I am interested in discussing amplifiers that are used to power subwoofers. I have four DIY subs powered by a Crown XTi-2002, wired for 2-ohm operation. I had recently read the Crown I have is less than ideal for sub duty, due to an overly aggressive high-pass filter. After two calls to Crown tech support, I came away convinced Crown does not have much interest in the subwoofer amp segment.
Prior to the Crown, I was running a Behringer iNuke 6000 at 8 ohms. The iNuke's marketing specifically pitches it as an amplifier that is good at reproducing bass frequencies. Both amps do their job reliably, and without stumbling. The question is this: can I do better strictly through amplifier upgrades? If the answer is yes, then what parameters matter most? I have read that one "ideal" amplifier for sub duty is the Lab Gruppen FP10000Q professional amplifier—is there better out there?
I am curious what qualities allow an amplifier to approach the "ideal" for subwoofer duty. Should it play flat to 1Hz? Should each amp be able to handle a 1-ohm load—or a 2-ohm load when bridged? Should the amp's cooling be entirely passive, or is it OK to use a very quiet computer fan? Does damping factor matter? Is it better to have four channels, how about four channels with the option to bridge into two?
Would modularity and expandability be appealing? How about a chassis with a transformer and slots for amplifier modules—three subs? Get three amp modules. Do you have six subs? Get six modules. If you have one great big subwoofer, get two modules and bridge them. Is your sub a dual-opposed 18"? Then try four modules total, bridged into pairs, with one pair powering each driver!
I am curious about output voltages and ultra-low frequencies. Do class D amps have issues with continuous output of infrasonic waves? Is there any advantage to class A amplification for low frequencies since it is the perennial favorite for full-range speakers? How about a dedicated 220 volt line—is that the ticket to real performance?
Finally, how about DSP? Would a stand-alone subwoofer amp capable of performing some kind of room EQ be appealing? What if delay, EQ, phase, high-pass and low-pass filters were all programmable through an app?
Now I know I could leave my amps alone and look at building new subs and/or shopping for upgraded drivers, but I really am more interested in discussing amplification. I've asked a lot of questions, am interested in serious answers. I appreciate any insights into the topic. Thanks in advance for keeping the discussion civil.
Big subs need big amps - photo ©2013 by Mark Henninger