When I record a vocal, listening to a pre-recorded rhythm track to keep time (using headphones), the vocal gradually gets ahead of the rhythm track. By the end of the song, the recorded vocal is about two beats ahead of the rhythm track. The sample rate is kept at 48k. How can I prevent a recording from speeding up?
One possibility… Are you recording and monitoring on different devices? Like using a USB mic with your headphones plugged into your laptop’s sound card?
The clock (oscillator) that generates the 48KHz sample rate is in the device. They’ll never match perfectly and sometimes they are far-enough off to cause pitch or timing problems.
Yeah, that. Are you using the Overdubbing Feature where Audacity is playing the backing track to you and recording the new voice?
Quick Check. Do a short recording where you lay one headphone on the microphone. Are you super-duper sure one track isn’t at 44.1?
I can’t think of a good way to get a tiny timing offset other than your backing playback machine is trash.
Can you unplug or defeat your network?
Have you ever done a Clean Windows Shutdown? Windows doesn’t close or reset everything during a simple Shutdown or Restart. Hold the Shift Key when you shut down and the machine should clean itself up more thoroughly.
Koz
Describe the backing track playback thoroughly.
Koz
My mic is plugged into a DBX286s, which goes to a Focusrite USB interface then on to my PC. Headphones are plugged into my mixer that is connected to the PC soundcard. I have the buffer set to 2048 to ensure no drop-outs occur. The large buffer causes asynchrony but only after recording: it is uniform and thus easily corrected.
When recording, I play back only the drums and rhythm guitar tracks for timing and pitch; all the other tracks are muted.
Disconnecting the network did not help. Thanks for the tip about a clean shutdown: it seems to have reduced the audio drift as a new recording was only one beat early at the end. All the tracks are sampled at 48K. And yes, I am overdubbing. How else can I keep time?
Try monitoring through Focusrite. There’s a good possibility that the clock in your consumer soundcard is off.
The clock in your consumer soundcard wouldn’t change error by simply restarting the computer.
That points to something in the computer trying to “help you.”
Do you use Skype, Zoom, Meetings, Multi-Player Games or other communication application? They take over your sound services and you don’t have anything to say about it. The problem comes when you leave them running in the background by accident or worse, close them, and their sound services get stuck on.
Clean Shutdown is supposed to clear that. It dumps all applications and programs.
Do you get different symptoms if you Clean Shutdown again? I’m almost out of ideas. There are not a lot of ways to get a wandering timing change.
One more. Create a new backing track that is exactly some duration, say ten minutes. Start the stopwatch on your phone as you start the backing track playing. Go make coffee. Come back in ten minutes. The backing track should be just ending. Is it?
Koz
…And that means Audacity should show 10 minutes. Audacity’s timeline is based on the exact number of samples for 10 minutes at 48,000 samples per second.
I’m on the edge of my seat.
Koz
Thank you, thank you, thank you all. I applied all the suggestions and the issue is resolved. I do not know if which solution fixed the problem…perhaps all. Another thing I tried was mix down a cue track (rhythm guitar, bass and drums) and open it in a new project. Recording the vocal with just the cue track for pitch and timing reference requires less processing; but with the issue resolved, I don’t know if the latter is an option.
Again, thank you all for lending me a hand.
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