Patent Application
20090031886
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2001-200373, filed Aug. 1, 2007, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a resonance sound adding apparatus for a keyboard instrument.
2. Description of the Related Art
In an acoustic piano, a string which is struck by a hammer of a keyboard resonates with a string of another tone in a state in which a damper pedal is pressed and damping of strings is released. By way of example, an electronic piano has functions of generating a resonance sound which imitates a resonant state between strings of the acoustic piano, adding the generated resonance sound to the sound having a pitch of a pressed key, and outputting resulting sound.
Jpn. Pat. Appln. KOKAI Publication No. 06-149245 discloses an apparatus that, in response to pressing of a damper pedal, changes an envelope for direct sound and an envelope for resonance sound, and changes sound volume. The envelope for the direct sound is attached to a waveform of a direct sound and the envelope for resonance sound is attached to a waveform of a resonance sound, which a musical sound corresponding to a state in which the damper pedal is pressed is generated.
Further, an apparatus for generating resonance data of sound signal data is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-311957. The apparatus includes a plurality of delay units coupled in series, provides a resonance coefficient to the respective delay units, and multiplies delayed musical signal data by a delay coefficient to generate the resonance data.
Furthermore, it has been proposed an apparatus that, when a pedal other than a damper pedal is pressed, generates a musical sound containing the pedal effect. For example, Jpn. Pat. Appln. KOKAI Publication No. 05-80749 discloses an apparatus that includes first to third groups of sound sources and a group of not-struck-string sound sources. The sound sources of the first to third groups store sound data of struck strings. The not-struck-string sound sources store sound data of strings which are not struck. When a shift pedal is pressed, the apparatus reads data from the group of not-struck-string sound sources in place of the second and third groups of sound sources and also changes filtering characteristics, thereby generating a musical sound containing a shift pedal effect.
However, the above techniques disclosed in Jpn. Pat. Appln. KOKAI Publication No. 06-149245 and Jpn. Pat. Appln. KOKAI Publication No. 05-80749 need to store a large amount of data to provide sound sources for generating the pedal effect (e.g., for storing waveform data of a resonance sound or sound data of not struck strings).
In the apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-311957 does not require another sound source for a resonance sound because resonance data of a specific resonant frequency is generated based on original sound signal data, and the generated resonance data is attached to the original sound signal data.
Hereinafter a device that produces a resonance sound of one resonant frequency will be referred to as a resonator. In the case where as many resonators as the number of keys or the number of strings including sub-strings are provided, respective resonance intensities can be appropriately controlled in such a manner that respective resonators generate items of resonance data based on resonant frequencies of the respective strings.
However, the number of resonators which can be provided has a limit. Therefore, an intensity of a resonance sound varies depending on a pitch of a musical sound to be generated, and a resonance sound of a specific resonant frequency at a specific pitch is emphasized. As a result, a harsh resonance is generated.
According to an embodiment of the present invention, a resonance sound adding apparatus for a keyboard instrument comprises:
a resonator group comprising resonators and a first adder, the resonators generating resonance sound data of given resonant frequencies based on sound signal data corresponding to a pitch of a key which is struck, each of the resonators including a delay circuit configured to delay an input based on delay time data indicating a delay time, a second adder configured to add an output from the delay circuit to input sound signal data, and a first low-pass filter configured to receive an output from the second adder and to perform low-pass filtering by a cutoff frequency depending on a filter control signal on the output from the second adder, and an output from the first low-pass filter inputting to the delay circuit, and the first adder adding outputs from the resonators;
a third adder configured to add the sound signal data and an output from the resonator group;
a storage device configured to store a coefficient table containing items of delay time data to be provided to each of the resonators; and
a delay controller configured to read different items of the delay time data from the coefficient table and supply the different items of the delay time data to the resonators;
wherein the items of the delay time data do not match with frequencies corresponding to pitches of keys of the keyboard instrument.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present invention in which:
Embodiments according to the present invention will now be explained with reference to the accompanying drawings.
