Has anyone successfully midi synced their op-1 to a loop pedal using EXT link?

Title says it all. Thought I had figured this out but definitely having issues syncing using EXT mode to rc300 looper. I use a disaster area designs midi usb host.

u may want to elaborate in order to help peeps help u
like what kind of issues are u having?
it is not syncing at all? is it drifting? etc etc

fwiw, i’ve found that op1 works a lot better as master when syncing via midi clock.
sync was kinda iffy the other way around

Thanks. Unfortunately the rc300 can only be master so I’m stuck with the op-1 receiving it’s clock. After further testing it seems the metronome is rock solid. It’s the tape where things are unusable.

If I’m playing a loop on my loop pedal the transport controls from the pedal get sent to start the op-1 tape, which is good. The problem is, if a record anything to the tape while everything is rolling, it will drift.

I also tested the tape with pre-recorded quarter note drum loops. Over the course of a couple minutes, anything recorded to the tape was off beat. Again, the metronome was on beat.

Any idea why the tape would drift while the metronome seems synced?

Maybe a stupid question, but have you synced your tape to your clock/metronome?

Yep, the EXT mode syncs the tape automatically.

I also don’t think it’s a loop pedal issue and is an issue with the OP-1, as the loop pedal syncs with other gear fine.

There are a few factors at play. The first is that the OP1’s CPU is not very fast and with some synth engines it just slows down - usually the graphics suffers first. Another is that accessing its internal memory, especially to write tape tracks, costs it extra cycles too. The loop smoothing algorithm in it (which doesn’t sound great) also spends time. Last but not least, you’ll have noticed that the OP1 doesn’t have much latency, and that means there isn’t much time for error-correction after the fact. These things add up, imperceptibly at first, but if you leave the OP1 to loop or run for a long time, you’ll discover that it drifts out over the course of a few minutes, even with the best of MIDI clocks.

MIDI clock jitter (clock data is frequent), does exist with some many clock signals even before you send them down the USB wire. Oh, and serial MIDI is just very slow to be too precise. And on top of that, USB itself doesn’t have very good timing, and especially with standalone MIDI hosts like legacy iConnectMidi, you can kiss that timing goodbye.

If you look very carefully while the OP1 is running, synced by MIDI in, occasionally you will notice the bar marks on the tape actually shifting left and right, as the new information comes in. The tempo counter is too coarse to tell you that in detail but fairly often the marks move noticeably to the eye (especially in later sections of the tape).

When you think about the track “ticks” (the marks from above) shifting their position, while the OP1 is looping synced, do also keep in mind that the loop points are not defined in bars or beats, but in exact absolute track positions - i.e. samples. In a DAW that would not be the case. It is a subtle difference but enough to make for time drift after a few minutes.

All in all, you might be better off monkey-syncing by just matching the BPM. Or have the OP1 send its clock out (but keep in mind it doesn’t do a much better job at keeping time).

I spent considerable money on an external MIDI clock, only to find that the OP1’s design makes drift inevitable, even with an extremely stable clock.

Perfectly reasonable to ask then “so how does a looper unit that supports midi clock does it so much better?”. I don’t know — I expect a lot of research has gone into audio and tempo smoothing so loopers “just work”.

p.s. the built-in metronome itself is the worst, I think it just starts counting from the moment you press Play but doesn’t respond well to a changing tempo (think clock drift over time), so it just ends up being off really easily.


Great post, thank you. I guess the best bet would be running the op-1 through the loop pedal to get some more functionality.