Hi Ken,
All joking aside, the VP100 measured in Axiom's anechoic chamber at 40 Hz is -20 dB "down" from its upper bass and midrange output levels. Even allowing for bass reinforcement from adjacent surfaces like your entertainment center, that would add 6 dB or perhaps a little more to its output at 40 Hz, leaving it -14 dB down. You might see the cones of the woofers move at 40 Hz, but I doubt you'd hear anything. More likely you'd hear the 2nd harmonic at 80 Hz and the VP100 would have significant audible output there.
As to subwoofer levels, it's also dictated by not just personal taste on the part of the mixing of the source material, but a matter of what is considered "realistic". If you were a devotee of disco-era music, the bass is usually mixed at a very loud level. I used to like some disco, on disc and in clubs, where the bass was incredibly loud. The latter was fundamental to the driving dance rhythms. In that sense, hugely powerful bass from disco music would be realistic.
In good concert halls, the reverberations of a big bass drum are certainly present, but they aren't overwhelming -- at Carnegie Hall and the Metropolitan Opera House, it's thrilling to hear them but they are not ultra-loud. When I play back well-recorded classical and opera works with bass drum, I tend to increase the subwoofer level, knowing full well that I'm playing it somewhat larger than life. I enjoy the surprise of a big drum hit in my living room. Am I a bass-head? Sometimes.
Regards,
Alan
