JP3575083B2 - Music synthesizer - Google Patents

Description

【００３０】
なお、分配の方法としては、相乗平均として均等に配分しても良いし、いずれか一方を固定として他方を変化させても良い。また、厳密にいえば、ＬＰＦ６３、６６の特性を考慮してゲインを設定する必要があるので、これらＬＰＦ６３、６６の特性（係数）をゲインに反映するようにしても良い。
【００３１】
ここで、さらに乗算係数ｇについて考察する。いま、閉ループ回路６０における１巡あたりの遅延時間をｄ（ｓｅｃ）、１巡あたりの減衰量（ゲイン）をｇ、エンベロープの減衰率をｒ（ｄＢ／ｓｅｃ）とすると、閉ループ回路６０を巡回する信号振幅は、１秒あたりに１／ｄ（回）だけループゲインｇの乗算を受けることになる。したがって、次式が成立する。
【数２】

これにより、乗算係数ｇは、次の式が成立するように設定すればよい。
【数３】

【００３２】
なお、いうまでもないことだが、この式において、減衰率ｒは１秒あたりの減衰率を示すので、これを１サンプリング周期あたりの減衰率ｒ_０ に換算するには、サンプリング周波数をｆ_０ として次式のようにすれば良い。
【数４】

【００３３】
２：実施例の動作
次に、この実施例の動作について説明する。まず、演奏者等がギターなどの弦を弾いて、図８（ａ）のような楽音が発生したとすると、この楽音は、ピックアップ１０により電気信号に変換され、さらにＡ／Ｄ変換器１１によりディジタル信号に変換される。そして、このディジタルに変換された信号のエンベロープ波形（図８（ｂ）参照）とその立ち上がりの部とが、エンベロープ検出器１２により抽出・検出される。そして、このエンベロープ波形は、図８（ｃ）に示すように差分演算器１４により微分され、この微分波形にしたがって、ＭＩＤＩ変換器１５が１サンプリングクロックあたりのエンベロープ波形の減少値を示すコントロールチェンジＣＯＮＴ−ＣＧを出力する。この際、エンベロープ波形の増加値は、図５における符号反転器５１およびセレクタ５２により出力されないようになっている。一般にエンベロープの立ち上がり、すなわちアタック部は、ノートオンＮＯＴＥ−ＯＮに伴うオンベロシティＶＥＲＯＣＩＴＹにより定まるから、この部分の楽音合成については、オンベロシティＶＥＲＯＣＩＴＹを考慮するためである。
【００３４】
一方、エンベロープ検出器１２により検出されたエンベロープ波形の立ち上がり部によって、ノートオン検出器１６は発音開始のタイミングを検出する。また、Ａ／Ｄ変換器１１によりディジタルに変換された楽音信号は、ピッチ検出器１３によって、その音高が検出される。そしてＭＩＤＩ変換器１７は、発音開始のタイミングからノートオンＮＯＴＥ−ＯＮを、エンベロープ波形の最大値からオンベロシティＶＥＲＯＣＩＴＹを、検出された音高からキーコードＫＣをそれぞれ適切な形式に変換して出力する。このようにして、楽音合成に必要となる情報が音源回路１８に供給される。
【００３５】
次に、音源回路１８では、波形発生部７２が、波形ＷＡＶＥにしたがった波形信号を、キーコードＫＣにしたがった音高で、さらにオンベロシティＶＥＲＯＣＩＴＹにしたがった振幅で生成し、これを閉ループ回路６０における加算器６１、６２に供給する。これにより、波形信号は、励振信号として閉ループ回路６０を循環する。
一方、遅延時間設定部７３は、キーコードＫＣおよびベンド量ＢＥＮＤにしたがって閉ループ回路６０における遅延時間ＤＬＹを決定し、これとＬＰＦ６３、６６の遅延時間とを考慮しつつ、遅延回路６８の遅延時間ＤＬＹ１および遅延回路６５の遅延時間ＤＬＹ２を定め、これらを分配する。
また、ダンプ係数算出部７４は、コントロールチェンジＣＯＮＴ−ＣＧおよび遅延量ＤＬＹから、閉ループ回路６０における１巡あたりの減衰量を求め、この減衰量から乗算係数を求める。そして、この乗算係数ｇに基づき乗算係数ｇ_１、ｇ_２がそれぞれ分配器７５によって乗算器６７、６４に分配される。
【００３６】
このため、閉ループ回路６０に循環する励振信号は、発生楽音の音高および演奏者による操作子への操作量にしたがって１巡あたりの遅延時間が制御されるとともに、エンベロープの単位時間あたりの減少値および１巡あたりの遅延時間にしたがって１巡あたりの減衰量が制御されることとなる。したがって、この実施例によれば、波形発生部７２により生成した波形が、撥弦により実際に発生した楽音と同様に減衰し、さらに、この減衰には、演奏操作子の操作量も反映されるので、違和感なく自然に楽音合成をすることが可能となる。
【００３７】
（変形例）
なお、この実施例では次のような変形も可能である。
▲１▼ 閉ループ回路６０から出力される楽音信号のエンベロープ波形を検出するとともに、このエンベロープ波形と、ピックアップ１０により入力した楽音信号のエンベロープ波形とを比較して、この比較結果が同じになるように、閉ループ回路６０における１巡あたりの遅延時間および減衰量を制御するようにしても良い。すなわち、閉ループ回路６０から出力される楽音信号のエンベロープ波形をフィードバック制御しても良い。この構成によれば、合成された楽音を、実際に発音された楽音に、より近づけることが可能となる。
【００３８】
▲２▼ 上述した実施例では、閉ループ回路６０における１巡あたりの遅延時間および減衰量を、ギターを例にとり、撥弦による楽音のエンベロープ波形の時間的変化を用いて制御したが、本願はこれに限られない。例えば、鍵盤楽器における鍵の押圧力信号（アフタータッチ）をエンベロープ波形に代えて与え、この時間変化を検出して、閉ループ回路６０の各部を制御する構成としても良い。
