Music parameters are set. In general, the tone parameters of the FM tone generator set for the tone generator channel are based on tone color data prepared for each tone color TC, and the note number NN and the basic tone parameter for tone signals. It is prepared by adding correction (scaling) according to the velocity VEL. Here, the musical sound parameters include the following.
[0060]
(1) Algorithm
In the FM sound source method employed in the present embodiment, an algorithm (a connection state of n operators) is selected according to the tone color TC (PT). In addition, the type of waveform data used by each operator (sine wave, half-wave rectified waveform of sine wave, full-wave rectified waveform of sine wave, etc.), and the progression speed of the phase data for generating the waveform data are controlled. Pitch data (controls the pitch of the waveform data), a multiplier for the pitch data for each operator (the speed of the phase data in each operator is controlled by the product of the multiplier and the pitch data), low frequency modulation control data (vibrato) The envelope parameters for controlling the envelope waveform applied to the waveform data generated by each operator are determined according to the tone color TC (PT), the note number NN, and the velocity VEL. As the contents of the algorithm, various kinds of contents can be considered, but as a simple example, as shown in FIG. 13 (a), “n = 2” operators OP1 and OP2 are connected in series. It is done.
[0061]
(2) Volume envelope parameter
The volume envelope of the tone signal output from the FM sound source corresponds to the envelope given to the operator at the final stage of the algorithm (OP2 in the illustrated example). As described above, the envelope parameter of the envelope is determined according to the tone color TC (PT), the note number NN, and the velocity VEL.
[0062]
(3) Other parameters
When filtering processing is performed on the output of the algorithm, timbre filter parameters corresponding to the timbre TC (PT), note number NN, velocity VEL, and the like are set. Furthermore, a pitch envelope parameter for controlling a pitch envelope for changing the pitch of the generated tone signal may be set.
[0063]
Next, when the process proceeds to step SP56, the sound generation start is instructed to the channel number a1 of the sound source. Thus, the process for the note-on event is completed. Thereafter, the tone generator 10 sequentially generates a musical tone signal related to the channel number a1 without including the pseudo bass. The musical tone signal is generated via the sound system 12. Even if the musical sound signal includes a frequency component equal to or lower than the lowest frequency, the component is not reproduced by the sound system 12, and the user cannot hear it.
[0064]
(3) Pronunciation control with pseudo bass in note-on event processing
When the process proceeds to step SP12 in the note-on event processing routine (FIG. 2A), the pseudo-bass sound generation control routine shown in FIG. 12B is called. In the figure, when the process proceeds to step SP62 in the figure, two sound generation channels are assigned in the sound source 10. The channel numbers of the assigned sound generation channels are a1 and a2. Next, when the process proceeds to step SP63, the volume coefficient RVOL is determined based on the note number NN, the tone color TC (PT), and the volume coefficient characteristic (FIG. 14).
[0065]
Next, when the process proceeds to step SP64, the tone signal TC (PT) corresponding to the part number PT, the note number NN, and the velocity signal VEL corresponding to the channel number a1 in the sound source are processed. Music parameters are set. The processing content is the same as in step SP54 described above. Next, when the process proceeds to step SP66, m operators for pseudo bass are secured in the channel number a2 corresponding to the musical tone signal generated in the channel number a1, and these parameters are set.
[0066]
Here, the following tone parameters are set for the pseudo bass.
(1) Algorithm
In order to generate a pseudo bass, an algorithm (see FIG. 13B) having a configuration in which two operators OP3 and OP4 are connected in parallel is set for channel number 2.
The frequency component of the tone signal generated in channel number a1 includes a frequency component equal to or lower than the pseudo bass start frequency. Here, it is assumed that the operator at the last stage of the channel number a1 and the operator whose pitch data is 1 generates the lowest sound of the channel. In that case, the channel number a2 is set with the pitch data of the frequency f corresponding to the note number NN as with the channel number a1, and further, the harmonics of the frequency f are set by appropriately setting the multipliers for each operator of the channel number a2. The Occurrence To do. In each operator, a combination of a plurality of multipliers (for example, “2, 3”, “3,4”) such that the pitch of the waveform data to be generated is larger than the pseudo bass start frequency and the greatest common divisor is “1”. ,...) Are set, and the pitch frequency of the actually generated signal becomes “2f, 3f”, “3f, 4f”,.
