Need help resolving MIDI Clock Jitter

[ryanmoda]

Hi,
I am an engineer working on adding MIDI clock synchronization functionality to some effect devices. I am using Logic Pro (10.3.3) to output MIDI clock from my M-Audio Profire610's MIDI Out port.

This in itself is "working", but I notice that the MIDI clock messages are not perfectly consistent. With a BPM of 120, the timing between the clock messages varies between 20.667 and 21.039 milliseconds (ideally they would be 20.833 ms for this BPM, I believe). This in turn causes timing issues with the devices I am developing. Although I'm not entirely sure it's the fault of the clock or my device's firmware

Is this amount of jitter (I believe that's the term) usually acceptable in MIDI clocks?
And if not, would my situation be improved with some combination of Expert Sleepers modules? If so, which ones? If they can help, I'd be one happy customer..

Thank you!

[ryanmoda]

Would a combination of the ES-40 and ESX-8MD perform better?

[os]

Is this amount of jitter (I believe that's the term) usually acceptable in MIDI clocks?

It's certainly common. Some (most?) people would find it acceptable. But others don't, hence products like the Expert Sleepers ones.

Any of the audio-based products (e.g. ESX-8MD, USAMO) should give you a MIDI clock with timing variation of the order of an audio sample (at 48kHz, 21us).

[ryanmoda]

Any of the audio-based products (e.g. ESX-8MD, USAMO) should give you a MIDI clock with timing variation of the order of an audio sample (at 48kHz, 21us).

Great, thank you for the information. I'll look into those.

[justin3am]

I am an engineer working on adding MIDI clock synchronization functionality to some effect devices. I am using Logic Pro (10.3.3) to output MIDI clock from my M-Audio Profire610's MIDI Out port.

I used to work in QA at M-Audio... among other things I tested accuracy of MIDI timing. The MIDI I/O on the firewire devices was particularly bad in that regard. The stand alone MIDI interfaces (MIDISport series) weren't as bad but anything that did audio in addition to MIDI had pretty bad jitter and latency.

In my Studio, I use a lot of Expert Sleepers stuff and I can attest to USAMO and ESX-8MD being much more accurate. I have also had good luck with ethernet based MIDI interfaces.

[ryanmoda]

I used to work in QA at M-Audio... among other things I tested accuracy of MIDI timing. The MIDI I/O on the firewire devices was particularly bad in that regard. The stand alone MIDI interfaces (MIDISport series) weren't as bad but anything that did audio in addition to MIDI had pretty bad jitter and latency.

In my Studio, I use a lot of Expert Sleepers stuff and I can attest to USAMO and ESX-8MD being much more accurate. I have also had good luck with ethernet based MIDI interfaces.

That's an interesting perspective. I'm looking at those two modules in particular; I'm excited to try them out.