【００３９】
▲３▼ 閉ループ回路６０における制御対象として、１巡あたりの遅延時間および減衰量とともに、フィルタの周波数特性を加えても良い。そして、例えば、エンベロープの絶対値レベルが大きいほど、あるいは変化（すなわち微分値、差分値）が大きいほど、フィルタの特性を開く（実施例でいえばＬＰＦ６６、６３のカットオフ周波数を上げる）構成としても良い。
【００４０】
▲４▼ また、上述した実施例では、ピックアップ１０によりギターの発音を入力する構成としたが、ギター以外の楽器でもあるいは音声でも勿論適用可能である。例えば、マイクロフォンによる入力や、他の音響信号発生装置・再生装置等からのライン入力によっても良い。その他、電子ドラム等の打撃センサの出力信号を入力しても良い。
【００４１】
▲５▼ また、実施例では、入力した楽音信号の時間変化を示すものとしてエンベロープ波形の差分値を用いたが、本願はこれに限られない。例えば、入力した信号の周波数成分や、周波数特性等の時間的変化を検出しても良い。また、ＭＩＤＩ規格のデータを用いずに、エンベロープの差分値を示すデータを音源回路１８に供給し、音源回路１８が、このデータから閉ループ回路６０での減衰率を計算する構成としても良い。
【００４２】
▲６▼ 上述した実施例では、入力した信号を解析する構成と音源回路とを一体化したものとしたが、セパレートしたものであっても良い。例えば、図１におけるエンベロープ検出器１２までをコントローラとして一体化し、その出力をＭＩＤＩ信号として送出する一方、差分演算器１４以降を音源装置として構成するなど考えられる。また、構成自体は、ハードウェアによるもののほか、マイクロコンピュータやＤＳＰ等によって構成して、かかる動作をソフトウェア的に行なっても良い。
【００４３】
【発明の効果】
以上説明したこの発明によれば、次のような効果がある。
生成した波形信号には、入力した発音信号あるいは振動信号と同様な減衰特性が付与されるので、演奏者は、この減衰特性を違和感なく制御することが可能となり、この際、減衰特性を個別に変化させる必要もない。特に、遅延回路の遅延時間と発音信号あるいは振動信号のレベルの時間変化とにしたがって乗算器の乗算係数が制御されるから、生成した波形は、演奏者による演奏操作にしたがった発音信号あるいは振動信号と同様に減衰する。したがって、演奏者固有の奏法による表現力を損なうことなく、楽音信号を合成することが可能となる。
【００４４】
発音信号あるいは振動信号の単位時間毎のレベルの差分値と遅延回路の遅延時間とを乗算することによって、閉ループ回路における１巡あたりの減衰量が制御されるので、発音信号あるいは振動信号のレベルの時間変化にしたがった減衰特性を付与するのが容易となる。
乗算器の乗算係数は、発音信号あるいは振動信号の検出結果とともに、演奏操作子への操作量にしたがっても制御されるので、演奏者の演奏法をより反映した楽音合成をすることが可能となる。
【図面の簡単な説明】
【図１】この発明による一実施例の構成を示すブロック図である。
【図２】同実施例におけるエンベロープ検出器の構成を示すブロック図である。
【図３】エンベロープ検出器における絶対値算出回路の構成を示すブロック図である。
【図４】同実施例における差分演算器の構成を示すブロック図である。
【図５】同実施例におけるＭＩＤＩ変換器の構成を示すブロック図である。
【図６】同実施例における音源回路の構成を示すブロック図である。
【図７】音源回路におけるダンプ係数算出部の構成を示すブロック図である。
【図８】同実施例の動作を説明するための図である。
【符号の説明】
１０……ピックアップ（入力手段）、１２……エンベロープ検出器（検出手段）、６０……閉ループ回路（減衰手段）、６４、６７……乗算器、６５、６８……遅延回路、７０……制御部（制御手段）、７２……波形発生部（楽音信号生成手段）[0001]
[Industrial applications]
The present invention relates to a tone synthesizer suitable for use in tone synthesis of a plucked string instrument.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a musical sound synthesizer that operates a model obtained by simulating a sounding mechanism of a natural musical instrument and thereby synthesizes a musical sound of the natural musical instrument. Among the musical tone synthesizers of this type, a low-pass filter and a multiplier that simulate the vibration loss of a string, and a delay circuit that simulates a propagation delay of the string are configured as a closed loop circuit to simulate a stringed instrument or the like. Are known.
