GregS wrote:
Another thing, if the floor is vibrating from the air vibrations, and
the speaker is still, the floor will make the speaker shake.

Yes.
But if the floor is vibrating from the air vibrations, you have a more
serious problem than that. A common one, but serious nevertheless.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."