Not sure if I'm making an issue out of a non-issue, but I think my Buttkicker installation is sub-par based on the performance I am getting.
The single Buttkicker is located on 2x4s which are screwed to the middle of a 3 seat couch where the outer two seats are full recliners. The Buttkicker is wired with 12AWG cable from the Buttkicker amp. I have installed 7 of the 120lb kinetic isolators, replacing each of the seven feet of the couch. I estimate the couch weight at 230lbs, and factored 3 people at 200lbs for the math.
The Buttkicker is felt the most in the central seat, and delivers a small buzz during movies. This is with the crossover defeated and the volume set for 1/3.
The room also has a Velodyne FSR1800 and two Def Tech BP2000 front speakers for sub bass.
So I am considering two improvements - one is to replace the existing isolators with new ones. The current ones only have a deflection capability of 0.25". The new ones have a deflection of 0.50". Should I stay with 120lb, or beef it up to the 220lb that they are offering? I am concerned this will make the couch too 'stiff' if I go 220.
The second would be to remove the Buttkicker from the couch and mount it to some 2x6 rails which would run the entire length of the couch. The current location has the buttkicker mounted to the center wood frame, and I'm thinking the couch design is damping the effect to the outer seats.

Or I'm making an issue out of a non-issue.
Thoughts?
And thanks for any input - this forum has been excellent in helping me with my setup.

If all you are feeling is a small buzz there is defiantly something wrong. My Buttkicker feels like it will shake me off my couch. If you haven’t already check that the tranducer is working properly, put your hand on it while turning up the power. If it’s getting a strong signal it will shake quite violently. If you start hearing a sort of popping sound it’s turned up to high.

If the transducer is working right check to see how secure the 2x4s are. If they are flexing it will dissipate the vibration. In this case I would try bracing the 2x4s or better yet follow your idea of mounting it to 2x6 rails running the length of the couch. This should help distribute the feeling more evenly to the outer seats. That is similar to how I have mine mounted.

Also I found I don’t even need to use the isolators.

Try the couch mounting kit (http://thebuttkicker.com/home_theater/accessories/cmak.htm). It really only takes a few minutes to assemble and put in place, and it works very well across the whole couch.