High-end audio speakers are very powerful in the deep bass range. We don’t want them to shake the exterior walls or roof of the building. Usually, neighbors don’t appreciate booming bass in the middle of the night. So where the room is located with respect to the neighbors is also usually important. It’s best if the main house is positioned between the listening room and the nearby homes so the main house blocks the bass waves from impacting neighbor homes.
If bass wave does impact a neighbor’s home, the wavefront should impact the corner of the house not the flat wall of a house. Imagine the prow of a ship breaking huge ocean waves and you’ve got the right idea.
Suspended wood floors under speakers is not desirable, they flex too much and act like a sounding board. Concrete floor works best. If we are stuck with a ring foundation and floor joists, we build large concrete pads into the ground on which the speakers are located and build the wood floor around the pads. If we can’t do that then we seriously support the floor joists with beams and pads to the ground under the speaker location.
A very lovely setup is to have… tune in next week for the answer!