I recently purchased a pair of Bass shakers from PE. One was defective so I installed one under the seat of my couch. I've got an eq on it to knock out the 40-50hz peak and extend the 20-30hz range. I'm powering it with an H/K amplifier. The little thing is annoying. Its a small vibration that seems totally detached from the movie and especially music. It seems slow to react and feels more like a pager vibrating under me. It just doesn't seem realistic to me. Should I spend more money to get 4 or 8 more of these to improve the tactile sensation or should I spend my money elsewhere? I have a 7ft couch that I have braced moderately with mdf.