The CPU 12 executes control over the entire keyboard instrument 10. The CPU 12 also executes detection of key pressing operation of the keyboard 14 and operation of the group of operation members 16. Moreover, the CPU 12 executes detection of on or off state of the damper pedal 18 and also a pressing extent of the damper pedal 18. The CPU 12 further executes control over the sound generator 20 and the resonance sound adding device 22 based on results of the above detections. When tuning of a musical sound to be generated is changed in response to an operation of any of the operation members, the CPU 12 calculates values to be stored in a coefficient table in the storage device 26.
The CPU 12 can detect riot only on or off state of the damper pedal 18 but also the degree of pressing (damper level) of the damper pedal 18. For example, the CPU 12 can detect a state of the pressed damper pedal (degree of damping) by 128 levels (0 [damper pedal off] to 127 [damper pedal fully on]).
Upon receiving pitch information of a struck key from the CPU 12, the sound generator 20 reads waveform data from a waveform memory in the storage device 26, and generates and outputs sound signal data of the pitch of the struck key. In the present embodiment, sound signal data is output in two systems, i.e., right and left channels.
The resonance sound adding device 22 receives the sound signal data, generates data of a resonance sound (resonance data) based on the sound signal data, and adds the generated resonance data to the sound signal data.
The sound system 24 includes an amplifier and a speaker. The sound system 24 outputs an acoustic signal based on the sound signal data with the resonance sound attached thereto.
The resonance sound adding device 22 also includes a filter controller 43 and a delay controller 44. The filter controller 43 reads filter control data F of resonators based on the damper level from the storage device 26. The delay controller 44 reads predetermined delay time data D from a coefficient table in the storage device 26. The delay time data D from the delay controller 44 enables adjustment of a resonant frequency of resonance data output from the resonators, and the filter control data F from the filter controller 43 enables adjustment (suppression) of a resonance level of the resonators.
Moreover, the resonance sound adding device 22 includes the gain controller 45 which controls gains of the amplifiers 32, 39, and 40.
In
The first and second resonator groups 33 and 34 generate resonance sounds based on the input data, and generate resonance data which imitates a resonance phenomenon between strings of a piano.
Items of output data from the first and second resonator groups 33 and 34 are subjected to tone adjustment by the first and second filters 35 and 36, and then amplified by the amplifiers 39 and 40, respectively. The items of data, which are tone-adjusted and amplified, are added to original items of sound signal data of the two systems (output from the amplifiers 37 and 38) and output.
The first and second filters 35 and 36 are provided with the objective of imitating tone changes and echoes which are owing to a body structure of the piano. The first and second filters 35 and 36 can be realized by combining some of a low-pass filter (LPF), a high-pass filter (HPF), and an all-pass filter. For example, the first filter 35 and the second filter 36 may have a configuration in which the LPF and the HPF are connected in series.
As shown in
The first resonator group 33 includes an adder 55 which adds outputs from the resonators 50-1 to 50-5. In the present embodiment, the resonators 50-1 to 50-5 are arranged in parallel, and resonance data is generated by adding outputs from the resonators 50-1 to 50-5. The respective resonators 50-1 to 50-5 imitate resonance vibration of strings of the acoustic piano. When designating any one of the resonators 50-1 to 50-5 rather than a specific one of them, it will be simply referred to as a resonator 50.
As shown in
Delay time data D from the delay controller 44 is supplied to the delay circuit 51. The delay time data D determines a delay time of the filter. Adjusting the delay time data D enables control of a resonant frequency of a resonance sound to be generated in the resonator 50. A resonance sound corresponding to a resonant state of a long string can be obtained when the delay time data D that makes a delay time longer is supplied. Moreover, a resonance sound corresponding to a resonant state of a short string can be obtained when the delay time data D that shortens the delay time is supplied.