On the other hand, conventionally, there is a guitar controller that converts a string vibration into, for example, a MIDI signal and outputs the converted signal. In addition, a sound source unit connected to the guitar controller generates a tone signal in accordance with the MIDI signal. Some guitar synthesizers do.
[0003]
There is also a synthesizer that combines such a guitar synthesizer with a tone synthesizer simulating a stringed instrument, and controls the output of a closed loop circuit in accordance with the envelope of the generated tone (see, for example, Japanese Patent Application Laid-Open No. 4-133099). .
[0004]
[Problems to be solved by the invention]
However, in this technique, the decay rate of a musical tone generated by a playing operation such as a plucked string is not limited to the decay in a broader sense, and the change rate of the amplitude envelope is different from the decay rate and the change rate of the closed loop circuit. For example, actually, the sound is generated by the vibration of the strings, and the signal in the closed loop circuit is attenuated first, or vice versa, despite the output of the guitar controller. In other words, in the above technique, the closed loop circuit does not simulate the actual vibration loss and propagation delay of the string. For this reason, there is a problem that the synthesized musical tones give the player an uncomfortable feeling.
[0005]
Further, in the above technique, the player himself cannot change the characteristics of the closed loop circuit. If a configuration for directly changing this is considered, another operator (such as a pedal) for changing the characteristics of the closed loop circuit is required in addition to the performance operator on the guitar. In the performance in this case, there is a problem that the burden on the guitar player is significantly increased, and the expressive power of the player himself is impaired.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to be able to synthesize a tone signal without impairing the expressiveness of a player's unique playing style and without giving a sense of incongruity. To provide a simple tone synthesis device.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides an input means for inputting a sound signal or a vibration signal according to a performance operation by a player, and a time change of the level of the sound signal or the vibration signal input by the input means.Minute, A waveform generating means for generating a waveform signal in accordance with a performance operation performed by a player or supplied performance information, and a closed loop including a delay circuit and a multiplier. A delay circuit for controlling the delay time of the delay circuit in accordance with a pitch of a musical tone to be generated, and a time change of the delay time and a level of a sound signal or a vibration signal detected by the detection means.MinuteControl means for controlling the multiplication coefficient of the multiplier in accordance with the above.
[0008]
According to the invention described in claim 2, in the invention described in claim 1,The detecting means calculates a difference value per unit time for a level of a sound signal or a vibration signal input by the input means, and the control means calculates the difference value and a delay time of the delay circuit. Calculate the multiplication coefficient of the multiplier by multiplyingIt is characterized by:
According to the invention described in claim 3, according to claim 1ofIn the present invention, there is provided means for detecting an operation amount of the performance operator by the player, and the control means is configured to detect an operation amount of the performance operator according toMultiplication coefficient of the multiplierIs controlled.
[0009]
[Action]
According to the first aspect of the present invention, the sound signal or the vibration signal according to the performance operation by the player is input by the input means, and the detection means changes the level of the sound signal or the vibration signal with time.MinuteIs detected. The waveform generating means generates a waveform signal according to a performance operation by the player or the supplied performance information. This waveform signal is circulated through a closed loop including a delay circuit and a multiplier. At this time, the delay time of the delay circuit is controlled by the pitch of a musical tone to be generated, and the multiplier coefficient of the multiplier is determined by the delay time and the sound generation. Time change of signal or vibration signal levelMinuteAnd is controlled by
[0010]
According to the invention described in claim 2,The detection unit calculates a difference value per unit time with respect to the level of the sound signal or the vibration signal input by the input unit. The multiplier coefficient of the multiplier is calculated by multiplying the difference value by the delay time of the delay circuit., Per round in a closed loop circuitAttenuationIs controlled.
