On June 28, 2018 at 10:28, weddellkw said...
What device are all those speaker wires plugged into on bottom right of the rack?
It's a pair of Niles SPK-1 speaker switches that switch rear & back surround speakers from the AVR to an AudioControl amp for Sonos. When the AVR is powered on the 12v triggers activate the speaker switches connecting the surround speakers to the AVRs outputs. When the AVR is powered off, the surround speakers revert back to Sonos.
The inwall subwoofer is powered by an amp in the rack. The audio matrix portion of the AudioControl M4800 amp handles switching the of the line level signal for the subwoofer so it can also be shared between surround & Sonos. DSP in the M4800 handles high & low pass filters for the surrounds & sub when in "Sonos" mode.
