Bug: Automation delay when recording an external synth sequenced by a MIDI track

[Lewis Dixon]

I can only assume this is a bug, as ive tested it in every way possible, an no-one else seems to have a solution.
Automation lanes sending MIDI CC to external gear are delayed ONLY when recording a sequence to an audio track. So, for example, I have a midi sequence sequencing a MODX, in addition to this, I have an automation lane controlling filter cutoff. If I monitor the audio track the MODX outputs to and hit play, everything is in time, the filter opens when i want it to, HOWEVER, if I then proceed to arm the audio track to record, then hit 'R' to start playback recording, the automation is late, delayed by about 1 or 2 bars (at 128 bpm).

I have also included an image for reference to explain what I mean:

using the image as reference, the red lane is the filter cutoff for the midi sequence (green notes). If the audio track for the external synth is monitored, and simply 'play' in cakewalk is hit, the gear is sequenced perfectly, that curve is at that exact point, HOWEVER, should the audio track then be armed for recording, and recording started using the midi sequence, the automation is sent late, approximately where I have marked.
Ill include an example of the 'late' automation:

late_automation.mp3

Combined with this image, you should be able to hear the difference between when the automation is sending, and when it should actually be sent. the filter should open up BEFORE the lead starts playing, as sequenced (and which it does do if you simply hit play and monitor the audio), however, it doesn't, as can be heard, it opens AFTER the lead starts, which is later than it is sequenced. This ONLY happens when recording the audio from the external synth when sequencing it from cakewalk.

I have checked everything, timing offsets, buffer sizes, nothing is wrong, I even looked at the midi events cakewalk is sending, and the times for the start and end of curves etc... for envelopes are sent at exactly the right time (though, I was using the cakewalk event viewer). This is also not exclusive to just my MODX, every synth I have ever sequenced with cakewalk has experienced this. I have tried multiple different audio drivers, including those for the interface in the MODX, with no change.

EDIT:
So after some digging around, it turns out this happens ONLY when a count in for recording is set, this suggests to me its unintentional, and certainly a bug, but should also be a quick and easy fix.

Edited February 2, 2021 by Lewis Dixon

[JoseC]

Have you tried recording the audio without a metronome count in? It may sound crazy, but might make a difference. I was having sync problems while recording to audio external synths with the midi already recorded, until I found out that everything was fine if there was no count in. Of course it was not needed, but I had it enabled by default and somehow it was throwing things out of sync if on. Worth a try, I guess.

[Lewis Dixon]

14 hours ago, JoseC said:

Have you tried recording the audio without a metronome count in? It may sound crazy, but might make a difference. I was having sync problems while recording to audio external synths with the midi already recorded, until I found out that everything was fine if there was no count in. Of course it was not needed, but I had it enabled by default and somehow it was throwing things out of sync if on. Worth a try, I guess.

i actually did, and it fixed it.

No idea why a metronome count in  causes this, i would still say this is a bug, since i now know when it occurs, and i cant see any logical reason for it occurring. 
This is a pain now, so i have to faff about without countins now for recording, though, its less of a pain than out of time automation.

[JoseC]

1 hour ago, Lewis Dixon said:

i actually did, and it fixed it.

No idea why a metronome count in  causes this, i would still say this is a bug, since i now know when it occurs, and i cant see any logical reason for it occurring. 
This is a pain now, so i have to faff about without countins now for recording, though, its less of a pain than out of time automation.

Glad to hear that. I went crazy until I found out. In my case, It was recording the synth´s audio too early, cutting the first transient. This only happens when you are recording an external synth using an already recorded midi track. Since a count in, or even the metronome, is not needed for that, it is not much of a problem, but it is a sneaky one. I haven´t found any other situation where this matters.