Originally Posted by rbinck
In a vehicle one good sub is better. If you are going for more shaking add a tactile transducer under each seat like ButtKickers.
As long as the subs are good, I think more than one would be better, due to nodes and vehicle shape, and within reason of quantity and certainly size, but there is a tendency to overwhelm the rest of the frequency spectrum with pounding of base, and not really low bass at that, just for the sake of ego problems. And that is why a well designed, well balanced audio system is so rare in vehicles as to be extremely difficult to find. I heard only one truly well designed non-ego system in my life, and that was at the CES in Las Vegas, in a car set up by Velodyne several years ago, using multiple subwoofers (with accelerometers) specially designed for vehicles. No boominess, effortless, tight, natural sounding bass that blended very well with the rest of the speakers to create a sound much like a very good home system.
The butt kickers are not really musical, more of a gimmick, but when used very judiciously, can add some excitement to movie soundtracks. I attended a demo of the company's products that were hooked up to a couch on a plywood platform at CES, so I would nix them for music.
dave in Snohomish, WA