A signal processing circuit, for each string of a musical instrument which string is individually tuned to a frequency, includes a transducer adjacent to the string and an equalizer connected to an output circuit. To emulate an acoustic instrument, the equalizer is set to emphasize a signal present in a frequency range of the tuned frequency of the string and/or its harmonics. It also de-emphasizes at least low end frequencies below the operating range of the string. A mid-range frequency device is provided in the equalizer to produce characteristic mid-range response for a specific acoustic instrument. If the transducer produces an inherent resonance at a characteristic frequency, the equalizer will also de-emphasize the inherent resonance produced by the transducer at the characteristic frequency of the transducer.

A system for enhancing sound quality comprising a filter that square roots the instantaneous amplitude of frequencies in an input signal for generating artificial harmonics corresponding to said frequencies. The system can comprise an automatic level control that momentarily boosts the amplitude of artificially generated harmonics to emphasize attack transients occuring within the input signal.

This patent describes an invention providing electronically-induced drive environments for one or more mechanically-vibrating physical elements, including those environments applicable to musical instrument application. One aspect of the invention provides for visual indication of one or more drive levels in very general electronically-driven vibrating-elements environments. Other aspects of the invention provide for loop signal processing and the use of external drive sources applicable to a variety of types of sense transducers, drive transducers, and vibrating elements in isolated or grouped configurations. Additional aspects of the invention provide for pluralities of drive transducers and drive signals as applied to individual or groups of vibrating elements within the invention's environments. Yet further aspects of the invention provide for advantageous use of piezo drive transducers and hall-effect sense transducers within the invention's environment as alternatives to electromagnetic transducers.

A method of manipulating a complex waveform by considering the harmonic and partial frequencies as moving targets over time in both amplitude and frequency and adjusting the moving targets by moving modifiers in both amplitude and frequency. The manipulation of harmonic frequencies and the synthesis of harmonic frequencies are based on the harmonic rank. The modifiers move with the movement of the frequencies based on rank. Harmonic transformation modifies, by rank, the waveform from one source to a waveform of a second or target source. Harmonics and other partials accentuation identifies each of the frequencies and its relationship to adjacent frequencies as well as fixed or moving thresholds and make the appropriate adjustment. Interpolation is also disclosed as well as models which imitate natural harmonics.

Synthesis of time-varying MIDI control signals useful in creating spatial perturbation, chase effects, new forms of rich musical timbre modulation, spatially-distributed timbre constructions, and other types of sonic animation. Phase staggered multi-channel MIDI-format control signals are created using one or more low frequency oscillators, each with a plurality of phase shifting elements. Control signal waveshapers may be included in the control signal synthesis chain. In an exemplary embodiment, frequency and phase parameters are adjustable, with values that may be recalled from stored program control and/or modulated in real-time by incoming MIDI control signals. In another exemplary embodiment, each outgoing control signal additionally may be independently assigned a selectable waveshape, which is determined by values that may be recalled from stored program control and/or modulated in real-time by incoming MIDI control signals.