psw125 hook up

mghamms

I have a lg lhb535 surround and a psw125 subwoofer. When i hook the LFE from the subwoofer to the subwoofer output on the lg it work fine. When i shut the lg off then the subwoofer makes a a humming sound and never shuts off.
I hooked up the lg sub out to the right speaker in on the polk and everything seems OK.\
Is this the best way to connect the two?

dorokusai

It sounds like a ground loop.

What happens if you shut the subwoofer off first, then the LG?

mghamms

I don't think it a ground loop.
Two prong plug on the polk sub.
I tried reversing the plug and moving, disconnecting the ground wire for the LFE.
I also tried a ground wire connecting the sub and lg to a good ground.

The sub still hums when turned back on.

dorokusai

What are you refering to in regards to the ground wire for the LFE? There's no need for a ground wire.

mghamms

LFE has 2 wires one is a shield, negative? ground? the other signal, positive?

RuSsMaN

That system uses a passive subwoofer, the only output is a single pos/neg speaker output just like every other channel. There is no dedicated LFE rca output. I would try to hook up both left and right outputs into the 125, and run the 125's outputs to the left and right mains.

The only issue is that you have no ability to select large or small, or crossover frequencies in the system. The LG system is designed to be used with the provided speakers, hence the lack of configuration options. It doesn't make sense why one speaker level output, subwoofer or main, would cause hum and another wouldn't.

What you are describing is a ground loop, as mentioned above. What other video sources are connected, cable, sat, etc. You can try disconnecting them one by one and seeing if one of them is causing the loop.

Try the left and right mains to the sub, then out to the speakers, and see if you get any real bass response out of the 125.

Cheers,
Russ