To add to Sean Costello's list of books, there is an impressive book
on filter design which I have bought but not read yet:

  Digital Filter Designer's Handbook
     With C++ Algorithms  2nd Edition

  C. Britton Rorabaugh

  McGraw Hill 1997  ISBN 0-07-053806-9

It comes with a floppy disc of source code.  Amazon.com has it for
USD$69.50.

It is a magnificent-looking book, but it assumes more knowledge of
calculus, z-transforms, real and imaginary numbers and the like than I
have at present.  It is clear that there is no alternative to knowing
this stuff if you want to do DSP in the frequency domain.

Sean also wrote:

> P.S. Robin, when is the DevilFish unit generator coming out? :)  
> I'd love to have a digital simulation of an overdriven diode ladder 
> filter available in Csound, with the output being used to
> FM the cutoff...

Life is too short either to:

1 - Write a piece of software which behaves like the Devil Fish
    (my modifications to the Roland TB-303).

or 

2 - Wait for that software to produce audio.

It is way too complex and idiosyncratic.  Its not just a question of
complexity, non-linearities and simulating diodes etc.  There are the
matters of needing instant feedback for Filter FM based on the output
of the filter (ksmps = 1!) and of running at much higher sample rates
then 44.1 kHz in order to simulate all the chaotic gyrations which
actually occur - of which we hear the lower frequency components.

Take a look at the waveform which forms the backdrop of the Devil Fish
sound samples page:

    http://www.firstpr.com.au/rwi/dfish/sounds/

    http://www.firstpr.com.au/rwi/dfish/sounds/df-waveform-q90.jpg

If I get a piece of software kicking and gyrating even vaguely like
the Devil Fish, I will be very proud of myself!

The Devil Fish is complex for a piece of electronics, but it is simple
compared to the reverberation of a room or a guitar sound box.  Don't
even think about cymbals, gongs, sitars, sarods or tympanies!

- Robin


===============================================================

Robin Whittle    rw@firstpr.com.au  http://www.firstpr.com.au
                 Heidelberg Heights, Melbourne, Australia 

First Principles Research and expression: Consulting and 
                 technical writing. Music. Internet music 
                 marketing. Telecommunications. Consumer 
                 advocacy in telecommunications, especially 
                 privacy. M-F relationships. Kinetic sculpture.
                  
Real World       Electronics and software for music including:
Interfaces       Devil Fish mods for the TB-303, Akai sampler 
                 memory and Csound synthesis software.