1. Pitch Shifting and Dynamic Filtering Rossum (1992a) Digital sampling instrument for digital audio data; Rossum (1992b) Dynamic digital IIR audio filter and method which provides dynamic digital filtering for audio signals

2. Digital sampling instrument for digital audio data Multi-channel interpolative playback of digital audio data stored in a waveform memory provides improved interpolation of musical sounds by using seven or eight surrounding points. Allowed a high channel count, enhanced access to waveform memory to allow improved performance parity between computational units and memory. Also, the present invention includes techniques which dramatically reduce the amount of memory required to store the musical waveforms while still maintaining adequate bandwidth and fidelity in the output.

4. The traditional approach to implement a sinc function interpolation has been to store the above coefficients in a table in memory. The present invention uses a similar approach as sinc function, but stores the function in memory as a seventh or eighth order impulse response of a filter having deep (>90 dB down) notches at integral multiples of the sample rate and peaks only 60 dB to 70 dB down at half- integral multiples of the sample rate.