[0067]
(2) Volume envelope parameter
When the tone color TC (PT), velocity VEL, and note number NN are designated, a volume envelope parameter is determined in order to designate a volume envelope to be given to a pseudo bass operator (OP3, OP4 in the illustrated example). The The relationship between the volume envelopes in both channel numbers a1 and a2 is the same as in the first and second embodiments. That is, a volume envelope having an equal loudness relationship with a volume envelope of a low frequency component included in the musical tone signal generated in the channel a1 and having a frequency equal to or lower than the pseudo bass start frequency is obtained, and each of them is multiplied by a volume coefficient RVOL. Envelope parameters are set for the two operators of channel number a2. Here, the envelope parameters set for each operator are different from each other according to the pitch of the waveform data to be generated.
[0068]
(3) Other parameters
In addition, a tone color filter parameter corresponding to the note number NN and velocity VEL is set. When the pitch envelope is set for the channel number a1, by setting the same pitch envelope for the channel number a2, a pseudo bass pitch generated by the channel number a2 is generated by the channel number a1. It is possible to follow the pitch variation of the musical sound signal. Here, the tone parameter for the pseudo bass described above can be created in the same manner as the tone parameter for the tone signal. Specifically, first, the tone color data prepared for each tone color TC includes pseudo bass data. Then, correction (scaling) according to the note number NN and velocity VEL is applied to the basic musical sound parameter for pseudo bass included in the tone color data, thereby creating a musical parameter for pseudo bass.
[0069]
Returning to FIG. 12B, when the process proceeds to step SP58, the start of sound generation is instructed to the channel numbers a1 and a2 in the sound source. Thus, the process for the note-on event is completed. Thereafter, in the channel number a1 of the sound source 10, musical tone signals are sequentially generated without including pseudo bass. In synchronization with this, a pseudo bass signal corresponding to the note number NN is sequentially generated in the channel number a2. When both signals are sounded through the sound system 12, the user is not able to reproduce the sound signal of the channel number a1 due to the pseudo bass sound of the channel number a2 even though the frequency component below the lowest frequency is not reproduced. An illusion that the frequency component is heard. Further, even for frequency components that are higher than the minimum frequency and lower than the pseudo bass start frequency, a pseudo bass waveform is generated so that the volume coefficient RVOL increases as the frequency decreases, according to the volume coefficient characteristic (FIG. 14). The change in sound quality with respect to the note number NN can be moderated around the lowest frequency.
[0070]
4). Fourth embodiment
Next, a fourth embodiment of the present invention will be described. The hardware configuration of the fourth embodiment is the same as that of the third embodiment, but the software configuration is slightly different from that of the third embodiment, so only the differences will be described.
[0071]
(1) Pronunciation control with pseudo bass in note-on event processing
In the present embodiment, when the processing proceeds to step SP12 in the note-on event processing routine (FIG. 2 (a)), a tone generation control routine with pseudo-bass shown in FIG. 12 (c) is called. In the figure, when the process proceeds to step SP72, a tone generation channel for one channel is assigned in the sound source 10. The channel number of the assigned sound generation channel is set to a1. Next, when the process proceeds to step SP73, the volume coefficient RVOL is determined based on the note number NN, the tone color TC (PT), and the volume coefficient characteristic (FIG. 14).
[0072]
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 that can change the number of operators for each channel is used. “M” and “n” are the numbers of operators for normal tone generation and pseudo bass in the third embodiment. Next, musical tone parameters corresponding to the tone color TC (PT) corresponding to the part number PT, the note number NN, and the velocity VEL are set.
[0073]
The algorithm set here is equivalent to the algorithm for normal sound generation in the third embodiment and the algorithm for pseudo bass sound connected in parallel. An example of this is shown in FIG. The other musical tone parameter settings are the same as in the third embodiment.
