issue with slowed playback speed

Audacity Help Forum Windows
1

Hello,

I haven’t recorded using Audacity in a few weeks now, but as of trying today I am faced with an odd issue that I haven’t seen before. I will do my best to explain.

Scenario: Record 2 overlapping guitar tracks

Step 1: Record track 1, playback, track 1 sounds fine (DAMN GOOD I might add :mrgreen: ).

(no modifications to any settings whatsoever between steps, just pressing record, play, and stop buttons)

Step 2: Record track 2, playback, track 1 sounds fine underneath, track 2 is exactly 1 full step lower in pitch

Track 2 seems to also be slowed speed-wise proportionately to the amount that the pitch is lowered, although this is hard to pick up on exactly since a “1 second long” note might become 1.1 seconds after recording and I can’t tell if that difference is caused by my own physical inconsistency.

Thinking it might be my computer getting bogged down with a measly 2 tracks (Core i5, SSHD) I added a third, fourth, and fifth track. Every track except for track 1 is an exact full step lower than the original recorded/input pitch.

I’ve tried adjusting the recording and playback quality, ensuring they are equal, etc. Even if a setting is causing the slowed playback, I can’t even imagine how it allows my first track to be recorded and played back fine, but tracks 2+ are dropped by a full step.

One last thing I noted is that it’s not only the playback that is pitched down, as soon as I hit ‘stop recording’ on track 2+, I immediately see it alter the shape of the wave and move it back about 0.1 seconds. The track itself now exists at that lower pitch/speed.

Am I missing a really obvious setting that I accidentally engaged by pressing a secret combination of buttons or something?

2

My brain isn’t completely understanding the symptoms, but…

By any chance are you using different hardware for recording and playback? Sometimes people use a high-quality USB mic or USB interface for recording, but play back on their regular soundcard. If the clocks (oscillators) don’t match*, the playback speed and pitch can be off. The problem gets compounded when you record a 2nd track with the same tempo & speed of the playback of the backing-track, but different from the recording of the backing track, and the two won’t match up.



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  • For example, you’re supposed to be recording at a sample rate of 44.1kHz, but no clock is perfect and no two clocks are exactly the same and some consumer soundcards can be off significantly. (Pros use a very-accurate master clock and interfaces with an external master-clock input.)
3

Also even with the same playback and recording device, the tracks you’re playing must be at the same sample rate (look above the Mute/Solo buttons on each track) as the sample rate you’re recording at (see the Audacity Project Rate at bottom left). It “shouldn’t” matter but with some devices it does.


Gale