Try this: Turn the subwoofer volume on your receiver all the way up to its maximum setting. Then, adjust your subwoofer's manual volume control accordingly.
That should help quite a bit...no limbo stick required.
I have an HSU-STF2, and the only time I ever have that happen is when I'm listening at a REALLY low volume. Then again, I can always just flip the switch to "ON" from "AUTO" because I sit right over it at my computer.
I don't know if this is the answer you wanted, but something to fix your EP350 problem. Sorry, now you can't use that as *another* excuse to upgrade to the EP500.
