Receivers and amplifiers are the engine room of installed audio: the amplifiers that drive ceiling and wall speakers in offices, classrooms, and public spaces, mixer-amplifiers that combine sources for paging and program audio, and the receivers that anchor presentation and media rooms.
Power and speaker topology drive the choice. Distributed systems that feed many ceiling speakers are engineered differently from the systems that drive a few room speakers, and matching the amplifier to the speaker wiring scheme is the first design decision, not a detail. Count sources and zones honestly - paging over program audio, separate volume by area, and microphone inputs are amplifier features that are cheap to specify and disruptive to retrofit. For installations, plan the amplifier with the speaker layout as one system. COLAMCO quotes amplification with speakers and sources for business, government, and education facilities, from single rooms to building-wide paging.