Filter control data E from the filter controller 43 is supplied to the LPF 53. The filter control data F determines a cutoff frequency of the LPF 53 and can adjust intensity of resonance. In general, when a string is stimulated from the outside and starts vibration, attenuation proceeds quickly when the frequency of the vibration is high; however, the vibration corresponding to a low frequency continues longer. The LPF 53 is provided to imitate such phenomena.
Since a plurality of damper levels are provided as the degree of damping (128 levels in the present embodiment), the degree of damping (damper level) is changed depending on the pressed extent of the damper pedal 18. A change in vibration state of a string can be imitated by using the filter control data F depending on the damper level. In a state in which the damper pedal 18 is released (off state), strings of the piano are pressed by felt equipment called dampers and the strings hardly vibrates in response to external stimulation. However, pressing the damper pedal 18 gradually isolates the dampers from the strings; therefore, the strings come more likely to vibrate and resonate. Such a phenomenon is replicated by using the filter control data F associated with the damper level to change a cutoff frequency of the LPF 53.
A resonant frequency of the resonator according to the present embodiment will now be explained. In the present embodiment, lower resonant frequencies (fL1 to fL5) are supplied to the first resonator group 33, and resonance sounds of lower frequencies are generated. Higher resonant frequencies (fR1 to fR5) are supplied to the second resonator group 34, and resonance sounds of higher frequencies are generated. That is, a maximal value among fL1 to fL5 is smaller than a minimum value among fR1 to fR5. As a result, a resonance sound of a low pitch string is output from the left channel and a resonance sound of a high pitch string is output from the right channel; therefore, a sense of spreading resonance sounds like an actual grand piano can be provided. Furthermore, the resonant frequencies fL1 to fL5 are different from each other, and the resonant frequencies fR1 to fR5 are likewise different from each other.
The delay time D is an inverse number of a resonant frequency f (fL1 to fL5 and fR1 to fR5). Therefore, items of delay time data respectively corresponding to different delay times DL1 (=1/fL1) to DL5 (=1/fL5) are supplied to the delay circuits 51 of the resonators 50-1 to 50-5 in the first resonator group 33. Likewise, items of delay time data respectively corresponding to different delay times DR1 (=1/fR1) to DR5 (=1/fR5) are supplied to the delay circuits of the resonators in the second resonator group 34.
As explained above, in the case where the resonant frequency matches with the pitch of a specific key, resonance is intensified merely when a certain key is struck, and a harsh resonance sound may be generated. Thus, in the present embodiment, the resonant frequencies of resonators are set not to match with a pitch of any key.
Assuming that a frequency of an A4-key is 440 Hz, pitches (frequencies) and cycles of keys in one octave from C3 to B3 are shown in
For example, when a delay time of a given resonator is set to approximately 3.8 ms, a harsh resonance sound is generated when a key of C4 (corresponding cycle is 3.822 ms) is struck.
In the present embodiment, a coefficient table storing delay times as shown in
The coefficient table 501 which is shown in
D=1/(Freq(pitch_name)+Freq(pitch_name)*2̂(1/12))*1000
In this example, delay time data D corresponds to an inverse number of an intermediate frequency between pitches of keys adjacent to each other.
Alternatively, delay time data D may have the following relationship with respect to a pitch (or frequency) of a key which is denoted by “Freq(pitch_name)”.
D=(1/(Freq(pitch_name)×1000+1/(Freq(pitch_name)*2̂(1/12)×1000)/2
In this example, delay time data D corresponds to an intermediate value between inverse numbers of pitches of keys adjacent to each other.
In the examples shown in
In the present embodiment, the first and second resonator groups 33 and 34 respectively include five resonators, by way of example. Therefore, it is sufficient that one coefficient table stores five values selected from the items of delay time data in the coefficient table 501, and the other coefficient table stores also five values selected from the items of delay time data in the coefficient table 502.
