The Clark Synthesis Platinum Tactile Transducer is the most powerful tactile transducer created by Clark - or anyone. But this baby ain't cheap: all that extra power is going to cost ya'.
The Clark Synthesis Platinum
Price: $550 from Amazon
At around $550, the Clark Platinum is a top of the range product. But what it gives you in return is a hell of a lot of shaking power. It can move 6.9 pounds per watt. That's a lot of shake. At its peak, the Platinum will shake at 932 lb-ft. Compare that with the ButtKicker, which has a tactile peak of 216 lb-fit. When there's an explosion on screen, you FEEL it in a profound way. For home theater projects like raised seating platforms, this is the icing on the cake.
With that much power, you're really going to have to get some good quality isolators to stick under your couch. Clark makes their own: they're expensive but worth it. See the isolators at the Clark Amazon store.
Unlike bass shakers which only vibrate at low sounds, the Clark Tactile Transducers respond to the full range of sounds - all the way up to 17kHz. So if there's a cymbal crash or violins playing, you'll feel the vibrations. However, be warned that sometimes the Platinum will shake to things you don't want to feel: like voices. You can use a low pass filter to cut out the higher vibrations, or just play with the settings until all you have are those good, low sounds. (Find out more about low pass filters and cross overs.)
The Platinum may be more expensive, but if you're using it in your couch, you'll probably only need one transducer (strategically placed), rather than two, three or four cheaper shakers.
It may be overkill, but what a great way to die.