Suboctave generator - 4013?

[Steve Ridley]

> One might try converting the square waves to pulse waves (I recall, from
the
> dim mists of antiquity, the PAIA Stringz synth doing this -- they ran the
> basic square waves from the main divider into a 4024, applied several of
> the resulting outputs to a collection of NAND gates, and ended up with an
> allegedly violin-sounding  pulse wave........... then again, that might be
too
> much trouble?)

I think that might take it down several octaves, but maybe the pulsewidth
of the suboctave could be adjusted by using the usual PWM technique
(a comparator off the sawtooth or triange) then deriving the suboctave
from the leading edge of one pulse and the trailing edge of the next.
Does my explaination make sense?

> Then, of course, one could put a basic passive filter on the square wave
> output; but I guess that's a little TOO basic for this group.

There's nothing wrong will basic if it works.

It occurred to me that a simple (1 pole) lowpass filter set for a very low
 fc (20 - 50Hz) might be quite interesting on sub bass.  The bass should
increase with falling frequency at 6dB/Octave until clipping occurs.
I wonder how this would match the bass roll off in our hearing.  Just a
thought - I haven't tried it...


Steve Ridley