loudspeaker system; PA system
Refers to installed sound amplification equipment in venues, schools, or public spaces.
The gymnasium's PA system was renewed.
スピーカー refers to a single speaker unit, while 拡声設備 is the whole system including amplifiers and microphones.
マイク is a microphone, a component of a 拡声設備.
Compound of 拡声 (sound amplification) and 設備 (equipment, facilities).