Hello
I am currently involved in a project to record multiple tracks live in studio using a Focusrite 18i20 4th generation, a new PC build, and Ubuntu / Ubuntu pro Real-time kernel. Using the standard install of Ubuntu, Audacity AppImage, a Focusrite USB interface, and ALSA / ALSA Control Panel, Audacity is currently requiring a latency adjustment of -134ms using a buffer size of 100 and a adjustment of -71ms using a buffer size of 50. With my current configuration (see details below) should our current latency and buffer size suffice for overdubbing and multi tracking up to 8 tracks simultaneously at 24 bit depth and 48k bit rate?
Current Specs
Ubuntu 24.04.04, Kernel Version 6.17.0-14 generic / 6.8 RT, Gnome 46, Wayland
Audacity 3.7.7 AppImage
Gigabyte x870 Aorus Elite Wifi 7
Intergrated AMD graphics
Gskill 32GB DDR5 6000mhz
Western Digital sn850x 1GB
Focusrite 18i20 4th Generation using ALSA / ALSA Control Panel
Furthermore what would be the best resource for the configuration of the Ubuntu Pro Real-time kernel for Audio / Audacity? I am are currently having difficulty with its current configuration, the latency testing results using Real-time are about double the latency described above.
Thanks in advance for any advice
I’m a Windows guy, but…
Does your interface have direct hardware monitoring? I believe most of the Focusrite interfaces do. If you can monitor without going through the computer you won’t have latency.
You can still monitor a backing track from the computer and align the recordings with latency compensation. As you may know, that’s what the compensation is for. It doesn’t eliminate the latency.
latency testing results in about double the latency described above.
There MIGHT be a playback/monitoring buffer plus a recoding buffer. And, 100ms is too long even if not doubled. 
Somehow, I don’t think Audacity’s buffer/latency tells the whole story. Or maybe the operating system has an additional buffer???
Or, I’m pretty sure your Focusrite has ASIO drivers so you can try Audacity with ASIO. But I don’t know if any of that runs on Linux.
Given the information you have supplied, my feeling is that you are coming at this from the ‘wrong’ angle. You have very decent hardware available to you but trying to use Audacity to get your desired result seems like a road to pain, I think. Audacity is an audio editor and you’d be better off with a DAW.
You don’t say if the PC is solely for audio production so let’s assume it is. You could bolster your existing setup by adding the Ubuntu Studio components using the instructions here: Ubuntu Studio installer. Alternatively, you could start from scratch and install Ubuntu Studio, AVLinux or Fedora Jam. All these are customised for audio work.
As far as a DAW is concerned Ardour and Waveform Free are both fully-featured and free. Reaper and Bitwig Studio are NOT free but have trial versions and, like the free offerings, run natively on Linux. Of course, the downside is they take more learning than Audacity does.
My advice would be to do some more research even if you choose to disregard everything else I said. This is especially true if the project you are involved with cannot be repeated.
I hope that helps in some way.