Hello peterb,
There is nothing new about servo-feedback design in subwoofers and Axiom isn't interested in servo-feedback designs. These have been around for decades and used by such subwoofer brands as Velodyne, PSB and Paradigm in numerous models that deliver very good performance, better than would have been achieved without servo-feedback integration.
However, Axiom believes that our DSP design in the EP500 and EP600 subs is superior to the older servo designs in a number of important ways. Without going into a long dissertation, using a custom-written DSP algorithm that contains all of the traits of our particular dual-voice-coil driver, the enclosure, our amplifier and the expected performance goals results in an integrated system that delivers much more linear performance and optimal output well into the sub-sonic region.
Moreover, using a custom DSP algorithm means that the sub can never be overdriven or damaged. The algorithm was arrived at throught constant measurements and test of the driver, the amplifier and the enclosure, with any non-linearities (deviations from the desired frequency response) compensated with new instructions in the digital code.
