Slicer sync drift with PlayThru

[destroy-with-science]

I'm experiencing serious tempo drift with the slicer with threshold slicing + playthru + sync engaged. Even when specifying an exact beat count, it still will drift. This only seems to happen after the blackbox tempo is set to a value greater than the sample bpm - if it is lower, no drifting seems to occur.

To reproduce:

- load a drum loop sample into a slot on the blackbox
- set mode to slice
- slice drums using Scan (threshold 25%)
- set PlayThru to ON
- set sync to ON
- set Loop Mode to on (optional, but easier to hear drift)
- set tempo to a higher value than the original sample
- trigger the sample and witness the drift

Using version 1.6.5

Hopefully this is enough information to reproduce and fix the bug, happy to provide a video demo or project file if this helps

[destroy-with-science]

Anyone else able to reproduce?

[Aaron]

Thanks for bringing this to our attention. I know Steve has been able to reproduce it.

[Michal Ho]

I have also encountered drift with looped slices, triggered by the sequencer.
These slices were based on grid slicing and precise beat counts, not threshold.
So I assume there must be something wrong with how the slices are looped (maybe an incorrect floating point conversion).
I currently can't confirm that higher or lower relative tempo makes any difference.
I first noticed this behaviour in 1.4, still present in 1.6.5.

[RMG___]

I'm running into this problem. It's really noticeable in my case, especially with higher slice counts. Sample sounds out of time, but is fine in one-shot mode
edit: I'm not using sync by the way- just triggering both samples at the same time, one sliced (128 slices) one not- strong drift occurs

[Michal Ho]

I'm running into this problem. It's really noticeable in my case, especially with higher slice counts. Sample sounds out of time, but is fine in one-shot mode
edit: I'm not using sync by the way- just triggering both samples at the same time, one sliced (128 slices) one not- strong drift occurs

This would support the hypothesis that slice length is being rounded (down?) somehow, every slice seems to lose a few samples. I'm only speculating!

[RMG___]

I guess if PlayThru works by playing the next slice after the current one, any small errors in timing will compound into noticeable ones as more slices play. Or maybe there is some crossfading going on which ordinarily would eliminate clicks but is unnecessary when the start of the new sample is identical to the end of the last one. If its an issue like those, a solution could be that the sample is played normally as if the current slice marker is just used as the 'start' marker of the sample. I'm no audio programmer though so maybe I'm completely off the mark

[RMG___]

Aaron I know this bug has been reproduced but I wanted to make an example in case it helps in any way. The video shows that as soon as the bb hits lots of slices the playback speeds up (or lots of small skips are happening), suggesting that not all of each slice is being played:

https://www.youtube.com/watch?v=p7zxn5-O5GM

the preset is too big to upload to the forum, here is a dropbox link:

https://www.dropbox.com/s/6njb60u0f2...ESYNC.zip?dl=0

in addition to the video, I find if I pitch up the sliced sample (eg, 4 semitones) it does not play through the whole sample with PlayThru but mid way loops back to the start of the file, even though loop is not enabled

[Michal Ho]

This demonstrates the problem quite well, I think.

[destroy-with-science]

Just tested playing a sliced loop with SYNC enabled with 1.7.1, and still not working correctly.

If the project tempo is less than the sample tempo, sync is perfect, but if greater, the sample does not play in time correctly.

I know this wasn't mentioned in the change log, but it was worth hoping for

[zerocopter]

Same here on 1.7.3.

I can observe the sync drift when I do the following:
1. I record e.g. an 8 bar loop to a clip --> loop in clip mode is replayed perfect in sync
2. I change the mode from clip mode to slicer mode and slice the loop with the "Grid" setting e.g. to 8 slices
3. In the PADS setting I set the
LaunchMode to Toggle
LoopMode to On
QuantSize to 1 bar
BeatCount to Auto
Sync to On
Slice to 1
SliceSeq to None
PlayThru to Off
4. When now toggle the Pad with the sliced sample, the first slice (thus the first bar of the recorded loop) is played and looped correctly. However, after keeping it played for some seconds, the loop of the first slice gets out of sync and drifts away considerably.

I really hope this bug gets fixed soon! Hopefully within the 1.7 realease version?
Thanks in advance!

[Michal Ho]

The problem persists in 1.7.3.