According to the third aspect of the present invention, the detection result based on the sound signal or the vibration signal is used together with the operation amount of the performance operator.Multiplier multiplierIs controlled.
[0011]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1: Overall configuration of the embodiment
FIG. 1 is a block diagram showing the overall configuration of this embodiment. In this embodiment, a musical sound repelled by a music repelling device is input, and the musical sound signal is analyzed to obtain information on a time change of an envelope and the like, and from this information, a musical sound signal generated by a sound source is circulated to a closed loop circuit. And controls the closed loop circuit.
[0012]
In this figure, reference numeral 11 denotes an A / D converter, which converts a tone signal captured by the pickup 10 into a digital signal. The pickup 10 in this embodiment is typically attached to a plucked string instrument, for example, a guitar, and takes in a musical sound by a plucked string, and is provided corresponding to each string. The following blocks may be considered to be provided in parallel corresponding to the pickup, or may be considered to be processed by time division multiplexing.
[0013]
Next, reference numeral 12 denotes an envelope detector, which extracts an envelope waveform of the tone signal converted into digital by the A / D converter 11. The detailed configuration will be described later. On the other hand, reference numeral 13 denotes a pitch detector, which detects the pitch, that is, the frequency of the tone signal digitally converted by the A / D converter 11, that is, the musical pitch. Note that the pitch detector 13 is configured by a known technique generally used in the field of voice analysis and the like, for example, a technique such as a period measurement method and an autocorrelation function method.
[0014]
Reference numeral 14 denotes a difference calculator which obtains a difference value of the envelope waveform extracted by the envelope detector 12 for each unit time, that is, for each sampling period of the A / D converter 11. Reference numeral 15 denotes a MIDI converter, which obtains a control change CONT-CG corresponding to the difference value obtained by the difference calculator 14 from a conversion table in which the correspondence is stored in advance and outputs the MIDI change as a MIDI signal. Here, the control change CONT-CG is generally information for controlling an effect function.
[0015]
On the other hand, reference numeral 16 denotes a note-on detector, which detects an attack (rising) portion of the envelope waveform extracted by the envelope detector 12 and detects the timing of sound generation and its magnitude. Next, reference numeral 17 denotes a MIDI converter, which converts a pitch detected by the pitch detector 13 and a note-on NOTE-ON corresponding to a sounding timing detected by the note-on detector 16 and its magnitude. The correspondence is obtained from a conversion table storing the correspondence in advance and is output as a MIDI signal. Here, the note-on NOTE-ON is information for instructing the start of sound generation, and is usually accompanied by a key code KC indicating a pitch of sound generation and an on-velocity VEROCITY indicating a magnitude of sound generation.
[0016]
Reference numeral 18 denotes a tone generator circuit, which generates a tone signal based on information supplied by each unit and circulates the tone signal through a closed loop circuit including a delay circuit, a multiplier, a filter, and the like, as described later. By controlling the characteristics of the closed loop circuit based on this, the generated tone signal is given an attenuation characteristic and output. In this embodiment, since the target is a guitar sound, an attenuation characteristic is provided. However, it is also possible to provide a characteristic such that the amplitude envelope is sharply increased.
[0017]
Next, details of each unit in FIG. 1 will be described.
1-1: Envelope detector
First, the configuration of the envelope detector 12 will be described. FIG. 2 is a block diagram showing a configuration of the envelope detector 12. As shown in FIG. In this figure, an absolute value calculation circuit 20 calculates an absolute value of a tone signal digitally converted by the A / D converter 11 (see FIG. 1), as described later. The adder 21 subtracts the output of the delay circuit 22 from the output of the absolute value calculation circuit 20 to obtain a difference signal. The sign detection circuit 23 detects the sign based on the most significant bit MSB of the difference signal, and switches the switch 24 in accordance with the detection result. If the sign of the difference signal is positive, the sign is set to the terminal 24a. , If the sign is negative, it is set to the terminal 24b side. The terminal 24a and the terminal 24b are supplied with an attack rate (rise coefficient) and a decay rate (attenuation coefficient) of the envelope from a circuit (not shown), respectively. The difference signal is supplied as a multiplication coefficient and multiplied. The adder 26 adds the result of the multiplication by the multiplier 25 and the result of the delay by the delay circuit 27. The addition result is output from the envelope detector 12, while being delayed by one sampling clock by the delay circuit 22 and input to the adders 21 and 26.
