the magnetic flux is really what you need to look at. sure you can have 500 ounce motor magnets out of ferrite (Eclipse titanium pro), but you can then use neodymium's (sp?) and have tiny magnets with 6 times the flux. We use the neo's on the very expensive PA 18" subwoofers. We are going to start using it sooner on the consumer stuff, but it is more expensive. The next generation JL audio W7 will use neo, but no one is supposed to know that. I'm guessing in a few years, most all of [our] higher end consumer stuff will be using neo. The only trick with neo is you need a larger steel bottom and top plate to control the flux so the motor ends up being still pretty heavy, but the actual magnets are much smaller.