Looper getting out of sync even with MIDI control?

[Johnnyhell666]

Hey there guys, 

 

My entire band is running on Helix and we have an Ableton session switching all our presets automatically with MIDI commands. Everything works great so we started to use the helix loopers as well (MIDI command to start the recording and to stop it etc.) 

It's working great the only problem is that it randomly just doesn't work sometimes. Sometimes there's absolutely no issues with it and sometimes the loop eventually goes out of time. I'm just wondering how it's technically possible that it goes out of sync when the record button is actioned by MIDI on the grid and so is the playback one - so technically it should just be perfectly on time every time having been digitally recorded from point A to B on the grid. 

 

We've had some success trying to compensate the Driver Error Compensation (compensates the output latency depending on the buffer size), could that be the explanation? 

Also, sometimes the "Once" feature on the looper just doesn't kick off either. We were trying to bypass this issue by simply putting a few "once" MIDI commands throughout the session so it would start perfectly on the grid everytime, but sometimes the command just doesn't work. It's really random. 

 

Anyone has an idea of why we're having issues (only sometimes)? 

Thanks for your time! 
 

[PierM]

You need a clock, and Helix looper doesnt respond nor generate any clock or sync pulse.

 

You are just sending midi commands, which isnt enough to keep things in sync.

 

[Johnnyhell666]

On 1/3/2023 at 4:16 PM, PierM said:

You need a clock, and Helix looper doesnt respond nor generate any clock or sync pulse.

 

You are just sending midi commands, which isnt enough to keep things in sync.

 

 

I'm just having a hard time understand how two MIDI commands which are sent perfectly on a grid from a computer session makes it get ouf of sync eventually. I mean it's not like you can be more precise than this, right? 
 

Not to mention we've had success with it, it's just really random. Sometimes it choses not to work. 

[PierM]

That's why clock and sync pulse exists; you dont just need to send a start command (that can drift depending on latency, buffers, jitter, dpc etc etc), but also how match the tempo of the master clock (through regular pulses timed as fraction of the BPM), and also stop commands.

 

Even clocked loopers can drift as MIDI clock does suffer from heavy midi traffic, so unless it's just a clock being sent, even a wired clock couldnt be enough to keep things in sync.

 

Usually you find this feature on high end loopers, but again, isnt a bullet proof system. Helix just doesnt respond to MIDI Sync so you cant do it.

 

The only looper that I managed to have respecting clock and stay in sync forever without drifting, is the Echoplex Digital Pro Plus....yep, a 30 years old piece of gear.

[PierM]

This could help you understanding how it works;