[LAU] How to reduce bass in the building

[Philipp]

Hi there,
I need to reduce the loudness in every room except the one with
speakers. The issue seems to be mainly bass frequencies, which is hardly
a surprise. Physically decoupling the speakers from the walls would be
the most appropriate solution in this specific case. Currently some
speakers hang while some sit on wall-mounted boards.

What's the best but still reasonably easy/cheap way to decouple the
speakers?

My guesses so far:
a) hanging is better than wall-mounted boards
b) decoupling actually helps, at least a bit

TIA for any comments

Regards,
Philipp