My BCD-3 is mounted on a 3/4 ply shelf in a heavy furniture cabinet.
Listening to treble, mid bass and bass response via the speakers, then with a pair of Sennheiser cans (amplifier off) made no appreciable difference. IOW, the Spinner wasn't affected by resonance induced by the speakers.
Disclaimer: Classicalmusic only, no heavy metal or synthesized music.