Hi, I never tried coding filters with the Arduino UNO, I have seen some conversations going in the Arduino forums, but I cannot give you much help on this topic: forum.arduino.cc/index.php?topic=498059.0
Hi there, I'm also curious about this issue
If it's possible to create EQs or filters on Arduino boards, that's AMAZING cuz u can even load the frequency characteristics of a 4x12 guitar cabinet or a Celestion speaker and turn it into a CABINET EMULATOR !!!!!!!(which is a treasure for "bedroom guitarists") Furthermore, generate a white noise at the output, send it to an amp, collect the output sound pattern from the amp by using a reference-level RTA testing microphone connected to the input of the pedal (48-volt bias power might be required, but that's just a minor problem which could be fixed via a phantom box ), and analyze the signal and then load this pattern into the Arduino Cab Sim... It's actually like a Bias Amp's Matching System or a Kemper Profiler's Profiling system. Would it be great?
Check the Mozzi Library, it is (kind of) compatible with the pedal. Here's a couple of tests I made, I don't remember how good or bad it was however, it's been a little while. These should be the ones I had better results with...