[0018]
1-1-1: Absolute value calculation circuit
Here, the absolute value calculation circuit 20 will be described. FIG. 3 is a block diagram showing the configuration. Note that the output of the A / D converter 11 (see FIG. 1) is n bits and is supplied in two's complement notation. As shown in the figure, at the output of the A / D converter 11, the exclusive OR of the most significant bit MSB indicating the positive / negative sign and each bit from the upper bit 2SB to the least significant bit LSB is determined by an EX-OR gate. 31₂~ 31_n, And is supplied to the half adder 32 as an input to be added. On the other hand, the most significant bit MSB is supplied to a Cin (carry) input terminal of the half adder 32.
[0019]
Accordingly, when the output of the A / D converter 11 is positive, the half adder 32 outputs 2SB to LSB indicating the actual value as it is, while the output of the A / D converter 11 is When the value is negative, a value obtained by adding (1) (carrying) "1" to the inverted value of each bit of 2SB to LSB is output. That is, the absolute value of the output from the A / D converter 11 is output. Since the output of the half adder 32 is (n-1) bits as it is, a bit of "0" indicating positive is added as the most significant bit MSB, and again as n bits, the addition in FIG. To be supplied to the vessel 21.
[0020]
Returning to FIG. In the envelope detector 12, first, the absolute value of the output of the A / D converter 11 obtained by the absolute value calculation circuit 20 is added to the adder 21 by the output delayed by one sampling clock by the delay circuit 22. Is subtracted by Therefore, the output of the adder 21 is a difference signal indicating how much the signal has increased or decreased since one sampling clock before. If this difference signal is positive, that is, if the output of the A / D converter 11 is increasing (attack), this difference signal is multiplied by the attack rate, while if the difference signal is negative, that is, If the output of the A / D converter 11 is decreasing (decay), the difference signal is multiplied by the decay rate. The result of multiplying the difference signal by a coefficient corresponding to the positive / negative of the difference signal and the output one sampling clock before are added by the adder 26, so that the envelope of the output of the A / D converter 10 is eventually output. Will be different. At this time, the shape of the envelope waveform can be set by adjusting the attack rate or the decay rate. For example, when the input signal is attacking, the response is made faster by decreasing the attack rate, while during decay, the response is delayed by increasing the decay rate, setting the envelope waveform to the so-called "first attack slow release" characteristic And so on.
[0021]
1-2: Difference calculator
Next, the difference calculator 14 in FIG. 1 will be described. FIG. 4 is a block diagram showing the configuration. As shown in this figure, the difference calculator 14 is composed of a linear / log conversion table 40 located at the preceding stage and a differentiator 41 located at the succeeding stage. The linear / log conversion table 40 stores a logarithmic value for an input value in advance, reads out a logarithmic value corresponding to the input value, and outputs the logarithmic value. Hereinafter, the linear / log conversion table 40 is provided to handle the difference in dB (decibel) notation. . The differentiator 41 further includes an adder 42 and a delay circuit 43 having a delay time of one sampling clock. The adder 42 subtracts the output of the delay circuit 43, that is, the output value of the linear / log conversion table 40 one sampling clock before, from the output value of the linear / log conversion table 40. The difference value of is output.
[0022]
1-3: MIDI converter (control change)
Next, the MIDI converter 15 in FIG. 1 will be described. FIG. 5 is a block diagram showing the detailed configuration. As shown in this figure, the difference value of the envelope output by the difference calculator 14 is first inverted in sign by a sign inverter 51 and supplied to the input terminal A of the selector 52. On the other hand, the input terminal B of the selector 52 is supplied with data of all bits zero. The selection of the input terminal in the selector 52 is performed by the MSB indicating the sign of the difference value after the inversion. When the MSB is zero, the input terminal A is selected. That is, when the difference value after the inversion is negative, the input terminal B is selected and zero data is output. In this embodiment, the control according to the attenuation of the envelope (the difference value becomes negative at this time, but becomes positive by the sign inverter 51) is performed, and the difference value when the envelope is increased is cut. To do that.
[0023]
In any case, the output of the selector 52 is supplied to the MIDI code conversion table 53 as data indicating a value of zero or more. The MIDI conversion table 53 is a table for converting a value indicating the attenuation rate of the envelope into a control change CONT-CG according to the MIDI standard. Here, the control change is generally used for controlling the effect function in the performance as described above, but in the present application, the control change is used for controlling the attenuation characteristic of the tone generator circuit 18 described below. Can be
[0024]
1-4: tone generator circuit
The configuration of the tone generator 18 in FIG. 1 will be described. FIG. 6 is a block diagram showing the detailed configuration. As shown in this figure, the sound source circuit 18 includes a control change CONT-CG by the MIDI converter 15, a note-on NOTE-ON by the MIDI converter 17, a bend amount BEND set by a not-shown operator, and a tone color. Is supplied. Here, the bend amount BEND is data indicating the effect amount of the effect in the guitar performance, and is in accordance with the amount by which the player operates an operation element provided on a musical instrument such as a pedal. The sound source circuit 18 is roughly divided into a closed loop circuit 60 mainly composed of a delay circuit, a low-pass filter (LPF) and the like, and a control unit 70 for controlling each part of the closed loop circuit 60 according to supplied information. You.
