Now for the long version.
I got interested in the idea about 5 years ago. At the time all of the options were very expensive and were outside my financial reach. I did some research and decided to build my own unit out of an old RCA 150W powered subwoofer.
To my surprise this design worked amazingly. When connected to the original subwoofer amp and mounted in the entertainment seating, it produced tons of low frequency tactile feedback and no audible sound.
A lot of DIY tactile transducers seem to focus on attaching weights to the voice coil after removing the speaker cone. This seemed counter intuitive since the driver itself was already of considerable mass. I decided to build a setup where the voice coil was used to move the mass of the magnet. I first removed the speaker cone and dust cap. Then I cut down the basket to about 2/3 of its original diameter and removed two of the baskets 6 arms.
I found a polymer caster wheel to be the perfect fit where the dust cap had previously been. A bolt was connected to the wheel and the wheel epoxied onto the remnants of the speaker cone with the threaded end of the bolt pointing away from the voice coil.
I cut a circular plate of 1/8" aluminum to match the new diameter of the basket arms and trimmed off the excess to give a somewhat oval pattern. This excursion restrictor plate served to provide resistance against the voice coil so that it wasn't "overdriven?". The aluminum plate also acted as a bit of a mechanical frequency filter. A string vibration restrictor plate also means that heavy vibrations die out quickly an do not leave any lingering sensation like some other models can.
A hole was drilled in the plate to allow the threaded bolt to pass through. The restrictor plate was fastened to the basket arms with machine screws (with thread locker) and L angle brackets that were re bent from 90 degrees to 45 degrees. Polymer pacers were used to offset the restrictor plate from the surface to which it would be mounted and the whole assembly was tightened together. When assembled there was no play between the bolt, the restrictor plate, the basket and the voice coil. All of the parts made contact, and the only room for movement was in the voice coil itself and the flexing of the restrictor plate.
This setup worked perfectly untill one of the recliner mechanisms clipped the power cord like a pair of scissors. In that split second my LFE amp, my receiver, and my TV all were fried. After replacing both my main TV and receiver, I abandoned the tactile transducer for a while (mainly because that is what my wife blamed for the destruction of our previous home theater).
When I saw samsclub had the buttkicker advance wireless kit in holiday season 2009 I knew this was my way to get some good vibrations back into my HT setup. It used a wireless audio transmission to the buttkicker amp and a new buttkicker brand transducer suitable for 1 couch. New non reclining furniture made this even safer. I got the kit for Christmas that year and I tried to love it. I first used the under the couch foot mounting method, but that didn't transfer enough vibration and it was very uneven in distribution to the seats. Then I mounted the transducer in the middle of the couch coupled directly to the frame. Still the vibrations were either too weak or it bottomed out (loud clank) during strong punches of low frequency bass. I kept this setup for a while but it had to be turned down to the point that it had almost no impact during normal action sequences. I couldn't help but think of how my build would work much better since the design was incapable of bottoming out.
After a while I was very disappointed that the buttkicker product couldn't live up to a first run home built hack job that I built for $50. I needed to see if my transducer would work with the buttkicker wireless amp.
Well almost a year and a half later I finally took the plunge. I re-mounted my subwoofer voice coil based tactile transducer in the couch, and all I can say is WOW! I was worried that the buttkicker wireless amp wasn't as powerful as it claimed, but it turns out the buttkicker transducer just doesn't know how to use that power. This really completes my 7.1 setup and makes movies and games very emersive.
Sorry for the long post but maybe someone else can learn something from my process.