I wrote a long code for 4 independent effects.
The conversion delay is 30 μs. This is quite sufficient to get a clean enough sound.
As I understand it, this time is obtained due to the output conversion. Optimization of the ADC does not lead to faster conversion.
I’m making a device for a bass guitar, maybe for this reason speed is not so important for me.
but the issue is that, even by recompiling linux with the real time patch, I still had the sound chopped off for 50ms every second
could'nt figure out why
so now I go bare metal (no linux) just wrote a short little program , and it's the only thing that runs
I had to port the bcm2835 lib (keeping only SPI and PWM features)
still the high frequencies are hard to keep, the issue comes mainly from the mcp3002 wich is quiet slow
but the fact is that pedal pi is definitely not a ready to go solution to make guitar digital effects
Sorry my english is not very good.
Pi pltforma is not very suitable. It does not have a hardware ADC and therefore requires additional components. The processor clock speed does not matter since you still run into the speed of ports working with the ADC. Considering all the above, 50 μs is an excellent result.
I settled on a hardware solution using Arduino. I am using the nano version. If you want to get really high quality sound, the DUO version is suitable for you. It has unsurpassed performance of a 12-bit ADC and an integrated hardware DAC.
As an artist to an artist, I would use PI as a control element that will provide a large screen, mouse and keyboard, and I would perform sound conversion using Arduino DUO.
We get a high hardware speed DUO and user-friendly interface under the control of PI.
Here is my idea using NANO. I use a small 64 * 128 screen and an encoder with a button to select the operating mode. I use about 30% of the controller resources NANO.
Pi is an incredibly powerful platform for this task, but it is loaded with the OS because working with it is not very effective.