At 2:46 PM -0400 10/22/01, Larry G. Nelson Sr. wrote:
>I am trying to make a swishing sound by pulsing a pin and feeding it thru
>an RC into an amplifier. I want it to be kind of like a hiss with a gentle
>rise and fall. Not unlike a car approaching and then leaving but as a hiss
>not a roar. Anyone have any solution to keep me from reinventing the wheel?

Well, I am a PIC beginner but also an old school Moog Synthesizer player.

It might be easier to take the analog white noise circuit posted
recently here, and feed it to a simple low pass filter circuit.  Then
alter the LPF so the cutoff frequency can be controlled by the pulse
output...digital potentiometer substituted for a resistor?  The
filter may need a fair amount of feedback to get a nice peaky
frequency response curve.

Anyway, to get a convincing swish sound you need to modulate both the
loudness and the harmonic content.  Sweeping the LPF cutoff will do
that.

cheers, Philip

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body