What part of no 12v is so incomprehensible? I've never seen a source with a trigger in that price range. And who would want a one source system?
A Tricklestar strip will work. In my experience they are transparent.
Audio signal sensing auto on/off switch
I want to power my sub with external amps (have Behringer and QSC on hand). Both do NOT have a 12V or "signal sensing auto on/off".
I can only find circuit boards from China or Israel, and both take weeks/months.
I would assume that there is some DIY kit or ready to use 'box' available here in the US that offers this basic function. But can't seem to find one.