If they're in separate chambers then you're fine and don't need to take the second sub out. And I don't take offense, I probably should have elaborated in my last post. Basically with only one sub hooked up in a chamber meant for two subs, that one sub is seeing twice the volume of the box that it should. Even though you may have a (example) 2 cube box with 2 subs, when both subs are playing, each sub only "sees" 1 cube itself. However, if only one sub is playing, it "sees" all 2 cubes. Mechanical power handling decreases as box size increases because the air spring behind the sub is not as tight. As a sub plays and the cone moves, it compresses the air within the box. The more air that's in the box, the more the cone of the sub has to move to compress the air to the same pressure. Does that make sense? The compressed air within the box is acting against the cone of the sub as it moves inwards, towards the inside of the box, therefore helping to limit the excursion of the sub. Likewise, when the cone moves outwards, there is actually less pressure within the box than there is in the outside world, so that helps to suck the cone back in. However, if there is more air within the box, the sub can move farther because the pressure within the box is not building as high on the instroke and does not put as much counteracting force on the back side of the cone. To view an easy example of this take a sub out of a box and play it free air and note how high you can turn the volume knob before the sub has reached full excursion (warning, be careful as this will be with very little power). Then place the sub into the box and notice how much higher you can turn the volume knob (power) before the sub reaches full excursion. The free aired sub is the extreme of having no back pressure on the cone at all, so it moves very easily and is only dependent on the surround and spider of the sub to keep the cone from just flying off.