From cadsi.com!kent@elvis.cadsi.com Thu Nov 17 14:12:46 1994 Date: Thu, 17 Nov 1994 13:38:31 -0600 From: Kent Williams Reply to: cadsi.com!kent@cadsi.com To: electronica+@andrew.cmu.edu, casio@cadsi.com Subject: Casio (was Re: analog) On Nov 17, 12:06pm, Ab Wilson wrote: > The only Casio synth I'm really familar with is the CZ101. Since all > the CZ series have the same archetecture I feel I can generalise my > views to all of these. I've got a collection of nearly 200 patches for the CZ, so there's a lot of different sounds you can make. It is one of those synthesizers where you can spend a lot of time specifying how each note will sound, but for which there is very little you can globally vary about a performance -- no free-running LFO's. The real strength of the old analogs was that different modules could be set up to sync with other modules, or simply to modify other modules asynchronously. That's why I want a midi-fied serge modular. The CZ-1 has a velocity sensitive keyboard with aftertouch, which can interact very nicely with the CZ architecture; you can individually set velocity sensitivity for the pitch envelope, amp envelope and waveform envelope. My favorite trick is to make pitch and amp relatively insensitive and make waveform very sensitive, meaning that different key pressure gives you a different waveform. > > One thing I've always wanted to know about Casio synths was what the > big different was between the PM synthesis as used in the CZ series > and the iPM as used in the VZs. Can anyone give an authoritive answer? > The CZ has a digital architecture that goes kind of like this DCO1->DCW1->DCA1-+ | +---> Mix/Ring Mod/Noise | DCO2->DCW2->DCA2-+ There are 6 different waveforms possible, and the DCW envelop varies between a sine wave (DCW level 0) and the 'full' waveform (DCW level 99). Morphing the waveform from a sawtooth to a sine for example, sounds a lot like closing a steep non-resonant filter. The Noise modulation is really just mixing a noise source on line 2 with the tone source on line one. The VZ series works something like FM (perhaps equivalent on some level to FM, without infringing on Yamaha patents, if you get my drift). You have 8 oscillators in pairs of two. Each oscillator can be a sine, one of 4 types of sawtooth, or two types of noise. Each pair can be internally mixed, ring modulated, or 'phase' modulated. The four pairs are set up such that they either get mixed to the final output or phase modulate another pair. There are no filters! What is phase modulation (or phase 'distortion')? I've not figured out exactly. Something like this: If source A phase distorts source B, the momentary value of A controls distortion of B's slope. At amplitude 0, B is unmodifed; at maximum amplitude B's slope is changed drastically. The net effect is that if you phase distort a signal with high amplitude signal, it gets pretty dirty and fuzzy. If you set all the lines to sine, set all modulation paths to phase mod, and set the amplifier envelopes to be full on when a note is played, you get a really evil noise like a guitar fed through multiple distortion boxes. The really weird part comes when you fool around with velocity sensitivity; For each step in the amplifier envelope for a line you can enable or disable velocity sensitivity. This makes it very easy to come up with heavily distorted unpredictable sounds. It's also very hard to get an idea for a sound in your head and then implement it. The presets seem to be very sparing in their use of phase distortion. They're also not very interesting. I would dearly love to get a decent editor for this thing and give it a good workout. Does that answer your question? -- Kent Williams -- kent@gilligan.cadsi.com Look in the mail header for all sorts of vital information about me. Go on, EMOTE! I was RAISED on thought balloons!!