[sdiy] Reinventing the wheel? (or ring?)

[Cynthia Webster]

It sounds like the basic principal could be tested with two oscillators
feeding into a Logical AND Gate such as the Serge or Modcan Boolean
modules.  The resulting output pulse could either be listened to alone,
or used to fire a (very snappy) AR or AD type envelope to a VCA gating the
combined VCO output mix.
       ____________________________>
       |                            |
VCO1>--|                            |
        \                           \
         +-AND Gate>    ENV>      VCA>---OUT--->
        /           |___|   |-----| /
VCO2>--|                            |
       |___________________________>|

Maybe the Envelope is not even necessary?
Pulse the VCA right off the and gate itself?

What might be interesting is to provide other logical operations
or even a third VCO with it's own logical input?

Neat Idea!

Let us know how it goes, some sound samples would be cool.

Cynthia



on 8/2/03 6:34 PM, Glen at mclilith at charter.net wrote:

> I have this idea, but I don't know if it's original or not. Let's say we
> take two different oscillators (probably nearly the same pitch, but not
> quite) and we let a comparator look at the instantaneous values of both
> waves. Whenever both waves have exactly the same instantaneous amplitude,
> we toggle an analog switch that decides which waveform get passed to the
> output. Since we trigger the switch when the amplitudes are the same (as
> best as possible), there should hopefully be very little glitching at the
> output (at least in theory.)
> 
> I suspect that the sound at the output would be something vaguely similar
> to ring modulation, but not quite the same. I haven't breadboarded this
> idea yet, so I can't say for sure at this time.
> 
> I have a second idea based on this one. If we could make the switch between
> waveforms depend not only on amplitude matching, but also make sure that
> both waveforms are going the same direction at the time of the switch, it
> should result in a more mellow sound. However, the circuitry to keep track
> of whether a waveform is moving in a positive or negative direction at any
> particular instant, would certainly be an added complication. I doubt that
> such circuitry would be totally foolproof, but maybe it doesn't have to be
> foolproof to work in an interesting manner for this application.
> 
> So, does this sound familiar to anyone? Am I reinventing the wheel? Does
> anyone think the results of such circuitry would be interesting?
> 
> 
> later,
> Glen Berry
>