I made a recording of electronic drums into a MIDI track. Not that it would matter for this issue, but I then feed this into multiple buses using MIDI key-range plugin for splitting.
I then connected the buses back to the drumset for playback to review a recording. I selected a region and put it in a loop to continuously listen to it. All good, but after like 5 or 7 repetitions the tempo suddenly changed and it became about 20-30% slower.
Restarted Ardour and JACK, same. Later, I believe after a computer restart, it went back to the correct tempo - happy.
Next day, I opened the session and the tempo was again incorrect i.e. 20-30% slower. It did not happen after any changes, or during playback/looping, I just started the computer and then the session.
In both cases, I am 100% sure that I did not touch anything on the Ardour UI. In the first case I actually had the application out of focus. I then looked at the Undo option, the last action that can be undone is “Select loop from range”, also indicating that no action was taken after I instructed Ardour to loop over the range.
The tempo/beat on the Ardour still indicates the defaults i.e. 120.00 and 4/4.
First, how did this happen?
Second, how can I get this back to the original tempo?
What version of Ardour, and from ardour.org or from your linux distribution repository?
There have been quite a few changes to time and tempo handling in the most recent released version (7.5). Not to say definitively that any of the changes address what you saw, but definitely old versions were known to have some problems (mostly around tempo maps).
What version of Ardour, and from ardour.org or from your linux distribution repository?
I installed the Fedora Jam distribution, which provides v6.9.
I then upgrade to v7.5.0 using the Fedora package manager.
I created the session at 192kHz directly in v7.5.
I recorded and edited MIDI.
I have not changed the sample rate in any way in this session.
In qJackCtl (using jack 1.9) Driver is set to Alsa and MIDI driver to seq.
If relevant, under Misc/Other, ALSA sequencer support is enabled.
I did switch from JACK to ALSA and back on this session, trying to troubleshoot the other issue that I’m having with no playback sound at 192kHz, however I think that was after the first occurrence of this tempo issue.
It also sounds like running at a different sample rate than originally.
There’s a chance that PipeWire has issues with 192kHz. I started this session as just a test, and I don’t plan to use 192kHz a lot. But I did end up with a good recording that I don’t want to lose. Is there a way to export the MIDI tracks/buses and import them into another session of lower rate? I will then also be able to confirm whether I encounter this same issue or whether it’s specific to 192kHz.