Funny how I realize how little I know about such a simple thing. So my powered monitors have balanced trs and xlr ins and for unbalanced an rca.
The output of my ME-90 is switchable from line to basically a pedal output. What I really want is to be able to use the monitors for just music etc from my desktop, use the monitors (they are powered) for the stereo output of the me 90, and sometimes have them both going at the same time to play along with tracks etc. But I want to have just one set of cables running to the monitors and I want to be able to plug into a mixer (or something easily accessible) so I'm not getting to the back of the monitor (which is on a shelf on both sides of the room) regularly.
If I'm understanding you correctly something like this could work?
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I don't mind the idea of having an actual powered mixer to do this though if there are any advantages to it though.