I've gathered they play music, [ Strange sighs, as he gestures to the walkman. ] Which is quite useful in it's own way—it saves one time and effort when hiring musicians. But the sound is so quiet! One can listen to music by himself, yes, but music is far more enjoyable at parties! With dancing! Something loud enough for a ball coming from something like this is hardly possible.

[ Speakers, buddy. The electronic device you're looking for is speakers.]