I have an issue with an Energy ESW-8 subwoofer that I bought a while ago as part of an Energy 5.1 speaker set. At that time I tried hooking it up to my home theater system, but it had this low rumble that just grew louder and louder, even with the receiver turned off (though the rumble doesn't get as loud as quickly as when output is played though it). I chalked it up to getting better speakers than my cheap HT receiver at the time, and just went back to the old sub I was using.
Well, fast forward to today, I recently got a new HT receiver (Yamaha RX-V4745) and thought I'd hook up the Energy sub again. Nope - same problem.
So the best I can figure is that either I'm doing something very wrong, or the the sub is bad and I'm out of luck.
The only way I can really describe the sound is a low rumble... kind of like the sound effect movies and video games often have for underground lava pits, but when playing output it grows quickly from a background rumble to shaking the the whole house, even without the volume of the source or anything changing.
Its hooked up to my receiver via an RCA cable that was designed for subwoofer connections (with the tighter fit, etc). It goes from the sub pre-out on the receiver to the left input on the sub (the sub has "left" and "right" inputs, and the manual says to use the left one).
I've tried both leaving the other knobs and switches alone, as well as fiddling with them to see if there's anything that fixes it, but to no avail. (FYI, one of the switches on the back is a phase switch with 0 and 180 as the settings, I leave it at 0. There are two knobs - a volume knob and a filter knob. The problem persists even with the volume knob at minimum, and even with the receiver putting out minimum volume - the noise will grow until it literally shakes the whole house).
Any ideas or suggestions?