MIDI beat clock problems

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Level 1

9 points

MIDI beat clock problems

A while ago I started using MainStage as a live multi looper. It works great by itself, but the goal is to use it with other musicians. I’m having problems both sending and receiving MIDI beat clock information.

On the receive side: Upon enabling MIDI in at the concert level, I get rapid tempo fluctuations of about +/- .02 BPM. I’ve tried sending clock signals from an MPK49, Eventide Timefactor, and Maschine. I’ve tried using the MPK49, and a Profire 2626 to receive time clock. We loose sync pretty quickly.

On the send side: Upon creating an external instrument patch, checking “start sending midi clock” “send start message” and “send stop message” results in the same problem on other devices sensitive enough to report the +/- .02 BPM fluctuation. Frustrating! Also, when MainStage is transmitting beat clock there is a signifcant lag before playback begins.

So I guess my question is, how to I get a reliable sync with 1-2 comuters and a handful of DIN/USB MIDI gear?

MacBook Pro (13-inch Early 2011), OS X Mavericks (10.9.1), 4GB RAM, Mainstage 3.0.3

Posted on Mar 2, 2014 11:40 AM

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Answer 1

Blueberry

Level 4

3,087 points

Mar 2, 2014 12:36 PM in response to evanwhite

That feels like an incredibly good number: only +/- 0.02 BPM! Wow. Seriously.

But it seems you try to use this to do a sync that last for a long time. Beat Clock won't do that, there is always gonna be a drift because of clock drift. No chance to solve it just with beat clock!

Getting several devices in-sync and stay in-sync, you might have to look into time code. Search for "word clock", it's a complex setup which I would only recommend in a studio setup, not in a life scenario.

I would try to simplify your setup so that you don't need to sync externally over an extended period of time. Everything else is setup to fail.

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Answer 2

evanwhite Author

Level 1

9 points

Mar 2, 2014 1:19 PM in response to Blueberry

Thanks, Blue. Yeah, the low variance is good and I expect some! What I can’t seem to figure out is why Loopback drifts off time while my outboard gear clocks and the MainStage beat clock stay together. I feel like it has something to do with rounding? (Loopback reports up to a tenth of a decimal, while MainStage up to a hundredth) Or could I missing something in loopback that would at least make loops start on their respective downbeats? I know of MTC and unfortunately can't really make use of it in my application.

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Answer 3

evanwhite Author

Level 1

9 points

Mar 2, 2014 1:40 PM in response to evanwhite

I should clarify. Say for example my Eventide Pitchfactor is sending clock. MainStage reads it, fluctuation included, and beats in sync with the Pitchfactor. The problem is that Loopback and instances of recorded loops eventually float out of time with the MainStage beat clock. Any way to make loops snap to the beat?

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