With "odd" time signature 6/8, clicks are not perfectly in sync with BB drums

I often want to start playing guitar without drums, and I want drums to kick in later, so I “start” the BB (to make it send START command via MIDI, so that Aeros will keep in sync, but it does not start recording automatically), then I pause BB (which is a “mute” pause), then I start recording on Aeros, and when I want drums to kick in, I do the fill on BB or just unpause it. So while I’m recording the loop without drums, I’m relying on clicks which Aeros generates.

I was always bothered by my loop not being perfectly in sync with the drums. For some time I was trying to think that it’s just my playing being sloppy, but today I actually did some testing, and indeed, on time signature 6/8, on 60bpm, clicks are off by 20-45ms! (comparing to drums from BB). Take a look at the screenshots:

Left channel (above) is BB, Right channel (below) is clicks from Aeros:

So Aeros generates the click a bit earlier than BB generates a drum hit. If we measure the difference, it’s from ~25 ms:

image

To even 40+ ms sometimes:

image

It’s pretty annoying, it’s enough to make people hear that the loop isn’t really in sync. I’m actually not exactly sure whether it’s a problem with BB or Aeros, but those two clearly disagree on something.

Interestingly enough, things are fine on the signature 4/4, clicks are at most a few milliseconds off, I personally don’t hear it. But on 6/8, it’s really bad.

For what it’s worth, also attaching the mp3 file from which those pictures were taken: clicks_6-8.zip (forum doesn’t allow to attach mp3 so I had to zip it)

I was using 60 bpm for those pictures; on lower bpms (like 40bpm) the problem is even more obvious.

To reproduce:

  • Make sure Aeros generates clicks all time
  • On BB, set tempo to 40 bpm
  • On BB (assuming the standard SD card content), select “Odd Time / Odd Time 3 - 6/8”
  • On Aeros, create a new song, set the time signature 6/8
  • Start BB, to make in send START command via MIDI. If Aeros is set to record automatically, it’ll start recording and generate clicks; on this bpm you’ll be able to hear that clicks aren’t in sync with the drums.

BB firmware 3.8.0, Aeros firmware 2.15.5.

Would you please look into it?

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Hey there, thank you very much for this in-depth look, we will most definitely be finding ways to make 0 latency on these clicks, this should not happen. I have reported this to our R&D and we will definitely be looking to solve this problem ASAP.

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Thanks @BrennanSingularSound , appreciate that response.

Just to add some more info: today I also did some experiments on 40bpm and routing clicks to AUX (with the same time signature 6/8), and the difference between clicks and drums is sometimes more than 100 ms:

image

Also sometimes the clicks aren’t monotonic. On 40bpm a measure takes 4500 ms, and since we have 6 beats per measure, the delay between beats should be 750ms. And take a look at those adjacent 3 clicks: the delay between first and second is 690ms:

But between second and third there is 753ms:

Would be great to see the MIDI clock messages (which BB sends) along with those waveforms on a single timeline, but that’s a bit more challenging for me to set up, so I hope you guys can do that.

I’m glad that your R&D team is going to look at it, please keep us posted.

Appreciate all this, thank you.