I checked my 3c/f sealed Shiva today with some movies. Overall I thought it gave very clean bass, but the bass wasn't really "bone crashing". I never thought it will be "bone crashing" since it is in a closed box (even though I once heard a Servo-15 sub, which is also closed, and the bass was "bone crashing", but it is a 15" driver) I was ready to draw my conclusions about this sub, but thought I would try to drive it harder before I come to any conclusion. I played the Dolby Digital trailers, and turned the volume control to 1/3 way up (the amp is rated at 272w @ 4ohm). When I played the "Dolby Digital Rain" demo, I couldn't believe my ears, there was a strong bass effect which lasted 2 seconds and it almost tore my room apart. I took my RS SPL meter, played it again, and measured close to 110db SPL at the listening spot, uncorrected!!!. I think that this bass effect (the splash of the water) is centered at about 20-25hz (can anyone verify?), which mean I should add about 5-7db SPL to my readings. I never read that the Shiva in a small closed box can give ~115db at 20hz. My question is : am I ruining the Shiva ?, I mean, when this bass effect was playing, I noticed that the driver was going back and forth like crazy. The bass was clean, but when I turned all the speakers off except for the sub and played it again, I heard some noise from the driver when it was playing this bass effect (If I was bottoming it, why haven't I heard noises when the other speakers were on ? usually when people report that they bottomed their sub they say that the bottoming noise was masking the sound of all the other speakers). The pressures on the Shiva seemed huge, can the Shiva withstand such pressures without damage ?. You have to remember that I was using only 33% of the amp's power (unless the volume control is not linear), which mean ~ 90watts. If I'm not ruining anything and these are the true capabilities of the Shiva, then I have underestimated it by far. when I think of it again, my question is even simpler that I thought: Can the Shiva driver in a sealed 3c/f box withstand 100 watts of power all centered at ~ 20hz ? (If the limit of power in this situation is lower or higher than 100w, what is it ?) P.S My room measures are 13x9x8 feet and the room was closed during listening.