In the present embodiment, when tuning keeps a standard state (frequency of reference sound A4 takes 440 Hz), coefficient tables 601 and 602 stored in the storage device 26 are utilized. The delay controller 44 acquires delay times from the coefficient table 601, and supplies the delay times DL1 to DL1 from the coefficient table 601 to the resonators 50-1 to 50-5 of the first resonator group 33. Furthermore, the delay controller 44 acquires delay times from the coefficient table 602, and supplies the delay times DR1 to DR5 from the coefficient table 602 to the resonators of the second resonator group 34.
The case in which the pitches (tuning) of keys are changed (pitches are controlled) will be explained later.
The filter control data F will now be explained. In the present embodiment, the cutoff frequency of the LPF 53 is changed in accordance with 128 levels of damping, from level 0 to level 127. The filter control data F on each damper level is stored in the storage device 26 as a filter control data table.
In the example shown in
Operation of thus configured resonance sound adding device 22 will now be explained hereinafter. When a player of the keyboard instrument operates the keyboard 14 and strikes a key, information of the struck key is transmitted to the CPU 12 from the keyboard 14. The CPU 12 supplies pitch information of the struck key to the sound generator 20. The sound generator 20 reads waveform data from the waveform memory in the storage device 26, and generates and outputs sound signal data based on the pitch of the struck key.
In the case where the damper pedal 18 is being pressed, the CPU 12 supplies a damper level indicative of the pressed state of the damper pedal 18 to the resonance sound adding device 22. It is to be noted that, when the damper pedal 18 is in the OFF state, the CPU 12 supplies a damper level zero indicating that the damper level is off to the resonance sound adding device 22.
As shown in
The delay controller 44 reads the delay time data D that is to be supplied to the first resonator group 33 from the coefficient table 601 in the storage device 26. Moreover, the delay controller 44 also reads the delay time data D that is to be supplied to the second resonator group 34 from the coefficient table 602 in the storage device 26.
The filter controller 43 reads predetermined filter control data F from the filter control data table stored in the storage device 26 based on the damper level supplied from the CPU 12.
In the first resonator group 33, the respective resonators (five resonators 50-1 to 50-5 in the present embodiment) delay signals based on the delay times D (DL1 to DL5) supplied from the delay controller 44 and perform filtering processing on the signals in accordance with the filter control data F. Respective items of data output from the resonators are added in the adder 55, output from the first resonator group 33, and supplied to the first filter 35.
Likewise in the second resonator group 34, the respective resonators (five resonators in the present embodiment) delay signals based on the delay time data D (DR1 to DR5) supplied from the delay controller 44 and perform filtering processing on the signals in accordance with the filter control data F. Respective items of data output from the resonators are added in the adder 55, output from the second resonator group 34, and supplied to the second filter 36.
An output from the first filter 35 passes through the amplifier 39, and then is added to the sound signal data of the left channel in the adder 41 to be output. In addition, an output from the second filter 36 is added to the sound signal data of the right channel in the adder 42 and output.
As described above, for each of the left channel and the right channel, the sound signal data having an added resonance sound which bases on delay time data and the damper level of the damper pedal 18 can be obtained. The sound signal data having the resonance sound added thereto is supplied to the sound system 24. The sound system 24 performs digital-to-analog conversion and amplification on the sound signal data, and generates an acoustic signal based on the sound signal data. The generated signal is output from the speaker.
There may be a case in which operation of an operation member in the group of operation members 16 changes tuning of the keyboard instrument 10. In the present embodiment, a reference sound is set to A4 and the pitch (frequency) of the reference sound A4 is set to 440 Hz by way of example. A player can operate the operation member to change the pitch of the reference sound within a predetermined range. The CPU 12 also changes the pitch (frequency) of each key in accordance with the change in tuning and supplies pitch information indicative of a changed frequency to the sound generator 20.
An example where the reference sound A4 is changed from 440 to 450 Hz will now be considered.
As shown in
Thus, in the present embodiment, when tuning is changed, delay time data that does not match with cycles corresponding to pitches of any keys is calculated, and a coefficient table storing the calculated delay time data is saved in the storage device 26.
