Kabushiki Kaisha Kawai Gakki Seisakusho

Kawai Musical Inst. Mfg. Co., Ltd.

Kawai Musical Instruments Manufacturing Co., Ltd.

Taichi Kosugi

Takashi Suzuki

Tsutomu Saito

Yutaka Washiyama

An electronic musical instrument has an effect adder circuit for adding sound effect which is controlled by coefficients for filtering operations and amplitude control. The instrument also has a smoothing circuit for smoothly changing a coefficient to a target value by interpolating between the coefficient current value and the coefficient target value to be updated. Smoothing is implemented by repeatedly adding or subtracting a given value to or from the coefficient current value until it reaches the coefficient target value. The precision of the smoothing coefficient depends on the word length of the coefficient current value so that the word length of the coefficient target value can be smaller than that of the coefficient current value. The effect adder circuit and smoothing circuit are independently provided to operate in parallel.

Effect adder circuit with a coefficient smoothing circuit for an

Digital waveform data stored in a waveform memory is read out in response to the ON/OFF operations of key switches such as a keyboard of an electronic musical instrument. The waveform data is passed through a low-pass filter, then subjected to amplitude envelope processing such as attack, decay, release, and the like. The processed waveform data is D/A-converted to output it as a tone signal. A look-up table that stores resonant frequency data and resonance sharpness data (quality factor) of a filter in correspondence with the touch (operation strength or key-ON velocity) of the switch operation at, e.g., the keyboard is used. The resonant frequency and resonance sharpness data are read out from the table in correspondence with the touch data of the keyboard operation to control filter characteristics such as a cutoff frequency, roll-off or slope, and the like, by coefficient data to the filter.

Electronic musical instrument with a variable coefficients digital

Waveform memory (12) stores a plurality of consecutive waveform sampling value data at a single address. Even when some waveform sampling values are skipped in a process of reproducing a musical tone of a frequency higher than a pitch inherent to a waveform prestored in the memory (12), all of the consecutive sampling values are sequentially read out and stored in temporary storage means (40.about.46) so that the interpolation calculation is accurately performed using the consecutive sampling values.

Electronic musical instrument and method for storing a plurality of

A digital filter device, for an electronic musical instrument, comprises: filter coefficient generation means for generating a set of filter coefficients in consonance with a designated resonance frequency and Q; and filter operation means for performing an operation for an IIR digital filter, relative to an input tone wave, by using the filter coefficient, which is generated by the filter coefficient generation means, with the filter coefficient generation means including trigonometric function output means, for outputting a trigonometric function value that is consonant with the resonance frequency, and filter coefficient calculation means, for calculating a plurality of filter coefficients based on the Q and the trigonometric function value that is generated by the trigonometric function output means, and with the filter coefficient calculation means having segment approximation means for performing, within a range of x.gtoreq.0, segment approximation of a function f(x)=x/(1+x), or f(x)=1/(1+x), and for outputting the filter coefficients.

Digital filter device for electronic musical instruments

In an electronic musical instrument which generates musical tone signals based on playing information input from a key switch circuit 10, a key scan circuit 11 includes a decode circuit 22 to which the current status information and the previous status information read out from a scan data memory 21 are input, and if status information which cannot be processed is input, the decode circuit 22 converts it to status information which can be processed, and if there is no empty space in an output data buffer 24, the decode circuit 22 detects no status change. Such construction allows malfunction to be prevented with a simple construction.

Electronic musical instrument

In a musical tone generator 6 having a waveform memory 8, and an interpolatory calculation circuit 21 for performing an interpolatory calculation on the basis of the plurality of sample values, there are provided a second waveform memory in which the sample values necessary for the interpolatory calculation at the beginning of tone generating are stored, and a transfer circuit for reading out the sample values from the second waveform memory at the beginning of tone generating, and writing them into the interpolation means.

Musical tone generator

An envelope generator for an electronic musical instrument, in which a current value of the envelope approaching asymptotically to a target level, using a subtracter means for subtracting from data representing the target level in a floating point representation, data representing the difference between the target level and the current value in a floating point representation with deeming these data as fixed point data each having a decimal point between an exponent part and a fractional part, and a comparator for comparing the output of the subtracter means with a predetermined constant, and for judging that an envelope phase transfer condition is met if the output of the subtracter is greater than the constant. The envelope generator can achieve a phase transfer control function substantially similar to prior art envelope generators by a small amount of hardware.

Envelope generator for electronic musical instrument

A channel assigning system which effects an assignment of a channel other than a predetermined number channels which are preferentially assigned to any part of a piece of music, to a part thereof. To thus ensure an efficient use of the channels. Further, the predetermined number of channels to be assigned to any part of the piece of music can be ensured by assigning channels, other than the channels to be secured to newly performed musical tones.

Channel assigning system for use in an electronic musical instrument

A key touch detector, for an electronic musical instrument, that detects key touch states, comprises: a first switch to be closed at a first key displacement position disposed along the line of travel of a depressed key; a second switch to be closed at a second key displacement position disposed along the line of travel of the depressed key; a key depression detector for detecting the closure of the first switch and the closure of the second switch; a touch data computer for computing touch data for the depressed key during a period that begins following the closure of the first switch and ends with the closure of the second switch; and delay circuitry for deferring initiation of touch data computation by the touch data computer until a predetermined time has elapsed following the closure of the first switch.

Key touch detector for an electronic musical instrument

An electronic musical instrument incorporates at least two tone signal outputs and controls sound image localization of musical tones in accordance with localization data by changing the levels of at least first and second tone signals provided, respectively, to the tone signal outputs. The instrument includes a tone signal generator for generating a generated tone signal and an output control data production circuit receiving the localization data and providing tone signal volume data and a selection signal. A tone signal output level control receives the generated tone signal and provides the first and second tone signals to the tone signal output. The tone signal output level control has a multiplier for altering the generated tone signal responsive to said volume data to provide one of the first and second tone signals. The tone signal output level control provides a signal corresponding to the generated tone signal unaltered by any multiplication as the other of the first and second tone signals. The tone signal output level control has a pair of selectors responsive to the selection signal for providing one of the first and second tone signals to one of the tone signal outputs and for providing the other of the first and second tone signals to the other of the tone signal outputs, thereby to control sound image localization of the musical sounds of the electronic musical instrument.

Electronic musical instrument having sound image localization circuit

Disclosed are a chord detecting/storing apparatus and an accompaniment information processing apparatus. The chord detecting/storing apparatus designates tones consisting of a chord on a keyboard, and extracts one of the designated notes. Based on the extracted note, the apparatus prepares a row of note bits excluding at least one note. Using this note bit row as an address, the apparatus searches for a chord table in advance where chord information is stored to correspond to each pattern for a row of note bits, and reads out searched chord information to detect a chord. The accompaniment information processing apparatus detects component tones of a chord when the chord is designated from the keyboard, and generates chord information. The accompaniment information processing apparatus produces specific tone information in association with the generated chord information and correlates the specific tone information with the chord information before storing both information items.

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Hamamatsu, Japan

Taichi Kosugi