[0025]
The note-on control section 71 extracts the key code KC and velocity VEROCITY associated therewith from the note-on NOTE-ON and supplies them to the waveform generation section 72. The waveform generating unit 72 is a kind of waveform memory that stores a plurality of timbres in advance corresponding to pitches, reads out a waveform corresponding to the waveform WAVE together with information from the note-on control unit 71, and uses this as an excitation signal. It is supplied to the closed loop circuit 60. The waveform generator 72 is not limited to the waveform memory, and may use a modulation method such as FM or AM, or any other waveform generation method.
[0026]
The waveform generated by the waveform generator 72 is supplied to adders 61 and 62. The waveform supplied to the adder 61 is added to the output of the delay circuit 68, filtered by the LPF 63, and multiplied by the multiplier 64 by the multiplication coefficient g.₂  , And further delayed by a time corresponding to the delay time DLY2 by the delay circuit 65, and added by the adder 62 to the waveform of the waveform generator 72. Similarly, the waveform supplied to the adder 62 is also added to the output of the delay circuit 65, filtered by the LPF 66, and multiplied by the multiplier 67 by the multiplication coefficient g.₁  , And delayed by a time corresponding to the delay time DLY1 by the delay circuit 68, and added by the adder 61 to the waveform of the waveform generator 72. In this way, the waveform generated by the waveform generator 72 circulates through the closed loop circuit 60. Both outputs of the delay circuits 65 and 68 are taken out, and both are added by the adder 69. Is supplied to the outside as an output.
[0027]
The closed loop circuit 60 simulates the damping characteristic of a plucked string instrument such as a guitar. The manner in which each part simulates the vibration of a string is described in, for example, JP-A-3-58096. It is described in the gazette.
[0028]
On the other hand, the delay times DLY1 and DLY2 in the delay circuits 65 and 68 are set by the delay time setting unit 73. The delay time setting unit 73 sets the delay times DLY1 and DLY2 in consideration of the bend amount BEND and the key code KC associated with the note-on NOTE-ON, for example, using a table in which the correspondence is determined in advance. Here, the key code KC indicating the pitch is referred to in the setting of the delay times DLY1 and DLY2. Generally, the vibration decay time of the string differs depending on the frequency (that is, the pitch). This is to simulate. As for the delay times DLY1 and DLY2 set by the delay time setting unit 73, the total delay time per round in the closed loop circuit 60 is DLY, and each delay time in the LPFs 63 and 66 is α₁, Α₂Then
DLY = DLY1 + DLY2 + α₁+ Α₂
There is a relationship. That is, the delay time setting unit 73 determines the delay times DLY1 and DLY2 in consideration of the delay times in the LPFs 63 and 66. Regarding how to distribute, one of them may be fixed or the arithmetic mean may be used.
[0029]
Further, the multiplication coefficient g in the multipliers 67 and 64₁, G₂Is set by the dump coefficient calculation unit 74. As shown in FIG. 7, the dump coefficient calculation unit 74 multiplies the delay time DLY by the delay time setting unit 73 by the control change CONT-CG by the MIDI converter 15, and multiplies the multiplication result. And a dump coefficient conversion table 82 for converting into a coefficient g.
Here, the control change CONT-CG is a difference value of the envelope, which is a value per sampling clock. Therefore, the product of the control time CONT-CG and the delay time DLY indicates an attenuation amount per round in the closed loop circuit 60. Will be. This attenuation amount is converted into a multiplication coefficient g by the dump coefficient conversion table 82. Returning to FIG. 6 again, the distributor 75 sets the multiplication coefficient g satisfying the following equation.₁, G₂Is distributed to multipliers 64 and 67, respectively.
(Equation 1)

[0030]
As a method of distribution, the distribution may be equally performed as a geometric mean, or one of them may be fixed and the other may be changed. Strictly speaking, since it is necessary to set the gain in consideration of the characteristics of the LPFs 63 and 66, the characteristics (coefficients) of the LPFs 63 and 66 may be reflected in the gain.
[0031]
Here, the multiplication coefficient g will be further considered. Now, assuming that the delay time per round in the closed loop circuit 60 is d (sec), the attenuation amount (gain) per round is g, and the attenuation rate of the envelope is r (dB / sec), the closed loop circuit 60 is circulated. The signal amplitude is multiplied by the loop gain g 1 / d (times) per second. Therefore, the following equation is established.
