MOTU for live digital playback

[audiodavid1]

Hey all,

I'm looking for advice on using my MOTU units for 8 tracks of digital playback in a live band situation.

I'm using 2 MAC minis 1.83 Ghz 1Gb RAM w/external firewire hard drive. I'm running Digital Performer 5.12. One unit is for primary and the other will be a redundant backup. I'm running the primary unit through a MOTU 828MKII USB 2.0, from there the outputs are sent to the A side of a Radial SW8 A/B switch to cover the redundancy issue. The backup unit will run on an 828MKI yes MKI. The output will run to the B side of the A/B switch unit.

The units will be controlled through MIDI with an Oxygen 8 MIDI keyboard. The MIDI signal from the keyboard will be sent to a 2X2 splitter where it will go to each MOTU unit. The keyboard resides with the drummer to control the song flow. There will be an additional unit near me for emergencies.

Here's the question...

How do I make sure the units are synced during their playback? The units are not really talking to each other, only receiving MIDI instructions from the controller. I'm finding the units will not run the same exact speed. That pretty much mutes the redundancy which is key to this system. I'm using the word clock of the primary unit and slaving to the backup unit.

Anybody mess with stuff like this?