MTC question

[Guest]

I'm using MTC out of a Yamaha AW4416 to slave pro tools. I also want to slave an Akai MPC. Rather than disconnecting cables, would one of those cheap midi 1in-to-2out cable splitters work? I assume the MPC and Pro Tools would see the duplicated output MTC and sync accordingly and both could sync at the same time?

[Eddy Deegan]

It would probably work to some extent, assuming the splitter supports MTC, but you're not going to get true synchronisation doing it that way due to the tiny drifts accumulating between the two destination devices.

MTC is much like SMPTE in that it only contains timing information in terms of hours, minutes, seconds and frames. Thus it doesn't have any specific correlation to beats/bars other than through mathematical calculations based on the time signature and the accuracy of the internal clock on the receiving device(s). This isn't synchronisation in any real sense due to the differences in internal clocks, many of which differ from others noticeably within anything from a few seconds to a few minutes of playback.

That said, it's worth trying. The drifts may be acceptable. If forced to use MTC the best solution, if possible, is to have the DAW as the clock source and send that signal for other devices to lock to. You may still get drift however, due to those devices independently converting hours/minutes/seconds/frames to locations in the playback timeline.

If you're able to, SPP is better for MIDI sync as it references musical time in 16th notes (converted to bars/beats internally on the receiving devices) as opposed to realtime (converted from hours, minutes, seconds etc).

[James Perrett]

I've just noticed that the AW4416 has a word clock connection so it would be a good idea to run a word clock connection from the AW4416 to Protools in order to ensure that they are both running at the same speed. This should get over many of the issues that Eddy mentions.

If the MPC is only playing short samples then word clock isn't so important as the samples won't drift much over a few seconds.

[Guest]

Thanks guys, I've been dropping audio to and from AW/Pro Tools using MTC for editing via spdif, no issues with sync but is Midi clock considered better then? AW does that too. No problem to join them via wordclock, I'm just not experiencing any issues with sync, just want the MPC One to sync to the AW too without unplugging cables.

[James Perrett]

SPDIF is acting as word clock so, if you can continue to use it, there's no need for an additional word clock connection. I don't think that Midi Clock is better than MTC in this case provided the software that you are using is properly coded and that everything is clocked to the AW SPDIF signal.