[sdiy] standard filters from ladder topology?

[Magnus Danielson]

From: "JH." <jhaible at debitel.net>
Subject: Re: [sdiy] standard filters from ladder topology?
Date: Mon, 5 Sep 2005 01:23:02 +0200
Message-ID: <002201c5b1aa$ac20baf0$0200a8c0 at jhsilent>

> 
> > I could see the ebenfit to making a voltage tuned filter
> > with specific response... but I have some doubts as to
> > how it would sound in a synth application. I'd expect that
> > the difference would be subtle as best ???
> 
> It's about a filter for BBD-based physical modelling.
> Subtle changes in the passband might alter the overtones on
> which the whole thing is resonating. Or maybe it
> doesn't make a difference. I just want to be prepared.

For that application I think you will enjoy using either a Butterworth or
Bessel filter. The Butterworths maximum flatness keeps the passband free, but
the group delay is not really optimum. The Bessel/Thompson is much better in
this respect with a fairly quite passband, but benefits in maximum flatness of
group delay, which would show up as a slightly added delay to that of the BBD,
so that is certainly usefull. If you care about phases, Chebyshev variants is
not for you.

Cheers,
Magnus