Loudspeaker

The Daleks used a loudspeaker system. (TV: Mission to the Unknown, The Daleks' Master Plan)
A Cyberman chest unit contained a small hidden "chest unit loudspeaker" which allowed them to receive audio communications. (TV: The Moonbase/PROSE: Doctor Who and the Cybermen)
== Behind the scenes ==
According to NOTVALID: How The Monk Got His Habit, which is not accepted as a valid source for in-universe articles on this wiki, a woofer was a type of loudspeaker used to render low frequencies more accurately.
Category:Communications technology from the real world
Category:Dalek technology
Category:Cyber-technology