Thank you so much!
Sorry for the late reply but i had a ton of stuff to absorb and learn!
These are what i got:
*Oversampling. You need (4^n * Fniquist), where n = number of bits. For the Due ADC this is 12. That is a lot of samples. Even if i did that, the buffer that holds my values would be filled very quickly. In practice, this means that guitar sound stored in buffer would be extremely small, making effects like delay useless. So it is out of the question.
*This article (http://www.djerickson.com/arduino/due_adc.html) was awesome! Especially the AREF method and reducing ADC time via changes in the settings code. I will read more into this!
*Calibration and averaging. These methods seem ok in general though i don't understand them completely. I think the correction margin i get will be small (i have TONS of noise)
*The meat of the info you sent me was this library: https://github.com/delsauce/ArduinoDueHiFi
This was so awesome because it uses the ADC of the codec. Though i have some questions about using codecs.
The way i do things in my code, i get the ADC values (the audio in from my guitar) and store it into a buffer.
uint16_t sDelayBuffer0[40000];
This buffer alone almost flls up my entire DUE memory. I t can hold a maximum delay to a little less than 3 seconds.
So after the guitar input is stored, effects are applied to it and then it is sent to the DACs.
How do i implement effects with an external codec? Can the codec "send" me the quantized values so i can store them inside my DUE's RAM so i can apply the effects? Can this library help me with getting the info from the codec to store inside my uint16_t buffer?
The documentation is rather poor, but i think this lib has what i want to finish my project! I think 24 bit values are too much, i will use 16 bit ADCs. And if i can store them from the codec, i will figure out a way to deal with their size. Maybe use an external memory. It needs 100 us to access 32 bytes... This seems satisfying. If i can get data from the codec to my DUE i will see what i can do with memory