do_action( 'riff_below_turntable' )

Fires in the place under the turntable, for what a plugin shows beside the record. Print one element for each thing: the place takes room only while one that isn't hidden is in it, and only where the turntable is the view. The record is out when #riff has data-riff-deck="out". Script it from there; window.riff.analyser() hears the music.