just bought an Ultralite mk3... I want to use the S/PDIF output to feed my ERGO(KRK). I set the routing in Ableton Live 8.0.1, running Windows XP Pro SP3, as following:
1/2 -> Outputs 1/2 are reproducing the sound.
3/4 -> Outputs 3/4 are reproducing the sound.
5/6 -> Outputs 5/6 are reproducing the sound.
7/8 -> Outs 7/8 are reproducing the sound.
9/10 -> Headphones are reproducing the sound.
11/12 -> Strange: The Main outputs are reproducing a horrible sound (like unmatching samplerates).
13/14 -> The Main outputs are reproducing the sound.
Where is my S/PDIF output? I tried almost everything (driver reinstallation, registry cleaning, etc....)
Normally Ableton counts the outputs of the MOTU devices like this:
Headphones use outputs 1-2
Analog 1-8 are output to ports 3-10
The Main Outs are ports 11 and 12
S/PDIF uses outputs 13 and 14
Btw: I also have a Traveler mk3 here... Everything is functionally as expected when I connect the Traveler...

After all these troubles (countless ours and days) and without a expedient hint from tech support (ableton and motu) I will return both of the devices...Also disgusting: The Motu driver produces almost 2000 registry entries.
Maybe RME has got something suitable...

