Go Back   Cockos Incorporated Forums > REAPER Forums > REAPER for Linux

Reply
 
Thread Tools Display Modes
Old 07-23-2018, 09:02 AM   #1
audiojunkie
Human being with feelings
 
audiojunkie's Avatar
 
Join Date: Nov 2011
Posts: 971
Default ALSA vs JACK latency experiences

My understanding is audio apps run with lower latencies with JACK than with ALSA. What has been everyone's experiences with this? My initial testing seemed to confirm this, but I wanted to know what everyone else was experiencing.

Thanks!
audiojunkie is offline   Reply With Quote
Old 07-23-2018, 09:57 AM   #2
David Else
Human being with feelings
 
Join Date: Mar 2012
Posts: 610
Default

I don't think this is the case as JACK runs on top of ALSA. I have not tested myself.
__________________
----------> Debian Linux Distribution = Computing Joy & Freedom <----------
David Else is offline   Reply With Quote
Old 07-23-2018, 11:19 AM   #3
audiojunkie
Human being with feelings
 
audiojunkie's Avatar
 
Join Date: Nov 2011
Posts: 971
Default

Quote:
Originally Posted by David Else View Post
I don't think this is the case as JACK runs on top of ALSA. I have not tested myself.
That's what one would think logically. :-) However, there are several reports of xruns like crazy in ALSA and smooth running under JACK (and surely vice versa as well). It made me think that it may have come down to applications not being specifically "tuned" to work on ALSA, whereas JACK is tuned to work on ALSA, and apps are tuned to work on JACK. That's the only thing I can think of that might cause this. But either way, I'm trying to determine if there is any truth to it, and if Reaper works better in one verses the other.

So, what is everyone's experiences when running in ALSA vs JACK? How low can you get your latency before XRuns when using each technology?
audiojunkie is offline   Reply With Quote
Old 07-23-2018, 11:37 AM   #4
audiojunkie
Human being with feelings
 
audiojunkie's Avatar
 
Join Date: Nov 2011
Posts: 971
Default

Continuing with my research on this topic, I found the following conversation from the Mixxx Community Forums to be interesting:

https://www.mixxx.org/forums/viewtopic.php?f=1&t=460

This seems to indicate that there is NO added latency, which would indicate that JACK itself is at least equal to ALSA latency-wise. I suppose it is still possible for badly behaving apps in the JACK chain to cause latency. And it is also possible, I suppose, that when an app is tuned better for a particular technology (ie ALSA vs JACK) than another, then things could run better on one vs the other. That clears up a lot! So, it comes down to this:

Does "REAPER" run with lower latency and less Xruns when using straight ALSA, or through JACK when tested on the same REAPER project?
audiojunkie is offline   Reply With Quote
Old 07-23-2018, 11:57 AM   #5
Jack Winter
Human being with feelings
 
Jack Winter's Avatar
 
Join Date: Aug 2007
Location: Luxembourg/Spain
Posts: 1,922
Default

I think that would need testing and might even differ between systems.

FWIW, I suspect that ALSA might have the edge, as reaper then has exclusive access to device, with JACK there might be other clients and there is some code overhead.
__________________
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. :)
Jack Winter is offline   Reply With Quote
Old 07-23-2018, 01:41 PM   #6
audiojunkie
Human being with feelings
 
audiojunkie's Avatar
 
Join Date: Nov 2011
Posts: 971
Default

Quote:
Originally Posted by Jack Winter View Post
I think that would need testing and might even differ between systems.

FWIW, I suspect that ALSA might have the edge, as reaper then has exclusive access to device, with JACK there might be other clients and there is some code overhead.
It is definitely confirmed that ALSA has the edge with CPU cycles. The developers themselves have confirmed that JACK uses more CPU cycles than ALSA alone. But they strongly affirm that JACK itself causes no latency. So ALSA definitely has the edge in that area. :-)
audiojunkie is offline   Reply With Quote
Old 08-23-2022, 09:21 PM   #7
Nemo08
Human being with feelings
 
Nemo08's Avatar
 
Join Date: Jun 2008
Location: Philippines
Posts: 54
Default Xruns or sound interruption

if i am using jack , i have xruns coming from time to time by groups of 10 or 20 , uif i use Alsa , it will be a sound interruption while playing a project.i had the best result with alsa 48000 , 512 ,3 , MB internal HD snd device , no-RT.Some time i can play the whole project without anything happening.What is giving me sometime these troubles , any idea?
Nemo08 is offline   Reply With Quote
Old 08-25-2022, 10:39 AM   #8
4duhwinnn
Human being with feelings
 
Join Date: Mar 2017
Posts: 859
Default

Hi, I would look at the list of apps and services that 'auto-start' and remove all that are verified as not system critical, and just start them if needed when not recording. Before starting a session, I would unplug any ethernet cable, and turn off any bluetooth apps/hardware, then unmount and unplug any extra external drives.

I have an i7 4-core 8-thread cpu, @ 3.40 ghz and use 44100/128/2 settings, with 3 to 6 ms latency. There are some software effects and instruments that make noises seemingly unrelated to available resources, and need special attention when used. Core and thread coding among daws and plugins also vary quite a bit. Reaper leaning towards the excellent end of the spectrum.

https://www.cpubenchmark.net/cpu.php...0+3.40GHz&id=1

If this behavior is new to your system, and was better in the past, then some updates, upgrades and new versions might include troublemakers. Your package manager might have a log to inspect.

If you can install an extra avlinux/ubuntu-studio distro on an external drive,
they have a config well tuned at the outset, for an easy comparison.
Cheers
__________________
Songs I've made with linux and Reaper, a qwerty forehead danger zone:
https://www.youtube.com/watch?v=NtlO...RvGI8-_TqqZ7ij
https://franklincheney.bandcamp.com/

Last edited by 4duhwinnn; 08-25-2022 at 12:06 PM. Reason: useful link
4duhwinnn is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 06:28 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.