I completely agree about the need for a generic, filter-coefficient based
filter in Csound. Use a filter design program and put the poles and zeroes
inside the circle and see what happens. Is that what ffitch did to test
them?

-----Original Message-----
From: Josep M Comajuncosas 
To: jpff@maths.bath.ac.uk 
Cc: csound@maths.ex.ac.uk 
Date: Sunday, January 24, 1999 2:37 PM
Subject: Re: TB-303 like Lowpass-Filter




jpff@maths.bath.ac.uk wrote:

> I suspect that if no one can explain why these opcodes are useful, or
> can fix them, it wold be best to remove them from the system.

Dont remove them please! I know tone, reson and the rest are musically
intuitive, but a more powerful too is always welcome...Suppose I want to
design a second order filter ... I can use H. Mikelsons biquad for that.
But for higher order filters the only way to accomplish this is with
filter2. Better if the coefficients can be removed at k-rate. Of course
theyll be unstable in most cases! ... Ill try a stable configuration and
see what happens as soon as I can. Has anyone tried it?
I really need a feature like this. By now I must implement a 3rd order
allpass filter and this is the only way!

Josep M Comajuncosas