As a result, immediately after tuning is changed, resonance data is not added to the sound signal data, and the sound signal data alone is output. Therefore, it can be avoided that using the original delay time data causes a resonance phenomenon generating a harsh resonance sound.
Then, the CPU 12 acquires the pitch of the reference sound involved with the change in tuning (step 903). For example, acquiring the pitch of the reference sound can be realized by calculating the pitch (frequency) of a new reference sound based on how the operation member is operated. In the foregoing example, the pitch of the new reference sound is 450 Hz.
The CPU 12 calculates pitches of predetermined keys required to calculate delay times that should be stored in the coefficient tables (step 904). For example, when such coefficient tables as shown in
Subsequently, the CPU 12 calculates delay times that should be stored in the coefficient table based on pitches adjacent to each other and calculated in step 904 (step 905).
As explained above, each delay time can be calculated based on the following expression. The “adjacent_pitch_name” denotes a pitch name of a key adjacent to the key that is corresponding to “pitch_name.”
D=1/((Freq(pitch_name)+Freq(adjacent_pitch_name))/2)*1000
The CPU 12 stores calculated delay time data into the coefficient table in the storage device 26 (step 906). Values in the coefficient table in the storage device 26 may be rewritten. Alternatively, a new coefficient table different from the original coefficient table may be generated in the storage device 26.
The CPU 12 informs the resonance sound adding device 22 of a fact that the new coefficient table is generated (step 907). For example, in step 907, an address of the new coefficient table in the storage device 26 is informed. In the case where the values in the coefficient table are rewritten, step 907 may be omitted. The delay controller 44 in the resonance sound adding device 22 can read the delay time data from the new coefficient table in accordance with the information.
Then, the CPU 12 instructs the resonance sound adding device 22 to cancel muting (step 908). Upon accepting the muting canceling instruction, the gain controller 45 in the resonance sound adding device 22 restores the gains of the amplifiers 32, 39, and 40.
Since the gain of the amplifier 32 has been set to zero and the first and second resonator groups 33 and 34 have been initialized, a harsh resonance sound is not generated even though the gains of the amplifiers 32, 39, and 40 are restored. Further, since the delay controller 44 can read the delay times from the coefficient table having the appropriate delay times stored therein, an unnecessary resonance phenomenon does not occur.
According to the present embodiment, since items of the delay time data stored in the coefficient table do not match with any cycles corresponding to pitches of the keys, it is possible to avoid occurrence of a resonance phenomenon resulting in generation of a harsh resonance sound when a specific key is struck. Accordingly, when any key is struck, an appropriate resonance sound is added to the sound signal data.
In the present embodiment, provided are the first resonator group 33 that generates the first resonance data based on the sound signal data for the left channel and the second resonator group 34 that generates the second resonance data based on the sound signal data for the right channel. Moreover, delay times indicated by items of the delay time data for respective resonators in the first resonator group 33 are larger than delay times indicated by items of the delay time data for respective resonators in the second resonator group 34. As a result, a resonance sound having a lower frequency is added to a sound signal of the left channel, and a resonance sound having a higher frequency is added to a sound signal of the right channel. Therefore, a sense of spreading resonance sounds can be provided.
Further in the present embodiment, the damper level rises as the pressed extent of the damper pedal 18 (damper level) increases. The filter control signal is generated based on the damper level, that is, a cutoff frequency increases as the damper level rises. As a result, an intensity of resonance can be appropriately adjusted in accordance with the pressed state of the damper level.
Furthermore in the present embodiment, when pitches of keys (tuning) are changed, new delay time data is calculated in accordance with a degree of the pitch-change. The newly calculated items of delay data do not match with any cycles corresponding to the changed pitches of the keys. As a result, even though the tuning is changed, occurrence of a resonance phenomenon which results in generation of a harsh resonance sound responsible for striking a specific key can be avoided.
