Was digging around in my inbox and got an email from this company about another product they offer. While browsing their website I found their PIC version of an Arduino Due/Mega which has a 16-bit ADC/DAC. It is the same price (for me) as an Arduino Due, if you don't count the programmer of course, but I'm wondering if that 4-bits is going to be worth the hassle of having to, probably, radically change your source code and the reference design of the shield.
I was reading about this
chipKIT Max32 board
and looks interesting, it uses the Microchip
PIC32MX795F512
microcontroller but as far as I know, it has 10-bit ADC and no DAC. So it is not pin compatible with DUE.
Maybe using the chipKIT Max32 with an external audio codec, or a DAC, or using the PWM output as DAC it would be possible to digital audio processing.
What I've been worried about is the resolution of the ADC/DAC. Most of the DSP's out there tend to be 24 bits. I was able to find interface instructions for higher end ADC/DAC's on
Arduino Playground
which I'll probably use after I get my pedalSHIELD running (I'll be ordering in late February it looks like).
It is true that modern digital multieffects use 24bits (like the Cirrus Logic
CS4272
codec used in the Line 6 POD X3 Live or in the Axe-FX), but you have to bear in mind that all this codecs are in TSSOP package, which is pretty difficult to solder at DIY consumer level.
Bit depth its important of course, CD audio quality is
16 bits
, so 12 is not that far also considering that the guitar signal is very band limited and not as complex as a hi-fi signal.
Using Arduino DUE ADCs/DACs have a good balance between performance and "friendliness". Arduino microcontroller is not a floating-point DSP processor, but the benefits obtained from writing a distortion/delay pedal with less than 10 lines of standard C code using a free of charge platform can give you loads of fun