Very cool, bitluni! I'm surprised at how far you were able to get that much happening with an eight-bit Atmel chip! You could always try out something with an ARM Cortex M4f (many dev kits are less than $20 nowadays), or byte the bullet and go real time with a FPGA. I did a project back in my student days where I used an eight-bit MCU to handle all of the MIDI messaging and dynamic processing, and used a CPLD as my tone generator. It balanced the workload really nicely. Verilog and VHDL certainly aren't my favorite thing in the world to code, but CPLDs and FPGAs are just so good at real time signal control.
It is quite interesting experiments, I'm not familar with arduino, but I'm doing similar experiments using PIC12F1840 controller, and using hardware PWM generator for sound synthesis. Maybe you should go this way with arduino too?
have you looked at using the Arduino Due? A 32-bit core, that allows operations on 4 bytes wide data within a single CPU clock. 84 MHz Clock Same form factor as the Mega. Just a thought. :)
