Sandpiper, yes - FX-Teleport. The *exclusive* announcement. [:D] [:D] [:D] [:D] [:D] [:D] [:D] [:D] [:D]
JBM - I got rid of my digital mixer a couple of years ago and haven't missed it once - even though it was a really nice board (Panasonic DA7). It had been sitting off to the side untouched for years with the faders at unity, doing exactly what my MOTU hardware does: submixing synth outputs.
The difference is that you don't need to submix them if you have MOTU (or other) hardware, which is less expensive, has enough digital inputs to accommodate all my computers and a couple of hardware instruments I still use (I would have had to add a second mixer to handle everything), and doesn't require you to submix anything - all the inputs come up in the DAW's mixer.
Digital mixers are for people who record live ensembles and need all the mic preamps, talkback features, and quick access to input channels. They're also for people who like to mix on mixers.
But I'm much happier with the streamlined set-up. I got rid of all the extra outboard crap and now just have two high quality input channels. Oh, and I also added a monitor controller (Blue Sky BMC) with a remote sits on my desk; it has some features that are much more convenient than the mixer's monitor section, and I love having it right there within reach.
So if you have a reason to have a digital mixer, of course that's good advice. But it's totally unncecessary if you're just streaming slave computers into your DAW.
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I'd forgotten that the Mac MINI has digital outputs, but those would work fine...if you only have one computer (and of course if you're happy with just two outputs). If you have multiple machines, there's no way of synchronizing their digital clocks - they don't have digital input. By the time you rig a system to handle asynchronous clocks (i.e. that do a small sample rate conversion to keep everything in sync), you're looking at bigger investment than just getting FireWire boxes...that are a better solution anyway.