This stack of professional audio gear features several components commonly used for live sound reinforcement
The two main black units are Crest Audio CA20 professional power amplifiers, known for high-output performance in touring or fixed installations. Also includedes EV P-6300 mid amplifier.
The blue-fronted unit appears to be a dbx DriveRack loudspeaker management system, used for tuning and protecting speaker systems.
Also included are a wireless microphone receiver, a power sequencer for managing power-on order, Yamaha MG 16 console mixer and a patch panel for audio connections