Date: Wed, 11 Nov 1998 22:36:44 -0800 From: Ted Chapman To: analogue@hyperreal.org Subject: Re: [AH] Odyssey "circular" modulation If you look at the sliders for oscillator control, you will notice that there are switches below each one. (I'm at work now, so I'm trying to do this from memory so bear with me). Below each slider is a switch to select the source, while the slider controls the depth of modulation. OSC-2 has a a slider that can be switched to S&H Mixer, note that this is underlined to make it clear you're getting the ouput of the S&H mixer, not the output of the S&H module (which would be discreet voltages clocked by the LFO). The S&H mixer, in turn, has 2 sliders which can be set (via the switches below them) to take input from oscillators 1 & 2. So then you have a mix of osc. 1 & 2 modulating the frequency of osc 2. You can also have the ouput of the actual sample & hold module (the lfo-determined voltage) routed in as the input to osc-1. This can produce some very interesting shifting chaotic patterns of timbre. What's really cool is that it is also a demonstration to some degree of chaos theory. Although the changes in timbre seem random, they are all mathematically predictable as in the patch I've outlined above there is no randomness (noise ource) involved. If you knew the exact voltages at each controll point, you could predict the output. Kind of a cerebral idea but I find it kind of cool. The noise/ring mod on my machine isn't particularly quiet, but it may be a patch issue (or perhaps something's broken?). The sample and hold is a little wierd, but very powerful. You can mix 2 signals (out of four possible signals) to the S&H input. If I remember correctly, slider one alternates between OSC-1 saw and square ouputs, and slider 2 alternates between noise and osc-2 square. The cv from the mix of the two sources is then sampled at a rate determined by the LFO. Probably the most common use for this sort of circuit (hear often with SH-101 patches) is to use noise as your only source and route the S&H ouput to the filter cutoff, that way you have random filter cut-offs tempo-controlled by the LFO. You can also use it for glissandi by pushing OSC-1 into low frequencies and using the OSC-1 saw ouput, routing this to controll the pitch of osc-2. The Odyssey (and I've only had mine a brief time and it needs some repairs to the ADSR so it's not in top condition) is one of the most powerful mono synths I've worked with to date. It may even push aside my mini as my most beloved mono. The routings are many and varied and absolutely require experimentation. kayana@cyberhotline.com wrote: > > i just got a odyssey how do you do circular modulation like you were > talking about? I can't figure how to sample on the sample and hold ( > it is a weird synth not obvious at all ). Also the noise/ring mod is > very quite is it supposed to be? > > thanks, todd