well, took a quick look at jack, and it looks like you're right, adding AU support to SC would be redundant. but jack only does audio, but not control. midi would probably be enough for control (although "automatable" parameters from the host would be nice). does interapplication midi already exist as well in another app? this isn't built-in to core services, is it?
it would be quite useful to have a VST or AU or LADSPA unit that outputs silence but sends OSC messages. this would allow to control SC from other applications like FinalCut or Protools.
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