I’ve been configuring a new audio workstation, and I found that my Reason and Sibelius ReWire audio inputs wouldn’t work in MOTU Digital Performer 7 like they do on our other workstation. I spent the first part of 4 hours trying to decipher whether the problem was with Sibelius’ config or DP’s, only to remember that I hadn’t yet disabled Ableton Live’s ReWire client mode and inputs for this new workstation.

I’m not sure the problem is necessarily with Live, but perhaps with DP having to handle so many ReWire inputs – maybe DP (or ReWire) has a 128 channel limit? At least on Snow Leopard 10.6.2 with Digital Performer 7.02 and Live 8.1.1, DP couldn’t handle adding Live’s additional 64 inputs to my existing 64 Reason inputs, 2 Sibelius inputs, and 2 Waves inputs. Note: the Live inputs were not even assigned to a DP input. (In Bundles, no rows and no chicklets). Just having Live’s inputs available in DP prevented both Reason and Sibelius from passing ReWire audio into DP.

I generally use Live as a standalone DAW, so I don’t need access to these ReWire inputs in DP. But it’s not very obvious how to disable them, and it took me the rest of the 4 hours trying to get DP to forget about Live’s ReWire channels. Turns out it’s stupid-simple. Add one preference in Live’s Options.txt file and then delete two aliases from two different Mac OS X Library folders.

NOTE: Doing the steps below prevents Live from becoming a ReWire client mode for all apps. It also completely removes the inputs from Digital Performer’s Bundles > Instruments window. I don’t know what else it might do – proceed at your own risk. :)

To disable Ableton Live’s ReWire client mode and remove the inputs in MOTU Digital Performer:

1. Quit both DP and Live if either are open.
2. Edit (or create) your current “Options.txt” file for Live, according to Ableton’s FAQ page. Add the (undocumented) flag -ReWireSlaveOff. Setting this flag tells Live not to undo what you are going to do in step 4.
3. Save and close Options.txt.
4. Navigate to /Library/Application Support/ (that is, your top-level Library folder) and trash the alias named “Ableton Live Engine.bundle”.
5. Navigate to ~/Library/Application Support/ (this one is the Library in your Home folder) and do the same thing to that “Ableton Live Engine.bundle” alias.
6. Empty the trash for good measure.
7. Relaunch DP and verify that the Ableton Live channels are gone from the Bundles > Instruments tab.

DP’s Instrument Bundles have been a little fickle since v6, so this all may be the result of some bug in DP. Or am I hitting some limitation of ReWire 1.7, or is it something in Live’s implementation of ReWire. It is curious that every other audio app I have besides Live places a .bundle file in /Library/Application Support/Propellerhead Software/ReWire/ to register their outputs.

Why does Live place a lonely alias at the top-level of Application Support? Why isn’t the file named “ReWire” like other companies do? Maybe that “Ableton Live Engine.bundle” alias does more than just publish ReWire outputs. But Live reinstates the alias only when the -ReWireSlaveOff flag is gone from Options.txt. So as long as Live doesn’t repair the alias when -ReWireSlaveOff is present, I’d say we’re safe.

What originally started as a quest to fix broken ReWire audio between Sibelius and DP became instead about how DP and Live work together (or don’t).

Deleting Live’s ReWire inputs from Digital Performer restored ReWire audio from Sibelius and Reason both. I hope that saves you some time.