Richard Dobson wrote:

> Re allpass filters in Csound: Hans Mikelson himself posted several a
> while back (relating to nested allpasses for Gardner reverbs). Perhaps
> it's time for a revival?

Thanks for the tip.  Mikelson's orchestra for the Gardner reverbs is
available at http://www.werewolf.net/~hljmm/csound/gardverb.orc. I was
actually trying to implement a reverb described in a Gardner article,
although the original source was in a JAES article by Joe Dattorro. The
cool aspect of the Dattorro reverb is that it uses interpolating taps in
the allpass delay lines, modulated by a low frequency (~1 Hz) sine wave.
The modulation of the delay lines results in dynamic alterations of the
resonant frequencies, to decreate tonal coloration.  So far, my reverb
has a tendancy to clip internally and/or blow up, so the Mikelson
orchestra should help in properly implementing the allpass stages.

BTW, has anyone on the list tried implementing any of the feedback delay
network (FDN) reverbs as described by Stautner and Puckette, Jot, Julius
Smith, etc.?  They seem promising.  I'll probably try to design such a
reverb this weekend, and will post it if and when I get it working.