The subs I have are still in the design stage, but they are NHT 1259 12 inch drivers in a 3 cf sealed box. They are reasonably efficient (90 dB SPL, I think), but the main reason I want a plate amp is to locate the amplifier in the subwoofer enclosure. Class D (or its progeny) mode looks advantageous to me because they run more efficient per watt of output power (since the power stages are essentially biased by the input signal instead of a constant voltage or current bias as with Class A or AB amps), and I can then plug them into the nearest outlet without worrying about rerwiring it to handle 20A for a less efficient amplifier. Also, any high frequency noise issues that might come from the switching power supply of Class D amps will not be as big a factor for a subwoofer operating at 100 Hz or less. Finally, they are significantly cheaper than most traditional Class AB amplifiers, which means I can take a chance on them without risking a lot of money if they don't work out. I will probably run stereo subs for the zone, which means I also need a means to adjust the phase for each sub, and it is very desirable to have an active crossover to fine tune the crossover frequency in real time.
