Sound/latency issues with 5.4 realtime kernel

Kernels & Hardware, configuring network, installing services

Sound/latency issues with 5.4 realtime kernel

Postby Mr. Lumbergh » 2020-01-26 02:12


I recently saw that the newer 5.4RT kernel was available in Synaptic so I installed it and the vanilla 5.5 64 bit. I'd been using mostly the 5.2RT since Debian is my main workstation for composing and plays nicely with my MIDI keyboard.
The 5.4 though creates issues with sound, specifically the keyboard will cause static in my DAW (LMMS) instead of playing notes, as will a piano roll created using a mouse. After a couple of minutes, it will begin playing notes back correctly with the settings in the DAW (e.g. a piano VST will sound like a piano again and with the same settings). Another odd thing is that it usually starting in the lower registers and gradually the whole keyboard over about 5-10 seconds, but with about a 400ms latency. This is enough lag that it makes playing in time with other tracks impossible.
Are any others having this issue, and has anyone found fixes to enable the same level of audio support as on the 5.2RT? Other differences I've noticed are largely positive, such as Firefox seems to be faster for some reason. If I'm not mistaken 5.2 isn't an LTS kernel, so I'd like to be able to get the newer up and going with the same audio performance as the 5.2 gives me, but I'm not sure where to start.

Any help is appreciated.
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Re: Sound/latency issues with 5.4 realtime kernel

Postby stevepusser » 2020-01-26 20:38

As far as I know, there is only a release candidate version of the 5.5 kernel in Debian Experimental. Are you using an Ubuntu PPA to see the "vanilla" version?

The Liquorix kernel is also low latency and good for audio work. If you add its repository (see to get the latest 5.4 version, does it also have the same problems?
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