Focusrite Scarlett Gen 3 4i4 (and others)

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rossmactire
Posts: 2
Joined: Sat Jan 09, 2021 8:17 pm

Re: Focusrite Scarlett Gen 3 4i4 (and others)

Post by rossmactire »

Thank you so much :D now I have somewhere to start. I love this forum so much <3

sadko4u wrote: Tue Jan 12, 2021 8:46 am
rossmactire wrote: Sat Jan 09, 2021 8:26 pm Pardon me if I missed the answer to my question in the thread. I'm very new and a bit of a baby using linux. very little coding/commandline skills but I'm learning.
So it's a good reason to learn Linux better now.
rossmactire wrote: Sat Jan 09, 2021 8:26 pm I just purchased the Focusrite Scarlett 18i8 and want to use it with my ubuntu system. I haven't done anything past open the url link it gives you and got to the part where you download the focusrite controller software which it says isn't supported by the OS I'm using.
Focusrite doesn't support Linux platform. You won't get any driver/software for it from the official site.
rossmactire wrote: Sat Jan 09, 2021 8:26 pm I have the ubuntu 20.4 installed. I was just going to use it with Audacity and LMMS. unless people have better software recommendations.
Ardour?
rossmactire wrote: Sat Jan 09, 2021 8:26 pm PLEASE SEND HELP hahaha.
There is a driver in pocess, and it even works. You'll be required to patch and build your own linux kernel. Please read the detailed information here:
https://github.com/sadko4u/focusrite-scarlett-backports
Ben Tyson
Established Member
Posts: 8
Joined: Sat Mar 21, 2020 1:13 pm

Re: Focusrite Scarlett Gen 3 4i4 (and others)

Post by Ben Tyson »

theotrst wrote: Tue Dec 29, 2020 4:16 pm Are you using the 8i6 3rd gen?
I am, yeah
linux7070
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Joined: Tue Dec 22, 2020 11:17 am

Re: Focusrite Scarlett Gen 3 4i4 (and others)

Post by linux7070 »

sadko4u wrote: Tue Jan 12, 2021 11:42 am
linux7070 wrote: Tue Jan 12, 2021 11:12 am Any idea when this should (roughly) make it to mainline linux kernel, on something like Ubuntu Focal :-(
When the driver will be ready to be shipped to upstream. Currently there are still issues with it.
Hi I noticed your signature.

I'm looking for a Linux multichannel convolver that can map stereo to 8 channels output.

I am using Focusrite 18i20 Gen3 and use convolution for 3-way DSP crossover and room correction with subwoofers.

The digital room correction program I use is Audiolense on Win10 - it can spit out 64-bit floating point WAV impulse response files, to use with whatever convolver.

Appreciate any advice

Thanks!
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sadko4u
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Joined: Mon Sep 28, 2015 9:03 pm

Re: Focusrite Scarlett Gen 3 4i4 (and others)

Post by sadko4u »

linux7070 wrote: Sat Jan 16, 2021 1:22 pm I'm looking for a Linux multichannel convolver that can map stereo to 8 channels output.
You may simulate 8-channel convolver with Ardour and set of stereo convolvers I believe.
LSP (Linux Studio Plugins) Developer and Maintainer.
Ben Tyson
Established Member
Posts: 8
Joined: Sat Mar 21, 2020 1:13 pm

Re: Focusrite Scarlett Gen 3 4i4 (and others)

Post by Ben Tyson »

morke wrote: Thu Jan 14, 2021 11:07 am
Let me describe what I have done, based on your input. [...]
First of all, many thanks for that description, M, it helped me to get my head round what's actually being done in terms of what bits of code are being replaced/changed when patching the kernel.
I don't know if this is something you'd assume would be included in the step of compiling the kernel in your description, but I found that in order to get low latency, it was necessary to specify in make menuconfig -> General Settings -> Preemption Model as described in this article https://hungpham2511.github.io/real-tim ... mptrt.html (if you get a 404 not found, try going to the Archive and finding the article dated 2020/09/05 - the most recent one as I'm writing this. Also the -j20 the author includes in their make commands apparently instructs it to use 20 cores. Only just found that out so no idea how it affects performance to use this). I think enabling the low latency option for the preemption model did make a noticeable reduction in the amount of xruns I was seeing, but there were still enough happening that I wanted to look at other potential ways to reduce.

I've also now repeated the process with the most recent Liquorix kernel and found that it required an extra method (snd_usb_pipe_sanity_check(some stuff)) to be included in helper.h and helper.c. The only difference (I could see) between those and the helper.c and .h files from the apt source 5.8.0-40-lowlatency was the inclusion of that sanity check method so you can safely copy/paste it across, replace the files or patch it in whatever way you like, I think. I copied the files across from the latter to replace those in the Liquorix source, and that seems to have done the trick. I also had to install zstd.
I've only done a couple of hours' worth of actual music stuff with the Liquorix kernel but I'm pretty sure there were significantly fewer xruns than I've seen previously.

One other thing that might be worth a mention is that since I switched to an nVidia GPU, when I boot up a new kernel I have to run dkms autoinstall to make the nVidia graphics drivers work. It's a speedy process, (like >1min on my desktop) and when it boots without the nVidia driver it just falls back on mesa so there's no issues getting to the desktop, sticking dkms autoinstall in a terminal and rebooting. There's probably a way to make it work without the extra reboot but idk what it is and this seems to be working smoothly enough for me thus far.
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