PS3: Gaming headphones not "balanced" on left and right speakers

I'm currently using the Turtle Beach PX21's, which has an "expander" feature, that basically makes the sounds more to the left or more to the right.

When I first got them (yesterday), they worked fine, with or without the expander feature turned on. However, when I plugged them into my computer (with expander turned on) then plugged them back into the PS3, I noticed that there is less sound coming out of the left speaker. This is with expander on. Fortunately, if the feature is turned off, the sound is balanced.

The weird thing is, it is completely fine on the PC. So I'm guessing that either the headphones or the computer made changes so that the PC sounds come out balanced, but then didn't change back when I plug them back into the PS3.

Anyone got a fix for this? If not, I can just go backa nd excahnge for a new pair (I believe I have around 30 days to return them.) Thanks!