Alright guys, a bit of background. I'm an electronic musician and have just recently got into the Arduino game. My first and most recent project has been a MIDI output device that triggers drums (in Reason) from piezo sensors. Now I have delusions of grandeur and began planning my next project:
I want to make a bitcrusher pedal. That is, a pedal (sometimes called a stompbox) that will take input from a condenser microphone, guitar, etc., convert it to digital, truncate a selected amount of bits, and output the result as audio. I'll have some extra elements to make it more than boring old ADA conversion (including tube amplification), but I want to make sure I've got all my bases covered before I even begin thinking about building it. Here's what I think I need:
I've got two problems. First, the Arduino only has 4-bit A/D conversion. For audio input, we're gonna need more than that. So I'll be outsourcing A/D conversion to something like this: http://focus.ti.com/lit/ds/symlink/pcm2705.pdf
Second, is it possible for the Arduino to receive data that fast (48kHz), process it, and spit it right back out? Further more, do I NEED the D/A converter, or can the Arduino use PWM to output the result? I know I can program the rest, but the actual digital input/output is where I need guidance. Thanks guys.
Almost! I suppose I could use it for prototyping. My two problems with this are obviously the lower processing bitrate, (10-bit sound is not the best) but what about the output bitrate? Is there anyway to tell, since the output appears analog once we use PWM?
And then again, i thought taht the general idea of a bitcrusher was to get LOFI sound
I didn't quite elaborate enough. One of my primary features is going to be using an external variable resistor to modulate the amount of bits being read. I.e., sweepable effects. I don't want a huge decrease in sound quality the moment I turn the thing on.
It ideally would be in realtime. Looks like the guy on the instructable did it well enough, even incorporating the 3 pots.
1.) Get some experience by building the Lo-Fi pedal in the Instructable
2.) Add the tube amplification
3.) Add ADC, look into using a different microcontroller, DAC, etc.