posted 29 January 2001 08:34            

tchebyholy.kym tchebyholy.zip

Attached is a sound file containing generators for the "Holy" spectra of Max Mathews and John Pierce. These are generated by wavetable synthesis on waveforms created by summation of Tchebyshev polynomials with 3 dB/octave falloff. Included are the AIF wavetables and text files containing the Smalltalk code to generate these tables.

The "Holy" spectra are constructed such that no higher partials fall within a critical bandwidth of one another (approx. 20%). Hence, they have holes in their spectra at certain harmonics.

Also included is one example of an intentional "Unholy" spectrum that has bunched harmonics within a critical bandwidth. It sounds much more harsh than the others due to beating in the ear.

These spectra were constructed out to harmonic 17, and so are usable only below 1.5 KHz without alias artifacts (about 90 nn).

Enjoy...