The physics of clocks and file generation

Oblique · 2022-12-15T23:45:15.982Z

At face value this would seem to be yet another ‘clock jitter hardware’ thread… but with a big difference

…or at least I think its a difference - can someone please help me understand this?

Process to reproduce

I program kick drum in Digitakt - 4 on the floor - on the grid
Start resampling the kick track on the Digitakt for 30 sec and save file
Import to daw (using transfer app)
Check BPM matches DAW and sample is not warped!
Align first kick to daw grid
The kick 30 sec later is slightly before or behind the grid (as if the digitakt clock is consistently faster or slower)

Comments

I realise the daw clock is slightly different to the Digitakt hardware clock - but it shouldn’t matter!

It is a 48khz wav file - a grid of numbers where each kick should occur after a certain number of samples - regardless of which digital device opens the file.

It SHOULD align with the daw perfectly.

yet it does not and I don’t understand why

It is the Digitakt’s own clock printing its own wave file

no USB audio interface buffer pipe-line, no drivers, no midi clock sync issues - simple!

If I had hair I would tear it out!

DaveMech · 2022-12-15T23:56:46.935Z

Oblique:

It SHOULD align with the daw perfectly

Well, not necessarily as is the case :). There is a slight difference and this can be as small as 0,005 bpm or even smaller.

Happens in studio one as well. It also happens if you simply record into your daw with both BPMs the same.

Between hardware the same is the case. Just a matter of hardware not being 100% exact probably. I’ve never used midi sync between the xone db4 and Digitakt but they can stay in sync for more than half an hour before starting to phase more obviously. But still not exact.

Doesn’t really matter if you record it within the hardware to a wave file or directly to a daw. The kick is triggered according to DTs clock and thus printed to the wave file as such.

Solution: use overbridge to sync to daw rock solid.

Oblique · 2022-12-16T00:04:45.999Z

Thanks Dave! I think your explanation about when the kick is triggered (by the DT) into the wave grid - makes sense

I do use Overbridge and I do like it

Oblique · 2022-12-16T00:34:34.742Z

Next question - do you ever use Ableton’s audio quantize (or similar) for situations like this? can it be done while preserving transients? (eg for drums)