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Old 10-11-2018, 08:50 PM   #20
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Join Date: Mar 2008
Location: Planet Earth
Posts: 3,910

Originally Posted by JamesPeters View Post
So I just tried the Liquorix kernel and appended limits.conf with:

james - rtprio 98
james - memlock unlimited

(Yeah I'm real original with my username on my computer.)

And then I rebooted, and tested Reaper again.

I'm not able to set any lower latency with the sound card. The CPU usage increased slightly. However Reaper remains more responsive when it's loaded down at 80%+. That's the only difference I noticed. I'm probably going to undo those changes, go back to the stock MX Linux kernel.

I was getting the same low latency as in Windows already with the stock kernel, so I wasn't expecting miracles in that regard. I'm pretty sure this card wasn't really intended to be as low latency as 1.5ms/1.5ms.

(edit) man changing this stuff is fast!

I reverted to the stock kernel and removed that stuff from limits.conf. CPU usage went down in Reaper. Responsiveness is actually about the same overall. Lesson learned for that kernel. I wonder if the more recent kernels are just better at this sort of thing. I'm a bit late to the game to know.
Yeah, I wouldn't expect you to get real super low latency out of that card. I have that same Xonar card in my HTPC machine in my living room, because I needed the TosLink interface to connect to my receiver's TosLink inputs so it can do the D/A conversion for Dolby Digital 5.1 audio. That machine is a Windows based BeyondTV server and client.

I'm guessing you have two of "the same" audio device and their driver in Windows allows them to work (sync) together. I've seen that with M-Audio devices. Anyway that'd be great for anyone who wants that functionality, another win for Linux audio.
Yep, they are two identical M-Audio Delta 2496 cards, with the first one acting as the clock for both itself and for the other card over SPDIF. In Windows they appear as one device with twice the inputs/outputs, and midi interfaces. In REAPER for Windows I can right click the record button and on the audio entry of the menu I see all the ins and outs of the first card followed by all the ins and outs of the second card.

I have a 4-channel template setup for my acoustic drums that gets the first two channels from the first card and the second two channels from the second card. Actually I have the same thing setup in REAPER for Linux, but it currently requires me to fire up Qjackctrl to get all four channels of input.

Here's what the routing looks like in Qjackctrl, that I am hoping can be achieved with just REAPER and ALSA.

Hear My Music - Click Me!!!
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