Silent Subwoofers ie: Buttkicker -your thoughts?

I am a huge movie fan, and have finally completed my theatre room. I have one final question, does anyone out there have any experience with the 'silent subwoofers' such as the Buttkicker made by Berkline. They are generally used to mount to a chair or couch and shake without making any noise. Their purpose is to make your couch feel like it is rumbling when a volcano erupts or when a building blows up.

Are these things for real or are they cheap gimicks that are useless???
I sat in one at CES, where I got to feel the chair shake when depth charges went off in "U-571." This really does not do much for the theater experience (worth a few chuckles more than anything else).

It kind of reminded me of "The Tingler." When that Vincent Price horror flic came out in the '50's, some theaters installed special devices in the chairs. Actually, what they did was wire up rivets in the hard bottoms of the chairs, so people wearing shorts (it was a summer release) would get a pretty nasty jolt of electricity at the appropriate moment in the movie. I wonder why this feature never caught on.
I have used similar devices - tactile transducers, but in the end preferred a good subwoofer instead for HT. The reason is the time coherence; the rumble hits you instantaneously. And unless your HT processor is capable of adjusting the LFE signal to zero (in distance) relative to all the other channels, it is (pardon the pun) a jarring experience. And even if it is set correctly, the effect isn't what I was expecting, especially if you are also using a subwoofer in the mix. Without a sub, it probably could be useful. It was nostalgic and even fun. But, the overall effect is quite an unnatural feeling. In other words, it just doesn't sound and/or feel right. OTOH, a good subwoofer more than makes up for a good rumble. And sounds much more natural than a tactile transducer (IMHO).

I have since kept my transducers, though, for headphone listening. The time coherence is not a factor, since both tactile and audible reach you at the same time. It is an excellent device for drummers in the pro-audio recording environment, which is where my application is now.
If you have throom and ability, IB subwoofers give you all the bass you can want, and will shake the floor if installed in the floor, like I have.
google "infinitely baffled" and read away.
Great suggestion!
Of course, my floor is concrete! Anyone ever do in-ceiling subs as opposed to in-wall?
Buttkickers and the like just seem too gimmicky. I have two 18" infinite-baffle
subwoofers mounted in my ceiling (you need to have attic space above for these to work properly). I, too, have a concrete floor in my listening room. Those two subs move such incredible amounts of air that I swear they shake the concrete.
When I watch "U-571" (and well below THX levels, which I find absurdly loud), it feels and sounds like you're in the submarine when the depth charges go off. Reproducing good low frequency is all about moving lots of air and when you move lots of air with quickness and impact, the results are quite impressive, if not startling.
It felt to me like the imax theatre at jordan's in massachusetts was using somethign like this. the seats would shake a lot, often when there was no associated bass sound, and the time was slightly off. i was with a bunch of people, none of whom are audiophiles. none of them noticed, but i didn't like it. -dave
Its very easy to use too much with the tactile devices. Used correctly , it can be effective on theatre . Its a balance between xover and output and positioning under the listening chair . You must also be careful how you isolate the rest of the surfaces touching the floor. That said , its fun when implemented correctly.
Cheap Gimicks.

If you want to go to the next level for home theater you need D-BOX motion seat platforms. After selling and designing high end home theaters for 10 years it was my first ah-ha moment.
Steuspeed . Yes, you are correct , the D Box is a one of a kind product that delivers. I see prices have come down considerably from their astronomical levels so maybe its time to revisit them . Good tip.
How much does a D-Box chair run at these days? From what I saw on thier site, it only works for specific movies?
I use these and with good setup and with volume moderation it is a nice effect. Many tend to set it too high and I could see where it surely would stand out and be very gimmicky. But I've experienced a few setups that were done well and in many cases you wouldn't even know they were there per se. I have mine mounted on a platform beneath the couch and with the platform decoupled from the floor and the effect is seamless for my enjoyment. I did try it mounted directly to the couch and yes there was a time alignment issue in that case. But most people I know use the platform or floor joist mounting approach. To compare an IB subwoofer system to buttkickers isn't fair, to different paradigms etc...

I really depends on your tastes, expectations, setup etc...
One good thing and the reason I bought them is for late night movie watching and wanting some impact without having the sub infrasonics throughout the rest of the house. It works perfectly for me in that regard. I think it's a viable options to consider and try, it's inexpensive enough. The D-Box is something different and much much more costly etc..., really not fair to compare the two IMO either. Again, that's like someone asking about a $500 CD player and getting recommendations for $5000+ reference players.
I know people who wouldn't consider their home theater experience as enjoying without their tactile systems in place.
I am not sure where pricing is these days as I have been out of the business for a while. They now offer the chairs with the built-in motion legs. These were supposed to be a more affordable option.

As far as available movies they are constantly adding to the library, and they won't miss doing any action movie you want. Effects are beyond just rumbles and explosions. While watching the Matrix when Neo steps out on the scaffolding. you start to sway around. This was VERY convincing while watching 100" screen. I was like get me off of this I want back in the office NOW! Whew... cool I gotta have one of these someday :) Yeah, it's a lot more $$$ than butt kickers, but many on these forums could easily afford it. Movies and video games will never be the same.

In the future D-box systems may be installed in theaters. Higher priced tickets would get you the premium motion seats.