Moreover, in the present embodiment, provided is the gain controller 45 that adjusts a gain of sound signal data input to the resonator groups 33 and 34, and adjusts a gain of resonance data to be added to the sound signal data. In response to a change in the pitches of the keys, the gain controller 45 makes a gain of the sound signal data which is to be input to the resonator groups into zero, and makes gains of the resonance data which is to be added to the sound signal data into zero; and the gains are restored when new delay time data is generated.
Making the gain of the sound signal data, which is to be input to the resonator groups, into zero in response to a change in the pitches of the keys enables initialization of resonators. Moreover, making the gains of the resonance data, which is to be added to the sound signal data, into zero can prevent harsh resonance data from being added to the sound signal data with the change in pitch of the key. In addition, when new delay data is generated, harsh resonance data is not added to the sound signal data because resonators have been initialized even though the gains are restored.
A second embodiment according to the present invention will now be explained. According to the second embodiment, an HPF is subsequently connected to an LPF in a resonator. In addition, a cutoff frequency of the HPF is controlled depending on an output level of the HPF.
As shown in
The level detector 152 detects an output level (amplitude) of the HPF 151. The HPF controller 153 outputs a filter control signal for controlling the HPF 151 in such a manner that a cutoff frequency increases as an amplitude level rises. For example, the HPF controller 153 may include a coefficient table storing such values that the cutoff frequency linearly increases as the amplitude level rises. The HPF controller 153 may output the filter control signal that is extracted from the coefficient table corresponding to the input amplitude level.
According to the second embodiment, even when a frequency of a main component in a sound signal is close to or matches with a resonant frequency of a resonator and a level in the resonator rises, the HPF having the appropriately controlled cutoff frequency removes components of a low-frequency band. Therefore, a component that strongly resonates with a sound signal in a low-frequency band can be reduced while leaving a resonance sound in a high-frequency band.
A third embodiment according to the present invention will now be explained. The groups of resonators are respectively provided for the left and right channels in the first embodiment; however, a single resonator group is provided in the third embodiment.
As shown in
Further, the resonance sound adding device 122 includes a filter controller 43, a delay controller 44 and a gain controller 45.
In
In the third embodiment, as shown in
The delay controller 44 reads delay time data D which is to be supplied to the resonator group 133 from a coefficient table in a storage device 26. The filter controller 43 reads predetermined filter control data F from a filter control data table stored in the storage device 26 based on a damper level supplied from the CPU 12.
In the resonator group 133, each of resonators (five resonators are provided in the present embodiment) delays a signal based on the delay time data D supplied from the delay controller 44 and performs filtering processing on the signal in accordance with the filter control data F. The items of data output from the resonators are added at the adder 55, and the resultant data is output from the resonator group 133.
An output from the resonator group 133 is supplied to the LPF 135 and the HPF 136. The LPF 135 lets components of the resonance sound which are lower than a predetermined cutoff frequency pass therethrough. The HPF 136 lets component of the resonance sound which are higher than another predetermined cutoff frequency pass therethrough.
An output from the LPF 135 passes through the amplifier 38, and then is added to the sound signal data of the left channel in the adder 41 to be output. In addition, an output from the HPF 136 is added to the sound signal data of the right channel in the adder 42 to be output.
According to the third embodiment, by utilizing the LPF 135 and the HPF 136, the components of the resonance sound corresponding to lower frequencies are added to the sound signal of the left channel, and the components of the resonance sound corresponding to higher frequencies are added to the sound signal of the right channel. As a result, even one resonator group can provide a widely spreading resonance sound.
A fourth embodiment according to the present invention will now be explained. In the fourth embodiment, a coefficient table stored in a storage device 26 includes more items of delay time data than the number of resonators. The delay controller 44 reads out given items of delay time data from the coefficient table. The items of delay time data are supplied to the resonators.
In the fourth embodiment, items of delay time data to be selected from the coefficient table are changed based on tonality data. The tonality data indicates tonality of music included in demonstration data to be played in demonstration performance, or tonality input by a player operating an operation member in the group of operation members 16.
