Definition: A Passive Radiator is a speaker cone without a magnet or voice coil assembly and not connected to an electrical circuit that is used with an active speaker to improve bass response. Passive radiators are often used instead of a port or vent in a bass reflex speaker to tune the low frequency or bass response of the speaker.
Also Known As: drone speaker or passive cone
Examples:
Some speakers use an active speaker cone combined with a passive radiator speaker cone to improve bass response.