dual sub set up, one hums but not the other?

[blue11]

I currently have a dual sub set up and am experiencing what seems like an intermittent ground loop issue on one of the subwoofers. It "hums" on and off intermittently, mostly when I change channels. it would hum for a second or two and then go away. When a signal goes to the sub it hums for a bit then goes away similar to the length of time when changing channels, but sometimes it persists for a few more seconds
I don't believe it would be caused by the STB feed since only one of them hums. Would that be correct?

I've tried switching outlets on the power bar I have my components plugged into but the problem is still there. I haven't done a lot of cable management but have tried my best to separate the cub cable from any other cables. I've also tried using the other sub cabe to see if it was a shielding issue but the problem persists.
I've read a few other threads and the gound loop issue thread but I would have to say, I am lost at that one.
Any other thoughts?
Here's a list of my components:

42" LG Plasma
Yamaha RX-V663
Paradigm Cinema 110 CT
Paradigm DSP-3100
PS3 (80 gig)
Motorolla DSR 505 (STB)
Kensington i-pod dock

all but the TV is plugged into a power bar, not an expensive one.

any help would be greatly appreciated.
thanks in advance guys

[Big Daddy]

1. Read Ground Hum & Ground Loop Isolators.
2. Make sure the sub cables are shielded RG6 type cables.
3. Timers, dimmer switches, washing machines, microwave, etc. can create hum.
4. Sometime, the new power saving light bulbs can create hum.
5. Buy a ground loop isolator.

If you check and try everything and nothing helps, it may be the subwoofer amplifier.

[callas01]

Originally Posted by blue11

I currently have a dual sub set up and am experiencing what seems like an intermittent ground loop issue on one of the subwoofers. It "hums" on and off intermittently, mostly when I change channels. it would hum for a second or two and then go away. When a signal goes to the sub it hums for a bit then goes away similar to the length of time when changing channels, but sometimes it persists for a few more seconds
I don't believe it would be caused by the STB feed since only one of them hums. Would that be correct?

I've tried switching outlets on the power bar I have my components plugged into but the problem is still there. I haven't done a lot of cable management but have tried my best to separate the cub cable from any other cables. I've also tried using the other sub cabe to see if it was a shielding issue but the problem persists.
I've read a few other threads and the gound loop issue thread but I would have to say, I am lost at that one.
Any other thoughts?
Here's a list of my components:

42" LG Plasma
Yamaha RX-V663
Paradigm Cinema 110 CT
Paradigm DSP-3100
PS3 (80 gig)
Motorolla DSR 505 (STB)
Kensington i-pod dock

all but the TV is plugged into a power bar, not an expensive one.

any help would be greatly appreciated.
thanks in advance guys

you can try a cheater plug or adjust the phase on the back of the sub, adjust the phase and see if helps.

[blue11]

what's a cheater plug?

I tried adjusting the phase to no avail. I'm going to try and clean up the wiring this week to see if that helps.

[Big Daddy]

Originally Posted by blue11

what's a cheater plug?

I tried adjusting the phase to no avail. I'm going to try and clean up the wiring this week to see if that helps.

They are available at Wal-Mart for less than $2.

[blue11]

thanks. I'll try and get one tomorrow.

[blue11]

I couldn't find one of those cheater plugs at the Walmart or Home Depot around me.
I cleaned up the wires a bit but the hum is still there. I disconnected the cable tv but the hum did not disappear. I played a dvd that had some bass and checked both subs to see if they both hummed. Only the DSP hummed.
I'm going to switch the sub cables again and see if that solves it. if this doesn't work then I'll try and get a ground loop isolator.

any other thoughts?

EDIT: switched cables, same result.

[HAMP]

Originally Posted by blue11

I couldn't find one of those cheater plugs at the Walmart or Home Depot around me.
I cleaned up the wires a bit but the hum is still there. I disconnected the cable tv but the hum did not disappear. I played a dvd that had some bass and checked both subs to see if they both hummed. Only the DSP hummed.
I'm going to switch the sub cables again and see if that solves it. if this doesn't work then I'll try and get a ground loop isolator.

any other thoughts?

EDIT: switched cables, same result.

I'm sorry for this silly question, but does it humm if nothing is connected to it? or what about another device like the left or right output from your TV itself.

[blue11]

not a silly question at all Hamp.

nope, it doesn't hum if nothing is connected at all. the hum only occurs when I change channels and when a signal is going to the sub. the weird thing is too, when there is a signal, it will hum for a bit while the sub is working and then go away while the sub continues to work it's way trhough the signal. Once the signal stops, it will hum for a bit and then go quiet until a signal is sent again.
I hope this isn't a sign of a more serious issue.

[gotmule]

From your last post, it sounds like it is something internal and not a ground loop. It could be a loose connection or a solder that acts up when a signal is passing through it. Is it still under warranty?