Question and issue, Usb Card, Session and more

Dear all,
My goal is to realize a 4 tracks loopstation using SooperLooper with an external controller (midi or osc) and Rpi as core audio device.

I installed a fresh image of PatchBox Os and make all updates automtically at first startup.
I not installed any optional package (ModeP ecc).

I try 3 different usb audio without success.

M-Audio Fasttrack c400 - No sound at all

M-Audio Fasttrack (the cheapest with 1 xlr and 1 hiz)
Works with high latency settings and crack pop sometimes

M-Audio Fasttrack Ultra
Has direct monitoring so I ear the input without latency and can set volume with alsamixer, but the loops sound bad, with some metallic sound and strange modulate/pitching issue

I try a freash raspbian with desktop, installed jackd and sooperlooper and with the Fasttrack Ultra can get 2,9ms ol latency at 88,2khz without any audio glitch.

I cannot understand why I cannot get work it with patchbox os…

With USB audio cards you should use much larger buffer size, at least 512. I’d recommend also sticking to 44100 or 48000 sampling rates.

I did several test and combinations and I had the same issues with larger buffer or different sample rate.
With rasbperry os (without any optimization) I can have 88,2 khz and 128 buffer without glitches.
With Patchbox the sounds on my Fasttrack Ultra are bad in any case…

Try switching to stock kernel using the menu in patchbox, if it’s not already.

Which Raspberry Pi model are you using?

I have a Pi 4 and a cheap 7$ usb stick audio device. I easily reach 48khz and 10ms buffer, even with heavy Sunvox patches. But that’s on default Raspbian. On Patchbox I had lots of issues so i stopped using it. :frowning:

That being said, I’m very interested to know about your 4 track looper, if you want to share any details!

Dear narF,
I’m really busy at the moment, I did some small steps.
I use Mobius Looper on Windows for years and my goal is recreate my Looper with a small and portable hardware and raspberry is a great candidate.
I have a Raspberry PI 3b+, after some test, I set the freq to 48khz with 128 and It is really stable.
I use hardware monitoring for direct input monitor without any latency and SooperLooper has a built in latency compensation for keep all synchronized.

There are many difference btw Mobius and SooperLooper. I write my own scripts for Mobius, my LoopStation model is Ed Sheeran Chewie 2. I saw a lot of live performance and try to reproduce the same behaviours. With Mobius I get it. SooperLooper is based on EDP-4 Gibson Looper and Is a bit different story. I did some test and I start to develop a layer that reads input from pedalboard (is Arduino based and I can send midi or direcly byte via usb/com serial port) and translate into OSC commands for SooperLooper for achive my “looper logic”. My small layer is in .net core becouse I’m a Windows developer :slight_smile: