Music Signal Processing

NRI has developed a number of powerful and quite appealing next-generation signal processing technologies and techniques for electronic music and professional audio. In addition to their stand-alone value and significance, most of these technologies and techniques are well-suited to make component sound-scape contributions to (the extremely interesting areas) of spatially-distributed timbre construction within a stereo or multi-speaker sound-field.

1. MULTI-CHANNEL SIGNAL PROCESSING FOR MULTI-CHANNEL MUSICAL INSTRUMENTS

A first group of NRI technologies for music signal processing pertains to multi-channel signal processing for multi-channel musical instruments.

1.1 Multi-Channel Processing for Multi-Channel Musical Instruments Signals

In this NRI technology, multi-channel audio signal processing systems and techniques are provided for electronic instruments having multiple and distinct output channels. Such systems may be used in conjunction with instruments comprising multiple vibrating elements, each with a dedicated signal output. Each received audio signal channel may be directed to a dedicated or shared signal processor for variably changing selected attributes of pitch, timing, timbre, and amplitude in ways that are unique for each signal. Signal processors may be shared using an allocating mixer, allocating switch, or both. An output mixer may be used to mix signal processor output signals into one or more outgoing mixed audio signals. Signal processors, mixers, and switches may be configured by stored program control and controlled in real-time. Real-time pitch variations can be used to change the pitch organization of fixed-pitch vibrating elements within an electronic musical instrument.

1.2 Phase-Staggered Multi-Channel Signal Panning

In this NRI technology, phase-staggered multi-channel signal panning is used to create pleasing-to-sensational degrees of spatial sound-field perturbation and chase effects for subtle or dramatic application, and may be swept with control signals from a low-frequency oscillator, transient envelope, or other source. Phase-staggering and modulation parameters may be stored and recalled and/or modulated in real-time by arbitrary control signals, including parameters derived from the original input signal using NRI technologies described in sections 1-2 of Music Control. This technology may be used individually or in conjunction with other signal processing and signal synthesis techniques in creating new forms of rich musical timbres, and can be used as a powerful tool in the extremely interesting areas of spatially-distributed timbre construction.

2. SPECIALIZED SENSATIONALIST SOUND SIGNAL PROCESSING

A second group of NRI technologies for music signal processing pertains to the production specialized and sensationalist sounds. Although these sounds have excellent application to backdrop sound frameworks, these sounds are especially are capable of providing extraordinary rich and powerful capabilities for musical soloing.

2.1 Signal Processing for Twang and Resonance

In this NRI technology, a number of audio signal delays, each with high resonance positive feedback, distortion characteristics, and selectable delay times corresponding to a desired resonant frequency, provide twang and resonance synthesis for moments of sparkle or vibrantly-responsive ongoing backdrops. Selectable delay times can be used to tune the resulting resonance(s) to a musical scale or other resonant frequency distribution, mimicking the rich ‘buzzing’ array of sympathetic strings employed in many traditional South Asian musical instruments. Delay, feedback, and signal processing characteristics and parameters may be recalled from stored program control or modulated in real-time by arbitrary control signals, including those derived from the amplitude or other attributes of the audio input signal. The technology may be used individually or in conjunction with other signal processing and signal synthesis techniques in creating new forms of rich musical timbres, and can make astonishing contributions when used in spatially-distributed timbre construction.

2.2 Envelope-Controlled Time and Pitch Modification

In this NRI technology, amplitude-envelope controlled time-modulation and pitch-modulation are used to add rich, previously-unheard, attention-getting aspects to solo lines and chords. The amplitude envelope may be measured from the signal being modulated, a delayed version of this signal, or another signal source. In some configurations the resulting sounds may be compared to tape-speed manipulation and an ‘automatic’ “DJ scratching.” Modulation characteristics and parameters may be stored and recalled or modulated in real-time by arbitrary control signals, including those derived from the amplitude or other attributes of the audio input signal. The technology may be used individually or in conjunction with other signal processing and signal synthesis techniques in creating new forms of rich musical timbres. The technology may also be used in spatially-distributed timbre construction.

2.3 Controllable Frequency-Reducing Cross-Product Chain

This NRI technology is a highly-controllable extension of the inventor’s earlier work published in Electronotes #98 in 1979 which has been commercialized a few times by various vendors since that publication. It can be surprisingly easily and economically implemented in DSP software. A real-time controllable mix of a plurality of multiple output frequency-reduced signals and the cross-products of these signals provides rich animated harmonically partitioned spectra. Mixing parameters may be stored and recalled or modulated in real-time by control signals provided by envelope generators, low-frequency oscillators, and those derived from an original input signal such as the amplitude of an original input signal. The real-time controllable mix may have multiple outputs and be subjected to further signal processing and multiple-channel amplification. The technology may be used with dramatic effect in spatially-distributed timbre construction.

