Getting direct I/O to work with Pro Tools is, like many things, just a matter of pushing the right button. “I have a Mac with a Digidesign Pro Tools 24 system installed. I want to use Digital Performer’s built in I/O support for my Digi hardware but I keep getting an error message when I try to select direct I/O. Any ideas?”
You probably have multiple drivers trying to access your Digidesign hardware. Check to see whether you have Digidesign Sound Manager Driver selected as the output in the Sound Control Panel. If so, switch to “Built-in”, and that should fix your problem. The Digidesign Sound Manager driver’s purpose is to allow you to be able to route your normal Mac audio out through the Digi hardware (a handy feature sometimes). Problem is when it is configured this way MAS (MOTU Audio System) can’t get to it. The whole idea of their direct I/O is that they have direct access to the Digi hardware. The driver connecting the Mac audio to the Digi hardware is interrupting this path. In order for Digital Performer to be able to get direct access to the Digi hardware your Mac needs to be routing its own audio out through the Apple built in hardware. This means your Mac sound can’t be routed out of Pro Tools while you are using direct I/O from Digital Performer. Well, we can’t have everything, right?
In these modern times of software based systems understanding signal flow takes on a new and often less intuitive character. Nevertheless understanding where and why audio gets routed within your software is just as important as understanding where and why the black wires get run on the outside. Welcome to the era of the modern DAW.