(Equation 2)

Thus, the multiplication coefficient g may be set so that the following equation is satisfied.
(Equation 3)

[0032]
Needless to say, in this equation, the decay rate r indicates the decay rate per second.₀  To convert the sampling frequency to f₀  The following equation may be used.
(Equation 4)

[0033]
2: Operation of the embodiment
Next, the operation of this embodiment will be described. First, if a player or the like plays a string of a guitar or the like and a musical tone as shown in FIG. 8A is generated, the musical tone is converted into an electric signal by the pickup 10 and further converted by the A / D converter 11. It is converted to a digital signal. Then, the envelope waveform (see FIG. 8B) of the digitally converted signal and the rising portion thereof are extracted and detected by the envelope detector 12. Then, the envelope waveform is differentiated by the difference calculator 14 as shown in FIG. 8C, and according to the differentiated waveform, the MIDI converter 15 performs a control change CONT indicating a decreasing value of the envelope waveform per one sampling clock. -Output CG. At this time, the increase value of the envelope waveform is not output by the sign inverter 51 and the selector 52 in FIG. In general, the rise of the envelope, that is, the attack portion is determined by the on-velocity VEROCITY associated with the note-on NOTE-ON. Therefore, the tone synthesis in this portion is performed in consideration of the on-velocity VEROCITY.
[0034]
On the other hand, the note-on detector 16 detects the start timing of sound generation based on the rising portion of the envelope waveform detected by the envelope detector 12. The pitch of the tone signal converted into digital by the A / D converter 11 is detected by the pitch detector 13. Then, the MIDI converter 17 converts the note-on note-on from the timing of the sound generation start, the on-velocity VEROITY from the maximum value of the envelope waveform, and the key code KC from the detected pitch to an appropriate format, and outputs them. . In this way, information necessary for tone synthesis is supplied to the tone generator 18.
[0035]
Next, in the tone generator 18, the waveform generator 72 generates a waveform signal according to the waveform WAVE with a pitch according to the key code KC and an amplitude according to the on-velocity VEROCITY, and generates the waveform signal according to the closed loop circuit 60. Are supplied to the adders 61 and 62 in. Thus, the waveform signal circulates through the closed loop circuit 60 as an excitation signal.
On the other hand, the delay time setting unit 73 determines the delay time DLY in the closed loop circuit 60 according to the key code KC and the bend amount BEND, and considers the delay time DLY1 of the delay circuit 68 while considering this and the delay time of the LPFs 63 and 66. And the delay time DLY2 of the delay circuit 65 is determined and distributed.
Further, the dump coefficient calculation unit 74 obtains the attenuation amount per round in the closed loop circuit 60 from the control change CONT-CG and the delay amount DLY, and obtains a multiplication coefficient from this attenuation amount. Then, based on the multiplication coefficient g, the multiplication coefficient g₁, G₂Are distributed to the multipliers 67 and 64 by the distributor 75, respectively.
[0036]
Therefore, the excitation signal circulating through the closed loop circuit 60 controls the delay time per cycle according to the pitch of the generated musical tone and the amount of operation performed by the player on the operator, and also decreases the envelope value per unit time. The amount of attenuation per cycle is controlled according to the delay time per cycle. Therefore, according to this embodiment, the waveform generated by the waveform generating section 72 is attenuated in the same manner as the musical tone actually generated by the plucking, and the amount of operation of the performance operator is also reflected in this attenuation. Therefore, it is possible to naturally synthesize a musical tone without a sense of incongruity.
[0037]
(Modification)
In this embodiment, the following modifications are possible.
(1) The envelope waveform of the tone signal output from the closed loop circuit 60 is detected, and the envelope waveform is compared with the envelope waveform of the tone signal input by the pickup 10 so that the comparison result is the same. Alternatively, the delay time and the amount of attenuation per round in the closed loop circuit 60 may be controlled. That is, the envelope waveform of the tone signal output from the closed loop circuit 60 may be feedback controlled. According to this configuration, it is possible to bring the synthesized musical tone closer to the actually generated musical tone.
[0038]
{Circle around (2)} In the above-described embodiment, the delay time per loop and the amount of attenuation in the closed loop circuit 60 are controlled using the temporal change of the envelope waveform of the musical sound due to the plucking of a guitar as an example. Not limited to For example, a configuration may be adopted in which a key pressing force signal (after touch) of a keyboard instrument is given instead of an envelope waveform, and this time change is detected to control each unit of the closed loop circuit 60.