The coefficient table shown in
The coefficient selection table stores selection information to select or not to select items of information designating the items of the delay time data (e.g., DL1 to DL12 in
According to the coefficient selection table of the fourth embodiment, for each tonality, delay time data corresponding to resonant frequencies between the pitches of sounds corresponding to I, II, III, V, or VI and the pitches of adjacent keys are selected. In each tonality, sounds constituting a scale, especially I, II, III, V, and VI are frequently used. Therefore, selecting resonant frequencies which are close to some extent to the pitches of the above sounds makes it possible to generate a further appropriate resonance sound, though the selected frequencies are different from the pitches of the sounds.
Then, the CPU 12 acquires information designating delay time data from the coefficient selection table based on the acquired tonality data (step 1402), and informs the delay controller 44 in a resonance sound adding device 22 of the acquired information designating delay time data (step 1403).
The delay controller 44 reads predetermined items of the delay time data from the coefficient table stored in the storage device 26 based on the provided information designating the delay time data, and provide the items of the delay time data for resonators.
According to the fourth embodiment, the coefficient table includes more items of delay time data than the number of the resonators. The delay controller 44 reads different items of the delay time data corresponding to the number of the resonators from the coefficient table in accordance with the tonality data indicative of tonality of music to be played. Therefore, an appropriate resonance can be added in accordance with tonality of music to be performed.
Moreover, according to the fourth embodiment, the coefficient selection table stores information for designating items of delay time data stored in a coefficient table, for each tonality data. Accordingly, appropriate items of delay time data can be readily selected for each tonality without calculation.
The present invention can be modified in many ways within the scope of the present invention written in claims without being restricted to the foregoing embodiments and such modifications are also included in the scope of the invention.
For example, in the foregoing embodiments, an inverse number of an intermediate value between pitches of keys adjacent to each other or an intermediate value of inverse numbers of pitches of keys adjacent to each other is adopted as the delay time data, and such delay time data is stored in the coefficient table. However, the delay time data is not restricted thereto. A value that is ¼ higher than a pitch of a key may be adopted. In this case, the delay time data D (unit: ms) stored in the coefficient table has the following relationship with respect to a frequency (pitch) (unit: Hz) of a key designated by a “pitch_name”.
D=1/(Freq(pitch_name)*2̂(1/24))×1000
Provided the delay time data does not match with a cycle corresponding to the pitch of any key, any other delay time data, which corresponds to a cycle of a pitch other than a ¼ sound, may be adopted.
In the present embodiment, pitches of keys conform to equal temperament; however, the present invention can be likewise applied to a case where pitches of keys conform to other temperaments, e.g., stretch tuning wherein pitches of low sounds become further lower and pitches of high sounds become further higher, a Werckemeister temperament, or meantone system. In such a case, it is sufficient that the coefficient table of the storage device stores delay time data that does not match any cycles corresponding to pitches of keys. Alternatively, it is also enough that, when a player operates an operation member in the group of operation members 16 to select the temperament, the CPU 12 generates delay time data that does not match with any cycles corresponding to pitches of keys conforming to a selected temperament, and stores the generated data in the coefficient table.
In the first embodiment, the coefficient table may store more items of delay time data than the number of the resonators. The delay controller 44 may read as many different items of delay time data as the number of the resonators from the coefficient table. The delay controller 44 may randomly read items of the delay time data. Alternatively, the delay controller 44 may read items of the delay time data at fixed intervals, for example.
In the fourth embodiment, the CPU 12 makes reference to the coefficient selection table to inform the delay controller 44 of information designating items of the delay time data which are to be read by the delay controller 44. However, the CPU 12 may select delay time data corresponding to a cycle between a pitch constituting a scale of tonality data and a pitch adjacent thereto based on the tonality data without using the coefficient selection table.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-200373 | Aug 2007 | JP | national |
