It isn't even the quality of the subwoofer. It's just an amp design choice. If the amp has no current limiter, allowing it to play hard and fast, it can inrush. Some designs include a start-up current limiter, because that's when the capacitors will usually pull the most, and then disable it once it's up and running. Other amp designs always have a limiter in place (it is usually receivers that do this).
Normally even an amp without a current limiter will not pull more than what it's rated for from the wall (because of power supply design). They'll also have fuses set to blow if they try to. But as I was saying, some power conditioners behave badly when asked to deliver a large amount of power in a very short period of time. Rather than keeping the voltage at 115, they'll over-volt to try to make up for their lack of amperage. Hopefully it'll just blow a fuse on the amp, like Audioholics was seeing.
I only know of one power conditioner design which isn't current limited, and can actually provide more power than the wall via it's batteries. Those are the ones from
PurePower. I'm trying to find out if the ones from
Tripp Lite behave the same, as they are similar in their specs, but I can't find anyone to say one way or the other.
Looking at that APC, it's output will be stepped-sine (unfortunately pure sinusoidal regeneration isn't cheap). Stepped-sine isn't inherently bad, but can cause a different problem with high-draw devices. The hard "steps" of the sine wave produce harmonics in the AC, and can cause the windings of power transformer to "sing" or hum. You may even notice this on plasma displays, as they draw a lot and don't have room for big, well dampened transformers.
