Using a StudioLive/Mixer as an Interface does have some fundamental differences compared to using a dedicated Interface.
Interfaces, generally speaking, have the option for direct-output routing.
Meaning that in StudioOne you can choose an output channel from the software and audio will output through that assigned output-channel over USB.
No further steps required for output routing.
Consoles/Mixers do not have direct-output routing.
Consoles/Mixers only accept audio to their INPUT channels.
- You could return audio from your StudioOne Mains to Channel 1+2 on your StudioLive. (or any pair of your choice)
- Then, you would turn up the Ch 1/2 faders (set to USB) in whichever output layer you'd like that signal to output. (Main, Auxes, etc.)
Interface Mode for StudioLive Series III:
With firmware 2.4+ for the StudioLive Series III Consoles and Rackmixers can now be put into "Interface Mode" from their Settings menus.
This will rearrange the USB Channel assignments and allow for Direct-Output routing from your DAW to a physical output of the StudioLive without needing to assign signal to an input channel first.
More Information on Interface Mode and the USB assignments can be found here:
Please contact PreSonus Technical Support by creating a Support Ticket at My.PreSonus.com/Support for further assistance.