Hi Mark, If you just want to mess with biquads, this is a really good applet for playing around with them: http://www.earlevel.com/Digital%20Audio/PoleZero.html .. it'll show freq. response, but unfortunately won't show impulse response or phase. But, I've found biquads to be a good starting point for filters because there is so much information available on their mathematics and you can create so many different types of filters with them (btw have you checked out Julius O. Smith's site or www.dspguide.com?) There's also Pure Data, which is a free Max/MSP clone. It supplies both real and complex pole/zero functions, and has an FFT function as well. There's a learning curve there, but it's pretty flexible. You'll probably want something to help you solve for gain though if you end up using Pd. Cheers, Louis On Thu, May 6, 2010 at 10:41 AM, Mark Knecht <markknecht@xxxxxxxxx> wrote: > Hi all, > I wonder if there are any Open Source tools for learning > software-oriented DSP, most specifically designing filters? > > I'm an EE but haven't done any real math in years. I just want to > fool around, write some equations, see the results in some sort of > frequency (filter characteristics) or time (impulse response) plots. > > Does anything like that exist? > > I started looking at Octave but it's clearly over-kill so I figured > I'd ask if there was a better platform? > > Thanks, > Mark > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/listinfo/linux-audio-user > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user