Delayed stuttery playback in 3.7.1 and mp3 for first 10-15sec of track

[pato]

I recently installed 3.7.1 on new powerful desktop pc (AMD chip equiv to Intel i9, 64gb RAM, Win11). I record and playback voice on mono tracks @ 48000khz/24 bit through a Focusrite Solo interface with a newly updated driver.

Problem: Playback on this pc of an Audacity track or an mp3 exported from it (192 kbps, constant bit rate, 48000hz) is usually delayed and stuttery/echoey for the first 10-15 seconds, after which playback smooths out and sounds ok. The problem is definitely playback on this pc. An mp3 recorded in Audacity on this pc plays back fine on another pc, and an mp3 recorded on the other pc that plays back ok on it has the same delay/stutter problem when played back on this new pc.

What could be causing the problem, and why does it seem limited to the first few seconds of playback? It occurs regardless of whether I start playback at the beginning of a track (or mp3 file) or part way through it. Thanks.

[Trebor]

@pato

What could be causing the problem,

Let's talk about the Audacity rewrite: One core isn't the game anymore

Alright… so I created an issue on the Audacity Github page explaining how Audacity would screw the hell out of just one core on my laptop, basically running the first core on my i9 at 100C or 212F temperature wise, which if you know anything about CPU temps, that’s basically the max temp, and it keeps it like that for as long as Audacity is recording, even if it’s offscreen. CPU temps such as this stress systems and can quickly kill a system much quicker than not, way more or less depending on …

[pato]

I think I found the answer: The problem seems to be caused by a too-small buffer size setting in the Focusrite interface. Increasing the buffer size from 192 to 1056 seemed to fix the problem. This solution was suggested by a troubleshooting paper on the Focusrite website. The underlying technical explanation for the connection between buffer size and playback glitching is beyond me – and I’d think this computer’s fast chip could handle anything – but that’s not my concern as long as things work.

[pato]

Intermittent glitchy playback NOT solved: I thought the solution was increasing buffer size. Wrong. Problem recurs intermittently. Specifically, when problem occurs:
– Recording: Start is delayed by 1-2" after pressing Record button.
– Playback: Start is also delayed 1-2" after pressing Play. Initial fraction of second of recording is cut off, then stutters and repeats self for 5-10" before sounding normal. Problem is solely on playback; exported track sounds OK when exported to mp3 (192kbps) and played back on another computer.
This occurred with varied buffer size settings from 128 to 1056.

Then later, recording & playback were ok with varied buffer sizes from 128 to 1056. I’m mystified and frustrated at the problem, especially intermittency. It’s stopping my work cold.
Help please!

[pato]

Further diagnostic testing shows the following:
– After system works ok for a while, then goes to sleep either on my command or at its own initiative, when system awakes the playback stuttering resumes.
– After full system restart, playback works ok again (at least for a while).

Why should system going to and awakening from sleep cause resumed playback stuttering?