[0074]
Next, when the process proceeds to step SP76, the sound generation start is instructed to the channel number a1 in the sound source. Thus, the process for the note-on event is completed. Thereafter, in the channel number a1 of the sound source 10, musical tone signals including pseudo bass are sequentially generated.
[0075]
As described above, the difference between the third and fourth embodiments is whether to secure two sound generation channels or one channel when performing sound control with pseudo-bass. Which embodiment is selected may be determined based on whether or not 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 (FIG. 13 (a) + (b)) must be adopted. Further, any embodiment can be adopted as long as the maximum number of operators is “4” or more, but it is more advantageous to adopt the fourth embodiment in that the number of channels can be suppressed.
[0076]
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, the same processing as step SP2 and step SP10 in FIG. 2A (steps SP22 to SP26 in FIG. 2B) is executed. That is, in the present embodiment, the software processing is not changed based on whether or not the pseudo bass is generated.
[0077]
Here, the configuration of the sound source 10 in the present embodiment will be described with reference to FIG. In FIG. 9A, reference numeral 82 denotes a normal musical tone signal generator, which generates a normal musical tone signal that does not include a pseudo bass based on the note number NN, tone color TC (PT), and velocity VEL. The normal music signal generator 82 may generate a music signal by any method such as a waveform memory sound source or FM sound source. A pseudo bass generator 84 generates a pseudo bass signal in real time with respect to the normal tone signal sequentially output from the normal tone signal generator 82.
[0078]
Here, the detailed configuration of the pseudo bass generator 84 will be described with reference to FIG. In the figure, reference numeral 92 denotes an LPF, which extracts components below the pseudo bass start frequency from the normal musical tone signal. Reference numeral 93 denotes a fundamental wave extraction unit that extracts a fundamental wave component from the output signal of the LPF 92. A harmonic generation unit 94 generates harmonics of the fundamental wave component. For example, when the frequency of the fundamental wave component is f, the harmonic generation unit 94 extracts 2f, 3f, 4f,. Reference numeral 96 denotes an equal loudness converting unit that adjusts the amplitude of each harmonic component so as to exhibit the same volume feeling as that of the fundamental wave component according to an equal loudness curve. Reference numeral 98 denotes an adder, which adds each harmonic component whose amplitude is adjusted.
[0079]
Returning to FIG. 14A, 86 is a coefficient generator, which outputs a volume coefficient RVOL based on the note number NN and tone color TC (PT) supplied to the sound source 10 and the volume coefficient characteristic (FIG. 14). To do. A multiplication unit 85 multiplies the pseudo bass signal output from the pseudo bass generation unit 84 by a volume coefficient RVOL. Reference numeral 88 denotes a mixer that mixes the normal musical tone signal and the pseudo bass signal and outputs the mixed signal to the sound system 12.
[0080]
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 generator 82, the sound generation channel and the tone generation slot are sacrificed for the pseudo bass generation. And pseudo bass can be generated. Further, even for frequency components that are higher than the minimum frequency and lower than the pseudo bass start frequency, a pseudo bass waveform is generated so that the volume coefficient RVOL increases as the frequency decreases, according to the volume coefficient characteristic (FIG. 14). The change in sound quality with respect to the note number NN can be moderated around the lowest frequency.
[0081]
6). Modified example
The present invention is not limited to the above-described embodiment, and various modifications can be made as follows, for example.
(1) Each of the above embodiments is the implementation of the present invention 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, software used for these can be stored in a recording medium such as a CD-ROM or a floppy disk and distributed, or distributed through a transmission path.
[0082]
(2) In the fifth embodiment, the coefficient generator 86 calculates the volume coefficient RVOL based on the note number NN and the timbre TC (PT), but instead of this, the fundamental wave component extracted by the fundamental wave extractor 93 May be used. According to such a configuration, the volume coefficient RVOL can be determined without using a tone parameter peculiar to a sound source, so that an audio signal output from a source other than the sound source (for example, record, CD, cable / wireless broadcasting, magnetic tape, etc.) On the other hand, an appropriate pseudo-bass can be given and can be applied to a wide range.
