Musical tone synthesizing apparatus

• US 5,519,167 A
• Filed: 08/04/1994
• Issued: 05/21/1996
• Est. Priority Date: 08/09/1993
• Status: Expired due to Term

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Kitayama, Toru, Masuda, Hideyuki, Kunimoto, Toshifumi
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): DONELS, JEFFREY
• Application Number:
  US08/285,964
• Time in Patent Office: 656 Days
• Field of Search: 84/627, 84/631, 84/630, 84/663, 84/661, 84/625
• US Class Current: 84/661
• CPC Class Codes: G10H 1/125 using a digital filter
• CPC Class Codes: G10H 2250/461 Gensound wind instruments, i.e. generating or synthesising the sound of a wind instrument, controlling specific features of said sound spint wind instruments G10H2230/155; mouth or breath sensors G10H2220/361; natural aerodynamic noise synthesis, e.g. wind G10H2250/431
• CPC Class Codes: G10H 2250/521 Closed loop models therefor, e.g. with filter and delay line
• CPC Class Codes: G10H 5/007 Real-time simulation of G10B, G10C, G10D-type instruments using recursive or non-linear techniques, e.g. waveguide networks, recursive algorithms

Abstract

In a musical tone synthesizing apparatus, employed by an electronic musical instrument, an excitation signal circulates through a waveguide to form a musical tone signal corresponding to a synthesized musical tone. The waveguide is configured by a loop circuit containing an adder, a delay circuit, a filter and an amplifier. A delay time used for the delay circuit is determined in response to a tone pitch of a musical tone to be produced, while a filter coefficient used for the filter is determined in response to a tone color of the musical tone to be produced. A multiplication coefficient used for the multiplier is generated in accordance with one of the tone pitch and delay time; or the multiplication coefficient is computed on the basis of the tone pitch and a decay rate which is set by a performer. In addition, a different multiplication coefficient can be generated in response to a state of an envelope waveform of the musical tone to be produced. For example, the multiplication coefficient to be generated for an attack portion of the envelope waveform can be differed from the multiplication coefficient to be generated for a decay portion of the envelope waveform. By finely controlling a loop gain of the waveguide corresponding to the multiplication coefficient, a fine control can be performed for the synthesis of the musical tones.

Claims

1. A musical tone synthesizing apparatus which synthesizes a musical tone signal by circulating an excitation signal, corresponding to a production of a musical tone, through a loop circuit containing a multiplier and a delay means, comprising:

delay-time control means for controlling a delay time of said delay means in accordance with a tone pitch of a musical tone to be produced; and

multiplication-coefficient generating means, which is activated responsive to start and end timings to produce the musical tone, for generating a multiplication coefficient for said multiplier on the basis of the delay time and the tone pitch of the musical tone to be produced.

2. A musical tone synthesizing apparatus which synthesizes a musical tone signal by circulating an excitation signal through a waveguide at least containing a delay circuit and a multiplier, comprising:

delay-time control means for controlling a delay time of said delay circuit in accordance with a tone pitch of a musical tone to be produced;

first coefficient generating means for generating a first coefficient on the basis of the tone pitch, said first coefficient being used by said multiplier in response to an attack portion of an envelope waveform of the musical tone to be produced;

second coefficient generating means for generating a second coefficient on the basis of one of the tone pitch and the delay time, said second coefficient being used by said multiplier in response to a decay portion of the envelope waveform of the musical tone to be produced; and

coefficient selecting means for selecting one of said first and second coefficients as a multiplication coefficient of said multiplier in accordance with a state of the envelope waveform of the musical tone to be produced.

3. A musical tone synthesizing apparatus according to claim 2 further comprising:

filter-coefficient generating means for generating a filter coefficient for a filter, contained in said waveguide, in response to a tone color of the musical tone to be produced.

4. A musical tone synthesizing apparatus comprising:

excitation-waveform generating means for generating an excitation waveform;

variable delay means for delaying said excitation waveform by a desired amount of delay;

variable amplifier means for attenuating an output waveform of said variable delay means by a desired amount of attenuation;

adder means for adding an output of said variable amplifier means to said excitation waveform, wherein said variable delay means, said variable amplifier means and said adder means are configured together to form a feedback loop;

first setting means for setting the desired amount of delay;

second setting means for setting an attenuation characteristic for a musical tone signal to be outputted from said variable delay means; and

third setting means for setting the desired amount of attenuation in response to the desired amount of delay and the attenuation characteristic.

5. A musical tone synthesizing apparatus which synthesizes a musical tone signal by circulating an excitation signal through a loop circuit containing an adder, a filter, a delay circuit and a multiplier, comprising:

delay-time determining means for determining a delay time for the delay circuit in accordance with a tone pitch of a musical tone to be produced;

filter-coefficient determining means for determining a filter coefficient for the filter in accordance with a tone color of the musical tone to be produced; and

loop-gain computing means for computing a loop gain on the basis of a decay rate and the tone pitch of the musical tone to be produced, said loop gain being used as a multiplication coefficient of the multiplier.

6. A musical tone synthesizing apparatus according to claim 5 wherein said loop-gain computing means computes the loop gain `a`, on the basis of the decay rate `d` and the tone pitch `p`, in accordance with a following equation:

space="preserve" listing-type="equation">a=1-(1-d)/p.