ftp://ftp.roland.co.uk/productsupport/M ... 110_OM.pdflogicalhippo wrote: How in gods name does the resonant filter work!? Any complicated stuff should be way out of range for such low processing power...
The real question, however, how such a cheap instrument can do digital PWM so well! At low sampling rates, the aliasing caused by a naive implementaiton of PWM would be unbearable! The modern solution is to have bandlimitted "wavetables" for PWM - but this uses way more RAM than could conceivably been on the D50. They must have been doing something tricksy indeed.
i think your answer lies in the D-110 manual... i was looking it over - it looks like the "linear arithmetic" is additive synthesis (with a subtractive interface) - judging by the illustrations on page 91 - it shows how sine waves of different frequencies and amplitudes add together to create the basic square and saw... i know by changing the "phase" of certain additive partials in a square wave you get different pulse widths; alternatively they may use some kind of forumla to change the 'symetry' of the generated waveforms (serge, massive, and helix vsti's have this type of functionality)
resonance is more of a mystery to me... tho admit it does not sound like real resonance... i think its much more interesting than real reso - so yeah thats my guess