I think that’s probably the wrong sort of filter to use for a wah effect as it passes all frequencies equally. All-pass filter - Wikipedia
Also, the “hz” parameter must be a FLONUM (floating point number) and not a sound, so you can’t use an oscillator for the “hz” argument.
If you click the “Debug” button for your effect, you should see an error message, something like:
error: bad argument type - #<Sound: #b3a0b450>
Also there is either an error in the manual, or a bug in Nyquist because the manual says that “Q” is optional, but in fact a “q” value is ‘required’.
(hp) (reson) and (areson) can have a sound for the hz parameter, so you could try something like:
;control f "medium frequency" int "[Hz]" 1000 100 4000
;control fl "lfo frequency" real "[Hz]" 1 0.1 5
(reson s (sum f (mult f 0.5 (lfo fl)))(/ f 2.0) 2)
Yes. See here:
http://www.audacity-forum.de/download/edgar/nyquist/nyquist-doc/xlisp/xlisp-ref/xlisp-ref-157.htm
You may be better to use (simrep)
http://www.audacity-forum.de/download/edgar/nyquist/nyquist-doc/manual/part6.html#index426
I’d suggest leaving that one for a little while. It’s a lot more complicated that it appears.
Come back to it later, but read this section in the Nyquist manual about the “Transformation Environment” Behavioral Abstraction (I’ve read this section dozens of times, and sometimes I still get caught out by it).