Crackling, but no xruns - potential reasons

[lilith]

Switched to Ubuntustudio this september and everything was and is working fine. However the last days I occasionally heard some crackling while listening to music on soundcloud. First I thought it's only in my mind but yesterday it was obvious. I switched the CPU governor to powersave and the crackles became more frequent. Now it's working fine again, even with the governor set to powersave. Made some runs with the xruncounter script and always had well above 99.5 % . When the crackles occurred no xruns occurred and I wonder by what this can be caused generally. I once had a similar issue with Renoise when all 4 CPU cores were used and when the DSP load was high.

I remember that @funkmuscle reported a similar issue recently and in his case the CPU was broken. I wonder that a broken CPU can only lead to crackles and I assume that many other problems will appear in parallel (booting, I/O errors, instabilities, etc.).

[LAM]

Hi @lilith,
actually, you have to be sure the CPU governor is on "performance" and not on "powersave".
For crackles i've no solution at the moment but first check if the volume levels are right, sometimes just lowering the volume helps.
Also check Pulseaudio configuration, i had occasional crackles last week when experimenting with Pulseaudio virtual sinks set to 1msec latency.

[lilith]

Hi @lilith,
actually, you have to be sure the CPU governor is on "performance" and not on "powersave".
For crackles i've no solution at the moment but first check if the volume levels are right, sometimes just lowering the volume helps.
Also check Pulseaudio configuration, i had occasional crackles last week when experimenting with Pulseaudio virtual sinks set to 1msec latency.

Thanks, this is basically all clear. I guess the crackles in your case also caused xruns?

[LAM]

Not sure they caused xruns, but sometimes i can hear crackles. Bear in mind that I was experimenting with 2 Pulseaudio virtual sinks set to 1 msec in addition to Jack Sink with OBS, ProjectM, Mixxx, Jack, Firefox and god knows what other program running.
For normal usage i can't hear crackles at all.

[lilith]

I think it really was my ears or jack, etc. crashed. At the moment it´ s working again.