What does OT + A4 + AR + OB + Live equal to?

Hello.
I have been exploring the Trinity of OT, A4, and AR for a year or so now and would like to take the plunge into Live running Overbridge. I am ready to spend on a new MacBook pro to complete my set up but I have some questions:
How do I sync Octatrack into this set up? Do I require an external MIDI clock? What I would like is the ability to sync all these machines with Live. I am running the audio from OT, A4, and AR into an Allen and Heath DB4 on 3 channels and I’d like to have my computer running Live + Overbridge on the 4th channel.
Currently Octatrack is the master and A4 and AR are slaved.
Any advise on how to make my proposed set-up work would be greatly appreciated.
Thanks

I would probably slave everything to Live via Overbridge, and connect Midi Thru to OT Midi In from one of the Analog machines synced to Live.

It basically doesn’t work…this was the first thing I tried and Octatrack is lagging
Plus the OB sync is a bit crap, there is an obvious lag in my system…by a little, but enough to fuck with the groove of things

Thanks for the replies. So Basically will I need an external MIDI clock to sync my devices is that right?

I can’t speak to the OT concern as I don’t have one, but I would hold off on pulling the trigger on an external sync set up at least until you get your MacBook and try OB. I think what’s going on in general at this point is that OB, in its relative infancy, is very system dependent. I hear a lot of people saying that the usb sync sucks and initially thought so as well. It was way off on my duo core 2009 Mac mini. But when I upgraded to a 2012 quad i7, it’s essentially perfect. WAY better than live’s midi sync.

Of course it could be that somehow running midi out from one of your OB synced boxes doesn’t work well for some reason…but perhaps it will. The external midi clock systems are expensive; you may not need one!