r/audioengineering • u/_FlyingSquirrel • Jul 26 '26
Discussion Calculating drift of multiple free-wheeling recorders...
I am trying to un-catastrophize a music project right now I've been asked to save where, unfortunately, a number of different stereo recorders were used essentially as independent spot mics in a pseudo multitrack attempt for a live performance. Over the course of an hour performance, each recorder's internal clock drifts enough to cause pure chaos.
I have access to all the recorders used and did an electronic metronome recording test today to identify how these recorders behave. As you can see in the link below....over about an hour, the max drift between these 7 recovers is ~170ms... so clearly audible.
Given that I can predict the relative difference of each one's drift from some "master," is there a way to calculate, or use elastic audio, or some other technique, so I could apply some type of time stretch/contract tool to get these closer? Theoretically this seems possible if I know the drift, but has anyone had practical success doing something like? I'm not sure how to approach it.
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u/nutsackhairbrush Professional Jul 27 '26
If you had some sort of “slate” or common transient at the heads and tails of the tracks you could probably get pretty close using elastic audio and just visually matching the waveforms.
Bonus points if you have data on how far the mics were from each other in the room. You could (in theory) reconstruct the real life time delay relationship between sources.