Abstract: An audio filter and corresponding method with through-zero linearly variable resonant frequency are described. An example method includes receiving an input signal; receiving one or more control input signals; and providing a resonant filter for electronic music for processing the input signal. The resonant filter can include an exponential times linear multiplication to produce the resonant frequency control responsive to control voltages exponentially for musical octave/semitone control, and linearly for timbre modulation, the waveform being invariant over corresponding exponential changes in pitch of both input signal and filter resonance. The linear modulation can include inverting the sign of a bandpass feedback based on the sign of the resonant frequency variable so as to maintain stability. In the example method, to prevent a glitch on the output when frequency changes sign, a separate highpass output signal may be generated.

Abstract: Methods and systems for generating oscillatory timbres for musical synthesis through synchronous ring modulation are described. An example method performing hard synchronization comprising using first and second oscillators, the first oscillator being a fundamental oscillator which provides a fundamental frequency, the second oscillator being a modulation oscillator operable at a frequencies higher than the first oscillator; and in response to the fundamental oscillator completing its cycle, synchronizing the modulation oscillator to the original point of its waveform. Ring modulation may be performed on the synchronized output by multiplying it by a waveform of the fundamental oscillator, such that the ring modulation is synchronized to produce a variety of oscillatory timbres. The method can create a variety of unique sounds having musically pleasing characteristics. A real-time audio signal can be used instead of the first oscillator to produce dynamically varying timbres.

Abstract: A multi-core audio processor includes a plurality of data ports configured to receive and transmit data, wherein a first data port of the plurality of data ports is configured to receive data associated with a first stream, a first plurality of audio interface resources configured to perform operations on the data, and a multiplexing unit configured to route data between the plurality of data ports and the first plurality of audio interface resources, the multiplexing unit including a multiplexer associated with each of the first plurality of audio interface resources. The multi-core audio processor also includes a first plurality of transport buffers, at least one transport buffer associated with each of the first plurality of audio interface resources. A first set of buffers of the first plurality of transport buffers is configured to synchronously store data received from the first set of the first plurality of audio interface resources.

Abstract: A multi-core audio processor includes a plurality of data ports configured to receive and transmit data, wherein a first data port of the plurality of data ports is configured to receive data associated with a first stream, a first plurality of audio interface resources configured to perform operations on the data, and a multiplexing unit configured to route data between the plurality of data ports and the first plurality of audio interface resources, the multiplexing unit including a multiplexer associated with each of the first plurality of audio interface resources. The multi-core audio processor also includes a first plurality of transport buffers, at least one transport buffer associated with each of the first plurality of audio interface resources. A first set of buffers of the first plurality of transport buffers is configured to synchronously store data received from the first set of the first plurality of audio interface resources.

Abstract: An audio filter and corresponding method with through-zero linearly variable resonant frequency are described. An example method includes receiving an input signal; receiving one or more control input signals; and providing a resonant filter for electronic music for processing the input signal. The resonant filter can include an exponential times linear multiplication to produce the resonant frequency control responsive to control voltages exponentially for musical octave/semitone control, and linearly for timbre modulation, the waveform being invariant over corresponding exponential changes in pitch of both input signal and filter resonance. The linear modulation can include inverting the sign of a bandpass feedback based on the sign of the resonant frequency variable so as to maintain stability. In the example method, to prevent a glitch on the output when frequency changes sign, a separate highpass output signal may be generated.

Abstract: Methods and systems for generating oscillatory timbres for musical synthesis through synchronous ring modulation are described. An example method performing hard synchronization comprising using first and second oscillators, the first oscillator being a fundamental oscillator which provides a fundamental frequency, the second oscillator being a modulation oscillator operable at a frequencies higher than the first oscillator; and in response to the fundamental oscillator completing its cycle, synchronizing the modulation oscillator to the original point of its waveform. Ring modulation may be performed on the synchronized output by multiplying it by a waveform of the fundamental oscillator, such that the ring modulation is synchronized to produce a variety of oscillatory timbres. The method can create a variety of unique sounds having musically pleasing characteristics. A real-time audio signal can be used instead of the first oscillator to produce dynamically varying timbres.

Abstract: The present disclosure provides a multi-channel morphing digital audio filter, including methods and systems for real-time interpolation between a plurality of fixed frequency responses. Real-time interpolation may be performed simultaneously along three separate axes. Various embodiments of the present technology include receiving, in real-time via a digital filter module, at least one acoustic signal and one or more control input signals indicative of one or more corresponding interpolator values. The methods and systems may further include determining one or more filter coefficients based on a linear interpolation in an encoded space of a plurality of fixed frequency responses, generating a filter from the one or more determined filter coefficients, and applying the generated filter to the at least one received acoustic signal. In some embodiments, frequency and amplitude (i.e., angle and radius) of poles and zeros of the filters may be processed independently, and poles may be unconditionally stable.

Abstract: The present disclosure provides a multi-channel morphing digital audio filter, including methods and systems for real-time interpolation between a plurality of fixed frequency responses. Real-time interpolation may be performed simultaneously along three separate axes. Various embodiments of the present technology include receiving, in real-time via a digital filter module, at least one acoustic signal and one or more control input signals indicative of one or more corresponding interpolator values. The methods and systems may further include determining one or more filter coefficients based on a linear interpolation in an encoded space of a plurality of fixed frequency responses, generating a filter from the one or more determined filter coefficients, and applying the generated filter to the at least one received acoustic signal. In some embodiments, frequency and amplitude (i.e. angle and radius) of poles and zeros of the filters may be processed independently, and poles may be unconditionally stable.

Abstract: A method and apparatus for printing a one-dimensional, continuous signal, such as a sound wave, as a printed pattern and for recovering the sound wave from the printed pattern. The method decomposes the one dimensional signal two-dimensional function that is continuous in both dimensions. The two-dimensional function can be printed as a pattern on to a paper substrate using a standard printer. The audio signal is recovered by scanning the pattern and processing the scanned values.

Abstract: An asynchronous sample rate tracker based on a phase-locked loop quickly locks to an input sample rate, even when the input sample rate equals the resident, or internal, sample rate of an asynchronous digital sample rate converter. The phase difference between the input write data and output read data is maximized to reduce data lost due to excursions in the input sample rate. In one embodiment, a binary shift register is used to generate a read pointer step size according to the derivative of the difference between a write pointer position and a read pointer position.