3. LUSH RICH-TIMBRE SIGNAL PROCESSING

A third group of NRI technologies for music signal processing pertains to lush rich timbre production.

3.1 Signal Processing for Cross-Flanged Spatialization

This NRI technology is a multi-channel cross-flanger with differing modulation signals for each flanger element arranged to deepen synthesized and vibrating element sounds. In a very nice electric guitar configuration, the arrangement processes outputs from several distortion signal processors, each driven by a related signal, to create new levels of animated distortion richness. Each distortion signal processor may be driven by an output of a multiple-output spatializing signal processor. The characteristics and parameters of the processors and modulations may be stored and recalled or varied by real-time control signals, including those derived from the original input signal. The invention may be used individually or in conjunction with other signal processing and signal synthesis techniques in creating new forms of rich musical timbres. The technology may also be used in spatially-distributed timbre construction.

3.2 Layered Signal Processing for Individual and Group Output of Multi-Channel Electronic Musical Instruments

This NRI technology provides rich timbre performance, composition, and recording environments for an electronic musical instrument with multiple vibrating elements providing multi-channel output. The vibrating elements instrument produces at least one group instrument output signal responsive to the vibrations of a plurality of vibrating elements and at least two individual instrument output signals each responsive to a unique vibrating element. An individual signal may be applied to pre-filtered pitch-transposing signal processors to add stable, rich, responsively re-enforcing bass tones. Another individual signal may be applied to emphasis signal processing to emphasize a particular melodic line, note in a chord, etc. A wide variety of traditional and novel rich-timbre signal processing techniques may also be employed. The technology may be used individually or in conjunction with other signal processing and signal synthesis techniques in creating new forms of rich musical timbres and spatially-distributed timbre constructions.

3.3 Envelope-Controlled Dynamic Layering of Audio Signal Processing and Synthesis

This is NRI’s most stunning, sophisticated and disruptive signal processing technology for string and wind instruments with applications to voice and synthesized sound. Parallel operations on the amplitude envelope of a single-channel or multiple-channel electronic instrument or vocal signal may be used to control rich layered audio signal processing and/or audio synthesis environments. The controllable layered audio signal processing and audio synthesis environments may comprise dedicated or shared processor and synthesis elements, respectively, though use of pre-mixing and merging operations. Detection operations performed on the envelope of an applied audio signal may include level detection operations, rate sign (i.e., level increasing versus decreasing) detection operations, and rate magnitude detection operations. These operations may control rich layered audio signal processing environments and/or audio synthesis environments directly, while other embodiments may incorporate the use of state machines in the control chain. The applied audio signal may be pre-processed by signal processing before application to envelope detection, and combinations of such envelopes may be used. Hysteretic effects may be invoked across increasing and decreasing variation in envelope parameters. Traditional string and wind instruments simply are transformed into entirely different subtly beautiful things.

Issued Patents

TitlePatent NumberApplication NumberPriority DatesPDFText OnlyRelated Patents
Multi-channel signal processing for multi-channel musical instruments8,859,87610/676,24905/15/1999PDFText Music Signal Processing
Phase-Staggered Multi-Channel Signal Panning8,035,02410/702,26205/15/1999PDFText Music Signal Processing
Envelope-Controlled Time and Pitch Modification8,030,56610/703,02305/15/1999PDFText Music Signal Processing
Signal Processing for Twang and Resonance8,030,56510/702,41505/15/1999PDFText Music Signal Processing
Signal Processing for Cross-Flanged Spatialized Distortion7,652,20810/702,94105/15/1999PDFText Music Signal Processing
Layered Signal Processing For Individual and Group Output of Multi-Channel Electronic Musical Instruments7,309,82910/722,14505/15/1999PDFText Music Signal Processing
Controllable Frequency-Reducing Cross-Product Chain6,849,79510/703,13705/15/1999PDFText Music Signal Processing




Pending Patents

TitlePublication NumberApplication NumberPriority DatesPDFText OnlyRelated Patents
Envelope-Controlled Dynamic Layering Of Audio Signal Processing And Synthesis For Music Applications2005/012087011/040,16305/15/1999
11/05/2003
PDFTextMusic Signal Processing

Pending Unpublished Applications

TitleApplication NumberPriority DatesRelated Patents