Patchbox OS is a custom Linux distribution specially designed for Raspberry Pi based audio projects. It comes pre-configured for low latency audio performance and pre-installed audio software that will help you get started with your projects in no time!
Do you get xruns or glitches? I would just as soon try someone else's low latency RPi kernel before trying to build my own.
What apps are you running? What are your JACK settings?
I'm using SooperLooper at (JACK) buffer = 128, 3 periods, 44.1 or 48 kHz. Lots of glitching, fair number of xruns.
Added in non-mixer to allow some effects to be put on the loops. DSP (CPU) % is under 40% always.
I tried this last night. Preliminary results with SooperLooper on a Pi 3 are promising, though I was using the HDMI audio out for the test rather than USB audio.
Thought I'd be tricky and add the kxStudio repos for Pi, but those want to be on Debian 10, not Debian 9 as the PatchboxOS is. So then, you'll love this, I did "sudo apt upgrade" and after a couple hours I had upgraded myself right out of a real time kernel back to a stock SMP. Gah! So I started over and was careful not to do that.
Wish I had better news. Keeps locking up. I'm just running qjackctl and hydrogen. Had it going at one point with hydrogen synced to sooperlooper using JACK, but then it locked up. Has locked up about a half dozen times. Doesn't take much effort to make it happen. This is everything the same as when I was running Raspbian Buster. That did not lock up but had some glitches that were bad.
What did I turn off? I turned off "WiFI hotspot" mode. It doesn't lock up any more. However now I can't get rid of the audio crackles. However, no XRUNs are reported. I'm at 256/3 48000 on the Jack settings (USB audio device). I am using the Pi's WiFi to connect to my LAN. Tell me if Ethernet is better for this or not, I can connect using Ethernet.
I installed qjackctl as I am more used to using that but its JACK settings don't take effect even after a reboot.
I turned off Wifi completely and am still getting frequent crackles just playing Hydrogen.
Does this match other people's experience?
PS here are my JACK settings:
/usr/bin/jackd -t 2000 -R -P 75 -d alsa -d hw:U192k -r 44100 -p 512 -n 3 -X seq -s -S
This is almost too much latency and still getting crackles. I've used the same audio interface with an Ubuntu Studio PC and my iPad with Cubasis and QuantiLoop and all of those seemed to work fine with it.
I installed Patchbox OS on my Raspberry Pi 4 last week - it solved a variety of problems I was having with getting native audio ports to work, Jack errors, and general Pi performance. I was having trouble getting VNC resolutions to change and this issue vanished with Patchbox OS as well. I love it!
Things that worked with very little tinkering include:
-Ardour 6.6
-Helm Synth
-qJackctl
-PureData (used to verify midi and audio was working via 'test')
I have also installed Traction Waveform Free, qTractor, and LMMS, abd hope to try Reaper eventually, to see what tools match my workflow. Getting started with Patchbox OS took me from frustration to joy over the course of an hour.
This build is tuned up for music/audio performance and usability! I like the visual patch program right on the desktop, and the terminal config program 'patchbox' for changing configurations which stumped me in the past when they broke, like default audio devices and jack setup.