Leland Stanford Junior University

Analog Devices,inc.

Other

Scott A Van Duyne

Julius O Smith

Timothy S Stilson

Kim Cascone

Gregory P Scandalis

David A Jaffe

Sean M Costello

Kord F Taylor

John R Pierce

Nicholas J Porcaro

Daniel T Petkevich

Complex sound events are created by generating multiple different kinds of simpler sounds with randomly varying repetition rates. The average repetition rate can also be variable. The values of sound parameters such as wave selection, pitch distribution, pan distribution and amplitude distribution can have random distributions, as determined by various control inputs, some of which have their own random distributions.

Statistical sound event modeling system and methods

Computer-implemented techniques are provided for synthesizing sounds of an internal combustion engine vehicle using a physical model of the vehicle. In general terms, the method includes independently generating and/or synthesizing separate components of the vehicle sound, then combining these components to produce a final sound. Using a physical model of the vehicle, the separate components of the vehicle sound are independently generated from vehicle control parameters characterizing the operating conditions of the vehicle. The components are then combined using mixers and equalizers to produce a realistic vehicle sound. The present technique allows independent control of the separate components of the vehicle sound, is not limited to specific vehicles, and does not require recorded sounds taking large amounts of storage space.

Apparatus and methods for synthesis of internal combustion engine vehicle sounds

An efficient digital waveguide synthesizer is disclosed for simulating the tones produced by a non-linearly excited vibrational element coupled to a resonator, such as in a piano. In a preferred embodiment, the synthesizer creates an excitation pulse from a table containing the impulse response of a piano soundboard and enclosure. Alternatively, this excitation pulse can be synthesized by filtering white noise. The excitation pulse is fed into a filter that simulates the collision of the piano hammer and string. Because the hammer-string interaction is nonlinear, the characteristics of this filter vary with the amplitude of the tone produced. The filtered excitation pulse is then fed into a filtered delay line loop which models the vibration of a piano string. Because the excitation pulse already contains the effects of the resonator, the tone produced by the delay line loop does not require additional filtering in order to model the resonator.

Efficient synthesis of musical tones having nonlinear excitations

A coupled mode digital filter which simulates any number of arbitrarily tuned modes coupled together so as to share the same loss element at a junction loaded by an arbitrary impedance function is formed from the combination of one first order allpass filter �28! and one unit delay �30! per mode and one shared coupling filter�36!. This coupled mode digital filter may be excited by a stored or generated excitation signal, or a filtered excitation signal, to produce inharmonic percussive sounds and musically interesting two-stage and beating decay envelopes resulting from natural coupling of modes of near frequencies

Method for inharmonic tone generation using a coupled mode digital filter

A sampled data, non-integer delay line interpolation structure includes a sampled data delay line, two allpass filters, each having an associated read pointer for reading data at a corresponding integer position of the delay line, an alternating crossfader that alternatingly crossfades between the outputs of the two allpass filters, plus a controller that controls when the read position of each allpass filter is updated and also controls when the filter coefficient of each allpass filter is updated. A specified delay length value is sampled by the controller each time the crossfade orientation of the alternating crossfader is changed, and from that value the controller generates a new read pointer and filter coefficient for allpass filter to which the structure will next crossfade. The new read pointer is an integer that corresponds to an integer portion of the specified delay length, and the filter coefficient corresponds to a fractional portion of the specified delay length. After updating the read pointer and filter coefficient of one allpass filter, the alternating crossfader outputs the signal generated by the other allpass filter for a first number of sample periods until the updated filter 'warms up.' Then the alternating crossfader crossfades to the signal generated by the updated allpass filter over a second number of sample periods. At the end of the crossfade operation the specified delay line length is sampled again, the reader position and filter coefficient of the other allpass filter is updated, and then the crossfade operation repeats.

System and method for generating fractional length delay lines in a

A music synthesizer includes main resonator, such as a digital waveguide network, that is coupled to a digital passive nonlinear filter. The passive nonlinear filter receives traveling wave signals from the resonator and generates modified traveling wave signals having a different frequency spectrum than the received traveling wave signals without changing the received traveling wave signals' energy content. The passive nonlinear filter then transmits the modified traveling wave signals back into the resonator. The passive nonlinear filter includes a first memory element for retaining an internal energy state and a dual-mode signal generator that generates the modified traveling wave signal from the received signals and the internal energy state using a first signal processing method when the internal energy state has a negative value and using a second distinct signal processing method when the internal energy state has a positive value. The dual-mode signal generator preferably includes a two-level amplifier that multiplies the internal energy state by a first coefficient when the internal energy state has a negative value and by a second distinct coefficient when the internal energy state has a positive value so as to generate an adjustment signal. A first signal combiner combines the received signals with the adjustment signal so as to generate a next value of the internal energy state, and a second signal combiner combines the adjustment signal and the retained internal energy state to generate the modified traveling wave signal that is transmitted into the resonator.

Passive nonlinear filter for digital musical sound synthesizer and method

A signal synthesizer uses a digital waveguide network having at least a three dimensional matrix of waveguide sections interconnected by junctions to filter one or more excitation signals so as to generate an array of synthesized output signals. The digital waveguide network has sets of waveguide sections interconnected by junctions. Each waveguide section includes two digital delay lines running parallel to each other for propagating signals in opposite directions and each junction has reflection and propagation coefficients assigned to it for controlling reflection and propagation of signals in the waveguide sections connected to that junction. Except for junctions along boundaries of the digital waveguide matrix, a majority of the junctions are 2.sup.w -way junctions, where W is an integer greater than 1. In a preferred embodiment a majority of the junctions are multiply-free tetrahedral junctions that each interconnect four waveguide sections so as to scatter and intermix signals in flowing through those waveguide sections. At least one signal source, coupled to specified junctions of the digital waveguide network, provides excitation signals to the digital waveguide network. In addition, a parameter memory stores sets of control parameters, including waveguide control parameters for controlling how the digital waveguide network filters signals propagating therethrough and signal source parameters which govern the excitation signals produced by the signal source or sources. Finally, a digital signal processor or controller operates the signal sources and digital waveguide network using a selected set of the control parameters so as to synthesize an array of output signals.

Multidimensional digital waveguide signal synthesis system and method

A signal synthesizer uses a digital waveguide network having at least a two dimensional matrix of waveguide sections interconnected by junctions to filter one or more excitation signals so as to generate an array of synthesized output signals. The digital waveguide network has sets of waveguide sections interconnected by junctions. Each waveguide section includes two digital delay lines running parallel to each other for propagating signals in opposite directions and each junction has reflection and propagation coefficients assigned to it for controlling reflection and propagation of signals in the waveguide sections connected to that junction. Except for junctions along boundaries of the digital waveguide matrix, each junction is at least a four-way junction that interconnect at least four waveguide sections so as to scatter and intermix signals in flowing through those waveguide sections. At least one signal source, coupled to specified junctions of the digital waveguide network, provides excitation signals to the digital waveguide network. In addition, a parameter memory stores sets of control parameters, including waveguide control parameters for controlling how the digital waveguide network filters signals propagating therethrough and signal source parameters which govern the excitation signals produced by the signal source or sources. Finally, a digital signal processor or controller operates the signal sources and digital waveguide network using a selected set of the control parameters so as to synthesize an array of output signals.

A musical sound synthesizer simulates interaction of a hammer having a compressible striking surface with a resonating medium. A digital waveguide resonator that simulates operation of a resonating medium and generates digital resonator waveforms representing signals propagating in said digital waveguide resonator. A hammer filter simulates the hammer striking the resonating medium and generates first and second hammer waveforms. The hammer filter includes a scattering junction that couples the hammer filter to the digital waveguide resonator. The hammer filter also includes a compression function that generates from the first and second hammer waveforms a compression value corresponding to compression of said simulated hammer, a stiffness function that generates a time varying stiffness coefficient as a function of the compression value, a excitation signal function that generates a hammer excitation signal as a function of hammer strike impulses, and a hammer function that generates the first hammer waveform as a function of the compression value, the hammer excitation signal and the second hammer waveform. The scattering junction transmits the digital resonator waveforms received from the digital waveguide resonator unchanged back into the digital waveguide resonator when the compression value corresponds to the hammer not being compressed and otherwise transmits a first time varying portion of the first digital resonator waveform combined with a second time varying portion of the digital resonator waveforms, wherein the first and second time varying portions of the first digital waveguide waveform and the digital resonator waveforms, respectively, are functions of the compression value.

Music synthesizer system and method for simulating response of resonant

A microtonal key module includes a central key and a number of surrounding keys clustered about the central key. The central key and the surrounding keys establish among each other a progression of successive microtonal increments. A plurality of such microtonal key modules are arranged to form a microtonal keyboard system.

Growing community of inventors

Stanford, CA, United States of America

Scott A Van Duyne