A few questions about DSP

[otaviomad]

So I've been studying the idea of making a real time auto-tune using an ESP32. I have some idea of how to do the waveform manipulation however that's still mostly in the sketch phase. What I could use some help with is getting to understand how the adc sampler and dac output works. Since I'm new to all this stuff, I'm gonna land a barrage of questions. I'd appreciate if any at all get answered, or maybe even point me into the right direction to find the answers myself:

- It is my understanding that the ADC and DAC just aren't cut for audio I/O. The DAC I get, it's only 8bit, but the ADC is 12bit, why is it that it's bad?

- If I work initially using the built-in DAC and then later down the line switch to an external I2C DAC, would it be easy to port my code?

- How does the DSP library work? I know that's a pretty general question however if I were to make, say, a simple reverb effect on the sound that's coming from the ADC and then output it through the DAC, how would I do it?

- How would I go about transferring the audio data to my PC via serial communication? I'd like to analyze the spectrum of the signal before the ADC, after the ADC and then after the DAC. While they're in analog form, I can easily output it to an oscilloscope, however when digital, I need to do it on my computer.

I apologize for having so many questions at the same time, however I'm still somewhat confused and enthusiastic about all this. Thanks!

[Jakobsen]

Hi Viomad

Yes lots of questions - but with your enthusiastic drive - you just need to get your hands dirty.
Get one of the lyra boards they all have external ADC/DAC and get going using one of the examples from the ESP-ADF framework.

From there you can think about how to implement your application.

The ESP-ADF is build to simplify an audio pipeline class of application fx a reverb effect. And here you will find out that in most cases it will be dam more easy to do the FFT of the audio data on the ESP and just send the mag/frequency response in limited number of bins via monitor to the PC.

Hope to kick you in the wright direction.

[otaviomad]

Hey, thanks for the suggestions! I've looked into the LyraT boards and apparently they don't have enough spare input and output pins available. I intend to use an ILI9341 touchscreen, that will take up a lot of space. Not only that, I also intended to implement a few pedals along the way. If I use an external DAC and ADC, would I be able to use ADF?

[Jakobsen]

Hi
Yes just study the Lyra sch - external ADC/DAC only requires 4 x io pins for I2S (Audio) and 2 x io pins for I2C lines (Control).
Rest is free for you
/j