As an aside, what kind of floor and walls do you have?

In America, many homes have concrete slabs and walls are drywall mounted on wood frames. This is pretty good because the concrete slab is non-resonant and the drywall vibrates enough to damp room modes.

Two kinds of rooms cause the most trouble:

1. Rooms with hardwood floors suspended over a crawlspace. This makes a resonant chamber with the floor acting like a drum head. It's impossible to get bass right in a room like this without doing something to fix the resonance of the suspended floor and crawlspace.

2. Solid concrete walls like in a basement room form well defined room modes, and that makes damper panels and/or multiple subs a requirement for good bass sound. I have also seen plenty of homes with plaster walls that are rigid. This is like concrete and doesn't provide much damping.

If you have rigid walls, these may help:

• "False wall" bass trap panels for concrete walls