jakdedert wrote:
Ron(UK) wrote:
snipped for brevity

If you think about it, the bass drum head itself doesn't move much
when it`s hit by the beater, why should the speaker.

Actually, it does move quite a bit; but the operative dimension is not
the excursion, but the size of the head vs. the size of the speaker. To
move as much air as a 20-someodd inch bass drum head--moving x
distance--the 6 to 18 inch woofer cone has to move correspondingly
farther. I'm sure there's a mathematical relationship there that I
don't have the chops to calculate....

The majority of the initial energy is outside the range of the
subwoofer, also a bass drum (any drum in fact) is a tuned instrument.
the 'x distance' excursion as you put it, is very small in relation to
the sound output, maybe half an inch or so on a properly tuned bass
drum. Don't go by the front head which is often far slacker than the
batter head, sometimes it`s only there for show.

IMO
Ron(UK)