[0083]
(3) In each of the above embodiments, a frequency (240 Hz) that is 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. For example, the frequency may be set to a frequency that is 1/2 octave higher or 1/4 octave higher than the lowest frequency.
[0084]
(4) In the above embodiment, a high-pass filter that attenuates a frequency component below the lowest frequency that can be reproduced by the sound system is interposed between the sound source 10 and the sound system 12, and a frequency component below the lowest frequency that can be reproduced. May be cut. Thereby, the power consumption of the amplifier in the sound system 12 can be reduced.
[0085]
(5) When the sound source 10 is a PCM sound source having a waveform RAM, a pseudo low sound waveform may be generated by analyzing existing waveform data. At that time, the user may select or designate the pseudo bass start frequency, and the pseudo bass waveform data may be automatically created based on the selected or designated pseudo bass start frequency.
[0086]
(6) When the present invention is applied to an electronic musical instrument, when it is incorporated into an electronic musical instrument equipped with a sound system, it is preferable that a maker side sets in advance a pseudo bass effect that matches the sound system. Even in such a case, a plurality of settings may be prepared on the manufacturer 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 (such as 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, setting of the pseudo bass start frequency, minimum frequency, attenuation amount, amplitude compression amount, etc. of the pseudo bass effect may be performed by a panel of an electronic musical instrument or a personal computer equipped with a sound board.
[0087]
(7) In the above embodiment, the parameters for generating the pseudo bass are the pseudo bass start frequency, the attenuation (level L1 in FIG. 7), and the amplitude compression amount of the pseudo bass (level ratio L3 in the figure). / L2) was used. However, the attenuation amount and the amplitude compression amount 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 attenuation amount and the pseudo bass start frequency without considering the amplitude compression change in the pseudo bass.
[0088]
(8) In the above embodiment, when any one of a plurality of sound systems is switched and used, the pseudo bass start frequency for each sound system is stored in advance, and the switching status of the sound system to be used is stored. In response to this, the pseudo bass effect may be automatically set.
[0089]
(9) Control data (pseudo bass control data) for performing pseudo bass control may be included in a part of tone color data of each tone color. Further, the tone color data may include a plurality of pseudo bass control data corresponding to different lowest frequencies. In that case, if the user designates the minimum frequency of the sound system 12 in advance, then it is possible to automatically select and use the pseudo bass control data that matches the minimum frequency by simply selecting the tone. become.
[0090]
(10) In the third and fourth embodiments using an FM sound source, an algorithm in which two operators are connected in parallel is used to generate a pseudo bass sound, but other algorithms may be used.
For example, when using an algorithm in which two operators are connected in series, pitch data having the same pitch as the frequency of the low-frequency component that is not reproduced is set, and the operator on the modulator side uses the multiplier “1” to generate a waveform having the same pitch as that frequency. Data is generated, and the operator on the carrier side may generate waveform data having a pitch twice the frequency by a multiplier “2”. By applying frequency modulation to the waveform data with the same pitch as the waveform data with the double pitch, sideband frequency components are generated at intervals of frequencies corresponding to the same pitch with the double pitch as the center. To do. A pseudo bass sound can be generated by using the carrier component having the double pitch and the side band component (having a pitch that is three times the frequency of the low frequency component that is not reproduced).
[0091]
In this case, the volume ratio between the carrier component and the one sideband component above is determined by the output level of the operator on the modulator side. In order to facilitate control, it is preferable that the envelope of the operator on the modulator side is not changed over time, that is, the volume ratio is set to a fixed value.
For the envelope of the carrier-side operator, an envelope parameter may be set so as to change over time while maintaining the relationship between the volume of the low frequency component not reproduced and the equal loudness.
[0092]
(11) In the above embodiment, the pseudo bass 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 system or a partial sound synthesis system, 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, overtones generated by ring modulation of two series of oscillators can be used for pseudo bass. If the sound source is capable of nonlinear conversion of the waveform data, a pseudo bass can be generated based on the harmonics generated by the nonlinear conversion. In addition, you may apply to a physical model sound source and an analog modeling sound source.
