Bookburn writes –

“A what?” you ask. An “electromechanical transducer” refers to the type of speakers we are most familiar with; a permanent magnet and an electromagnet wildly vibrating to produce sound. And by “polystyrene conical section” I mean plastic cup.

Whatever this is, it is not an Instructable on how to callously rip apart your roommate’s computer speaker and glue the driver into some other object. I show how to build the actual transducer unit (commonly called a speaker driver) with a few simple objects. The speaker is super easy, extremely impressive, and so cool that it even makes Kenny G. sound good.

Electromechanical transducer out of a polystyrene conical section – Link.