Multi-effect Guitar Pedal

[Tom_91]

Hello there,

I would like to build a multi-effect guitar pedal with effect fully calculated by an electronic card, that can go up to 6 effects in series or more. At the end I would like it to be powered on battery.
I saw that the Teensy card was an interesting one, with its audio module.
I did some arduino before, and I am willing to learn how to programm on the Teensy card.

I just want to clear my doubts, know what you think about the achievability of the project, and if the latency will be reasonable (<5ms).

Do not hesitate to say anything that could help me doing this project

Thanks for your pieces of advice

 

[MarkT]

Its definitely powerful enough. Battery life is perhaps something to give consideration to. Latency can be tuned by reconfiguring the block size, the default is 128 samples at 44.1kSPS, giving just under 3ms latency for many operations (not counting ADC/DAC latency though - that is also something to look into, but its usually a lot less than 128 samples.

 

[h4yn0nnym0u5e]

Here’s a thread where latency is not only discussed but actually measured for the unmodified system, and practical experience of reducing it touched upon.

Teensy is very fast, so for 6 effects you may be able to clock it more slowly to reduce power consumption (150MHz is apparently quite a significant reduction). A slower CPU clock does not increase latency.

Others who’ve made pedals have gone the other way, and maxed out the CPU with all sorts of clever amp models etc.; not 100% sure, I’m a saxophonist, not a guitarist! You should be able to find relevant threads on the forum, with a bit of searching.

 

[Tom_91]

Thanks a lot for your answers.
The latency might be a bit high regarding my personnal setup and music.
I saw that the Daisy Seed from Electrosmith was also a very interesting microcontroller for processing sound. What do you think of it against a Teensy 4.1 ?

And very often, people are using custom PCB such as the Terrarium for the Daisy Seed to make a pedal guitar. I do not exactly understand the purpose of using a PCB, soldered with resistors, buttons, and potentiometers, just to calculate the sound with the microcontroller.
Can't we just use a breadboard, the microcontroller, and some wires to connect : aux in/out, and alimentation ? (I think I might not understand some electronic principle ?)

 

[h4yn0nnym0u5e]

The latency might be a bit high regarding my personnal setup and music.

Only you will know he answer to that, and then maybe only if you try it out…

I saw that the Daisy Seed from Electrosmith was also a very interesting microcontroller for processing sound. What do you think of it against a Teensy 4.1 ?

No idea. There may be someone here who knows enough about both to give some sort of answer, but a lot will depend on your own priorities and skill.

And very often, people are using custom PCB such as the Terrarium for the Daisy Seed to make a pedal guitar. I do not exactly understand the purpose of using a PCB, soldered with resistors, buttons, and potentiometers, just to calculate the sound with the microcontroller.
Can't we just use a breadboard, the microcontroller, and some wires to connect : aux in/out, and alimentation ? (I think I might not understand some electronic principle ?)

For a one-off project, in fairly skilled hands, wiring it up without a PCB is fine. For consistent performance and ease of assembly, and making your design available to a wider audience, a well-designed PCB makes everyone’s life a lot easier. But a poorly designed one confers no advantage, can perform worse than hand wiring, and may reduce your options if it doesn’t quite do what you want.

My recommendation is to do a lot of research, by Googling and reading because no one will do it for you. Then ask specific technical questions that your research hasn’t given a clear answer to, and demonstrating you’ve put the effort in: asking how Daisy Seed compares to Teensy suggests you haven’t bothered to research either properly; asking how to get Teensy latency down, on this forum, and referring to relevant threads which haven’t given you quite enough information, suggests you have.

Then you “just” have to start out and build something, but be prepared to abandon or re-purpose it if it can’t achieve your goals. This can happen, but it’ll only have cost you some time and money, and you will at least have some experience out of it.

Yoda was wrong: sometimes you have to try, in order to see if you can do … and re-try is an option.