[0093]
(12) In the above embodiment, the pseudo bass effect can be turned on / off, but may be always on.
[0094]
【The invention's effect】
As described above, according to the present invention, the first or second waveform signal is determined by determining whether or not the designated pitch is equal to or less than a predetermined boundary pitch related to the electroacoustic transducer. Therefore, it is possible to generate a pseudo bass while reducing a necessary calculation amount.
[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 is a flowchart of (a) a note-on event processing routine and (b) a normal sound generation control subroutine.
FIG. 3 is a block diagram showing the contents of waveform data creation processing in the first embodiment.
FIG. 4 is a block diagram showing the contents of waveform data analysis processing 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 control routine with pseudo bass in the first embodiment.
FIG. 9 is a diagram showing an example of a volume envelope in the first embodiment.
FIG. 10 is a block diagram showing a main part of waveform data creation processing in the second embodiment.
FIG. 11 is a flowchart of a tone 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 in the third and fourth embodiments.
FIG. 14 is a diagram illustrating a 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 section, 3 …… Microphone, 4 …… Corder / decoder, 6 …… Display, 8 …… Input device, 10 …… Sound source, 12 …… Sound system, 14… Bus, 16 …… MIDI Interface: 18: Vibrator, 20: CPU, 22: ROM, 24: RAM, 30: Material waveform data, 32: Deterministic frequency component, 34: Noise component waveform data, 36: Waveform Synthesizer, 38 ... Normal musical sound waveform data, 40 ... Waveform analyzer, 42 ... FFT analysis processor, 44 ... Continuous component separator, 46 ... Synthesizer, 48 ... Subtracter, 51 ... Pseudo Bass start frequency data, 52 …… Pseudo bass waveform data, 54 …… Attack & loop information, 60 …… Pseudo bass synthesis unit, 62 …… Harmonic wave generation unit, 64 …… Amplitude control unit, 66 …… Multiple waveform mixing Part, 67 ... Extraction unit 68... Envelope conversion unit 72, 74... Amplitude control unit 75. Volume coefficient calculation unit 76... Mixing unit 78 .. Pseudo bass waveform data 82. , 84... Pseudo bass generator, 85... Multiplier, 86 .. coefficient generator, 88... Mixer, 92... LPF, 93 .. fundamental wave extractor, 94. ... Equal loudness conversion section, 98 ... Addition section.

Claims (5)

A waveform signal generation method for generating waveform signals of a plurality of sound generation channels in order to generate a musical sound via an electroacoustic transducer,
A process of receiving pronunciation instruction information with a specified pitch;
A determination step of determining whether or not the specified pitch is equal to or lower than a predetermined boundary pitch;
A first waveform signal generating step for generating a first waveform signal having the specified pitch, on the condition that it is determined in the determination step that the specified pitch is not less than or equal to the boundary pitch;
The first waveform signal is generated on the condition that the specified pitch is determined to be equal to or lower than the boundary pitch in the determination process, and the nth harmonic (n) Is a natural number of 2 to 4) and the (n + 1) th overtone as a second waveform signal, a second waveform signal generation process;
A coefficient generation process for generating a coefficient that gradually decreases as the specified pitch increases;
A waveform signal generation method, wherein a processing device executes a level control process for controlling the level of the second waveform signal by multiplying the second waveform signal by the coefficient . The second waveform signal generation process includes:
Assigning a sound channel for the second waveform signal in a sound source;
The waveform signal generation method according to claim 1, further comprising: setting a musical tone parameter corresponding to the second waveform signal in the sound generation channel. The second waveform signal generation process includes:
Extracting a fundamental wave component from the first audio signal;
The waveform signal generating method according to claim 1, further comprising: generating harmonics of the fundamental wave component. 4. A waveform signal generating apparatus that executes the method according to claim 1. A recording medium storing a program for causing the processing apparatus to execute the method according to claim 1.

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