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Old 08-19-2018, 10:07 AM   #6
Jack Winter
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Join Date: Aug 2007
Location: Luxembourg/Spain
Posts: 1,809
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Well then I don't think you are going to get all that far...

I feel sorry even though I'm in no way personally responsible for Linux audio. Personally I think that distros should do a better job at this, though low latency audio is probably not a concern for most...

It would probably work a lot better if you tried something like https://www.bandshed.net/avlinux as it does this by default for you.

Otherwise do the following:

1. Install a lowlatency kernel, should be in your repos.

2. Make sure that you reconfigure the system so that you get the ability to run realtime threads and lock memory. Normally accomplished by editing a file called limits.conf in /etc/security (the details might wary slightly depending on your distro). add the following and login again:
your-username - rtprio 98
your-username - memlock unlimited

3. Verify that the above worked by running the command ulimit -a

4. Make sure that JACK is running realtime (preferably at priority 80), this is pretty easy if you are starting it with qjackctl.

These changes should already allow you to go a lot lower in latency.

If you need even lower latency without xruns, I'd recommend getting hold of a realtime kernel, and to install and configure the rtirq script to configure your soundcard interrupt to run at a priority 95. There might be another couple of minor tweaks, like making sure that the cpu doesn't go into power save states, etc, but that would be more or less all that one typically would have to do to get really low latency.

It might also be very helpful for you, if you were to add the http://kxstudio.linuxaudio.org/index.php repos to your xubuntu, as that would give you access to quite a lot of good linux audio programs, and fix potential problems with the software distributed by ubuntu.

When did you try alsa with reaper? The ALSA midi support was recently added.

I don't think it would hurt at all to have both linvst and airwave installed. Linvst seems complicated, but once you get the hang of it it's not very hard. It also comes with some scripts to automate the procedure, though I've never tried as I made my own before they were available. Basically you install the linvst package, then you probably should remove the .so files that airwave installed along side your vsts (same name as the .dll but ending in .so). finally either run the scripts to set it up, or manually copy linvst.so to plugin-name.so.

I think probably at this point the biggest problem is that you don't have a lowlatency kernel, and that you haven't setup limits.conf properly. Also running JACK without realtime privs isn't helping. Hope this was helpful and not too confusing

You are also welcome to visit the freenode irc channel #reaper-linux, where it probably would be a lot easier and faster to help you. Also check out the following link, it's a bit dated right now, but I intend to fix it up a bit: https://wiki.cockos.com/wiki/index.php/REAPER_for_Linux

Break a leg!
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Reaper for Linux Documentation (WIP). Software: Archlinux/KDE, Fabfilter FX, Komplete 8, Nebula, Schwa/Stillwell, T-racks Max/Amplitube/SVX, etc. Gear: i7-2600k/4700HQ/16GB, RME Multiface/Babyface, Behringer X32, Genelec 8040, etc. :)
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