[0039]
{Circle around (3)} As a control target in the closed loop circuit 60, the frequency characteristic of the filter may be added together with the delay time and the attenuation amount per round. For example, the filter characteristic is opened (the cutoff frequency of the LPFs 66 and 63 is increased in the embodiment) as the absolute value level of the envelope is larger or the change (that is, the differential value or the difference value) is larger. Is also good.
[0040]
{Circle around (4)} In the above-described embodiment, the configuration is such that the sound of the guitar is input by the pickup 10. However, it is needless to say that a musical instrument other than the guitar or a voice can be applied. For example, input by a microphone or line input from another acoustic signal generating device / reproducing device may be used. In addition, an output signal of a hit sensor such as an electronic drum may be input.
[0041]
{Circle around (5)} In the embodiment, the difference value of the envelope waveform is used to indicate the time change of the input tone signal, but the present invention is not limited to this. For example, a time component such as a frequency component of an input signal or a frequency characteristic may be detected. Alternatively, data indicating the difference value of the envelope may be supplied to the tone generator 18 without using the MIDI standard data, and the tone generator 18 may calculate the attenuation rate in the closed loop circuit 60 from the data.
[0042]
{Circle around (6)} In the above-described embodiment, the configuration for analyzing the input signal and the tone generator circuit are integrated, but may be separated. For example, it is conceivable that the components up to the envelope detector 12 in FIG. 1 are integrated as a controller and the output thereof is transmitted as a MIDI signal, while the difference calculator 14 and subsequent components are configured as a sound source device. The configuration itself may be configured by a microcomputer, a DSP, or the like, instead of hardware, and the operation may be performed by software.
[0043]
【The invention's effect】
According to the present invention described above, the following effects can be obtained.
Since the generated waveform signal has the same attenuation characteristics as the input sound signal or vibration signal, the performerThis damping characteristicCan be controlled without discomfort, and in this case, there is no need to individually change the attenuation characteristics.In particular, since the multiplier coefficient of the multiplier is controlled according to the delay time of the delay circuit and the time change of the level of the sound signal or vibration signal, the generated waveform is generated by the sound signal or vibration signal according to the performance operation by the player. Attenuates in the same way as.Therefore, it is possible to synthesize a tone signal without deteriorating the expressive power of the player's unique playing style..
[0044]
Sound or vibration signalMultiply the level difference value per unit time by the delay time of the delay circuitBy this, per round in a closed loop circuitAttenuationIs controlled, so that the sound signal or vibration signalOf levelEasier to provide damping characteristics over time.
Multiplier multiplierIs controlled according to the operation amount of the performance operator together with the detection result of the sound signal or the vibration signal.How to playIt is possible to synthesize musical sounds that reflect more.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment according to the present invention.
FIG. 2 is a block diagram showing a configuration of an envelope detector in the embodiment.
FIG. 3 is a block diagram illustrating a configuration of an absolute value calculation circuit in the envelope detector.
FIG. 4 is a block diagram illustrating a configuration of a difference calculator according to the embodiment.
FIG. 5 is a block diagram showing a configuration of a MIDI converter in the embodiment.
FIG. 6 is a block diagram showing a configuration of a tone generator circuit in the embodiment.
FIG. 7 is a block diagram illustrating a configuration of a dump coefficient calculation unit in the tone generator circuit.
FIG. 8 is a diagram for explaining the operation of the embodiment.
[Explanation of symbols]
10 pickup (input means), 12 envelope detector (detection means), 60 closed loop circuit (attenuation means), 64, 67 multiplier, 65, 68 delay circuit, 70 control Section (control means), 72... Waveform generating section (musical sound signal generating means)

Claims (3)

Input means for inputting a sound signal or a vibration signal according to a performance operation by a player;
Detecting means for detecting a time variation of the level of the input sound signal or vibration signal by said input means,
Waveform generating means for generating a waveform signal in accordance with a performance operation performed by a player or supplied performance information;
A closed loop circuit having a closed loop including a delay circuit and a multiplier, and causing the closed loop to circulate the waveform signal;
Controls the delay time of the delay circuit in response to the pitch of the to be sounded musical tone, the multiplier in accordance with the time variation of the level of the detected sound signal or vibration signal by the delay time and the detection means And a control means for controlling a multiplication coefficient of the musical tone. The detecting means is for calculating a difference value per unit time for the level of the sound signal or vibration signal input by the input means,
2. The musical sound synthesizer according to claim 1, wherein the control unit calculates a multiplication coefficient of the multiplier by multiplying the difference value by a delay time of the delay circuit. Means for detecting the operation amount of the performance operator by the player,
2. The musical tone synthesizer according to claim 1, wherein said control means controls a multiplication coefficient of said multiplier according to an operation amount of a performance operator.

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