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Sync with variable speed / slaving [transport] to a clock

Oct 08 2012 | 4:58 pm

Hi – I spent about 3 hours searching the forum (expecting this was something that has been done before) – if you could point me to an existing discussion that would be great too!

I’m looking to synchronise applications, laptops etc with a clock – but with the possibility of changing the clock speed, and possibly location. Pretty much what the transport function does but I’m struggling figuring out how a ‘transport’ object can be slaved.

My initial thought was to send midi clock over OSC. Or MTC over OSC, not sure.

So imagine 2 devices running their own ‘transport’
I can see how I can send a ‘tempo’ and a ‘start’ and a ‘stop’ to the slave transport – but not sure if there is a chance of drift between the the master and the slave (is that likely?) and secondly not sure if I can fluidly changed the speed on the master and how the slave will follow.

On a related note – how do I slave a transport to midi clock?

Oct 08 2012 | 9:19 pm

I’ve synced different computers with OSC (tempo/start/stop) and didn’t notice any drift during a run of about 30 minutes, but without tempo changes. I think that tempo changes are problematic due to message delay.

For slaving to midi clock the [sync~] object can be used.

Oct 09 2012 | 5:19 pm

Thanks broc! Can the sync~ then control a transport?

Oct 09 2012 | 7:28 pm

Yes, sync~ reports start (250), stop (252) and current tempo. For details see ref page.

Oct 10 2012 | 1:06 pm

ah now i get it – I thought [transport] generated a clock, like an advanced [metro] but it actually needs to be driven. Thanks broc!

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Forums > MaxMSP