Midi Time Code delay/latency 2 computers. Help Please!

Hi, everyone.
I got Cubase 5 on PC as master and Cubase Elements 8 on MacBook as a slave. I use Midi Time Code (MTC) as a source via rtpMIDI (tried with MIDI cable - same result).
Everything goes well: play, stop, rewind.
I use only metronomes to understand if Cubases are synced well. At first, two metronomes are almost all the time (almost)) synced. Then gap between beeps increases and after 40-60 seconds of playback the gap becomes noticeable enough to make working process impossible. Every time I stop the playback the difference in timing is about 0:00.020.
Dear friends,
what is wrong?))

bump

anyone?

Hello,
Several things to comment on here.

First -

Every time I stop the playback the difference in timing is about 0:00.020

And just to be clear do you mean 2/100 of a second?
Does that mean

  • A - no matter when you stop it it’s always off by that amount or
  • B - after your noted 40-60 seconds it’s off by that amount?
  • C - does it mean it’s in time and when you stop it one system is offset from the other by that amount?
    If A and/or C, the two systems will not stop at the same location because there’s not MMC locate commands being sent. That doesn’t matter they don’t need to stop in the same place, they only need to play at the same speed and same location (more or less).

Second -
The outputs as you noted are “almost” in sync when you start, that’s normal. MTC is surprisingly accurate in Cubase/Nuendo and we typically find no more than approximately 1ms variation between systems when they chase TC and usually less. However that much drift should not be occurring in the length of a song. There will be a small drift because you probably don’t have the audio clocks locked so the systems will play back at slightly different speeds but with decent audio I/O the variation is measured in the ppm range so within 40-60 seconds you should have almost no drift.

  • To help isolate, do you have a way to clock the audio devices the same to eliminate that as a variable?
  • Are you certain both systems are set up identically (frame rate, midi settings, etc.)?
  • Bottom line is you need to isolate why the systems are running at such different speeds because if they’re set up the same (same sample rate, midi settings, frame rate, clocking, etc.) they’ll play very close to the same speed even without audio clocking and better with audio clocking.

See what you can find, there’s something that’s different on the systems.
Hugh

Hello, Hugh! Glad to hear your answer)
I’ve uploaded a short video with my setup and problem.

And just to be clear do you mean 2/100 of a second?

  • Yes.
  • A - no matter when you stop it it’s always off by that amount or

It’s “A” and with the help of your answer I understand the reasons:

because there’s not MMC locate commands being sent

Unfortunately, I can’t have audio clock setup(

  • Are you certain both systems are set up identically (frame rate, midi settings, etc.)?

All project settings in “Project Setup” window are identical. What “Midi Settings” are you talking about? I’m not sure about this point.

One more tip:
When I place Scroll Line position in stop mode to the strict lines, like bars and beats, the Time display shows identical figures in both projects like: 2.1.1.0 or 0:00:02.000, and the same throughout the project. But somewhere in between - figures are different, like 1.1.1.117 and …00.121 in first and 1.1.1.96 and …00.100 (almost 2/100 of a second) in slave project.
FPS is 30, slave says “Lock 30”… Can’t figure it out(
Thank you in advance!

Hugh…? Anyone?

Hello,

Nice video.
I don’t know why, on the locate events after the first one, the slave system locates but not exactly.

I hear the drift on the first play event. I don’t use the metronome nor much midi except to trigger sound efx so I can’t comment on that. Try importing the same audio file to each system and play them - the audio will be slightly out of time but shouldn’t drift much over the length of a normal song. If it does drift significantly then the audio systems are not playing at the same rate. Can you clock them the same?

Hugh