My current version of Audacity is 3.7.5, although I’ve noticed this bug for a while.
I first noticed it when recording podcasts; I would record the remote party’s audio as a backup. Then when I receive their local copy, my copy would gradually go out of sync (become shorter).
Today I am recording music and notice the same thing: throughout a song, the track I record gradually goes out of sync, with the newest track being shorter.
Even though it is by such a large amount it is highly unlikely to be human error, I generated a click track, exported a copy, recorded that copy, and it gradually goes out of sync with the original (becomes shorter).
Seems the same as the issue reported here:
In that thread people blamed that user’s hardware and said no one else is having this issue, I primarily want it to be known that I am also experiencing this problem.
I am needing to use the effect>change tempo on every new track in multi track projects just to sync them up, and a large amount of data is not being captured.
Is it always the same computer? There are two standard digital sample rates. CD (normal) at 44100 and video at 48000. The ratio between them is 1.08843537. Is one show that number faster than the other? If it is, you may have something set to the wrong rate.
A 5 minute show may appear as 5 minutes and 26 seconds, or slows down to 4 minutes and 58 seconds. My numbers may be off, but you get the idea.
Anything that arrives in analog to your computer has to be whacked up into digital segments by the clock inside the sound card. Nobody wrote that clock has to be accurate.
When the movie people shoot separate sound, the clocks inside the sound recorder and the camera are stunningly expensive to make sure they say in sync with each other in spite of having no connecting wires.
It’s a “bug” when you can find a bunch of different people on different computers with exactly the same problem. I think you may have a sloppy sound card.
I have tried checking my systems audio sample rate, it is set to 48KHz. I start a new project in Audacity, go to the settings, set the project sample rate and the default sample rate to 48KHz. The issue persists. I repeat the above steps, setting the sample rate to 41.1KHz with no change.
Also, I don’t think it’s a sample rate problem, because the percentage I have to apply the tempo change by is not the same every time.
I’ve been trying to use my new Behringer UMC404HD, but today I also plugged in my Alesis MultiMix 8 USB 2.0 FX that I used on this computer this time last year without any issues. I also tried the analog microphone input in my GA-Z97X-UD5H-BK motherboard. Different amounts of desync, but always a desync that has to be corrected with the tempo change effect.
Maybe the Behringer, Alesis, and Gigabyte products are sloppy?
Is there a list of sound cards that are known to be supported?
Is it something to do with a recent Linux update? I use a rolling release that has had a lot of updates since this time last year, when I was sure I recorded multiple tracks in Audacity without the desync.
The clock (oscillator) that generates the sample rate is always imperfect to some extent. If the recording is long enough the equipment will always drift-apart.
Some consumer soundcards are off by enough to cause pitch errors, when played-back on a different computer/soundcard and the tempo can off by the end of a song and that makes it impossible for musicians to with different computers to collaborate.
Or, sometimes someone will sing into a USB mic in-tune with a backing track from their soundcard and when the vocal and back are mixed the voice is out-of-tune with the backing track.
Some pro setups use an atomic master clock and equipment that has an externa clock input. Besides being very precise, the master clock allows multiple devices to be locked-in to the exact sample (but the devices have to be local).
I’ve been using Audacity for a long time so it’s the music editing app I know my way around in, but it’s been about a year since I last recorded a multi-track project. I wish I had a more specific time when the issue started, or some sort of log that would show what was going on with the samples as each track was recorded.
Maybe my new Behringer sound card is sloppy, and his bad work ethic has rubbed off on my PC. An audio interface with an atomic clock is too high of a barrier of entry for me, if no one has any ideas that don’t involve buying more things I think I’m just going to try older versions of the app until I find one that works. That might take me a while, I’ll update with what I find when I can.
Super good to know that. That means it’s probably not one simple failure and that’s it. You have something that’s unstable or breaking. All this is happening on one computer, right?
Motherboard problems are pretty rare, but they do happen.
This is where you start paying attention to extenuating circumstances. Does the damage change with time of day? How about heat? Is it worse when it’s hot out?
You have turned the machine off and on, right? Windows has a special process for this. The other two Operating Systems‘s don’t, I think.
Is it worse the longer the show is, or the longer the computer has been on? You see what I’m doing here?Don’t gaze closely at the computer or the recording and ignore everything else.
Can you make it worse? I know the goal is to fix it, but if you can reliably change the effect, that can go a long way to fixing it.
Temperature changes would be my favourite place to start looking. Is whatever does the initial conversion from analogue to digital always at the same constant temperature, and has it had long enough to stabilise if it has come from somewhere warmer or cooler - and don’t forget internally generated heat, so has it been powered up long enough for the internal temperature to stabilise?