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View Full Version : MIDI/MTC sync timing issues with N2 (and Logic 7.2)


Scottylad
04-26-2009, 05:59 PM
I attempted to sync Logic's MIDI clock (and MTC) to N2.01 with some odd timing results.

First, though sync was successful and the transport did indeed start when Logic's started, timing was less accurate than I had hoped for. In fact, timing wandered in fractional increments around 120bpm. I MIDI output of N2's sequence to Logic showed that over time the sequence gradually became out of sync. I can watch the clock rate in N2 while this occurs, and see it update in realtime.

On the positive side, N2 (running on the same computer as Logic) kept better time than when receiving sync from Logic. So the only downside is the lack of playhead synchronization.

Another issue that caused me to abandon sync is the issue of delayed playhead reset.

When a sequence is played for numerous bars and then stopped, N2's transport remains at that bar, say 38:3. I then stop Logic's transport while they are still synced. N2 will not see that Logic's transport has returned to 1, since the transport is not actually playing. When Logic is started again, N2's transport takes a moment to sync back to position 1 before it starts playing.

The end result is that not only does the sequence start late, it sometimes misses the first note.

There seems to be no way to turn off sync, reset N2's playhead back to 1, then re-enable sync. Re-enabling it just sets the playhead back to what the position used to be (38 in this case).

It would be helpful if there was a sync override option that would allow you to force the playhead back to 1 regardless of the DAW's last playhead position.

For now I am starting Logic's playhead while unsynced, then starting N2 while recording in Logic. Afterwards I need to edit the region in Logic and shift the notes to the start of the bar.

I understand that there is some MIDI latency involved when sending MIDI data from N2 to the DAW. The biggest issue with sync that I have encountered is not only the additional delay while the playhead resets to the beginning, but the occasional missed or truncated notes when the sequence starts in N2.

An override would be very helpful unless there is another method that I'm not familiar with.

jim
04-26-2009, 06:46 PM
I think most of what you're seeing is likely due to MTC itself, which behaves a bit differently from MIDI Clock, in particular:

- MTC doesn't really have a 'reset' or instant-locate option, so you have to give it some pre-roll to give slaves a chance to chase to the new location.

- MTC doesn't transmit tempo, so you have to make sure both programs have the same tempo set.

My recommendation for now is to actually use MIDI Clock, if you are on 10.5.6 (earlier versions had some bugs in a MIDI sync library I'm using).

Best
Jim

Scottylad
04-29-2009, 09:24 AM
I tried both. I have the "delayed playhead reset" issue with MIDI clock as well. I am on 10.4.11 though, for various reasons. Is there no workaround at present with my OS?

jim
04-29-2009, 09:30 PM
Unfortunately, there's no good workaround for the MIDI clock thing, other
than using MTC. I'll look into the 'reset on sync' issue.

Jim

shamburglar
04-30-2009, 07:26 AM
I got the midi latency in Ableton Live while using midi clock almost perfect by tweaking the midi clock sync delay, is there a similiar option in Logic? On my machine I had to set it to about -38 ms but now everything i play out of numerology almost exactly lines up with the grid... hope this helps... I know Jim recomended a plugin that compensates for midi latency...