Subwoofer "popping" problem (1 Viewer)

[PaulW]

Late last year I moved into a new house and have a dedicated home theater room (yah!). In my old house I had no trouble with my Onkyo THX HTS-1 but in my new house I experience a “pop” in my subwoofers often when a light switch or ceiling fan switch is flipped in the theater room itself or the bath room next to it. This pop can be minor or some times very loud. I have the subwoofer plugged into a power strip which then is plugged into another higher quality power string. A pop happens about 75% of the time. Any idea what the problem could be?

Thanks,
PaulW

 

[Dennis Gardner]

To find the grounding problem within your house that is causing this may require an electrician to check all items that are on the circuit. Something has lost a ground, and the static is seeking the ground through your sub.

It sounds like static electricity working its way through your sub. If your sub has an auto-on circuit, it should stay off until a good signal reaches its input. If you don't have this feature, you can always switch the entire unit off until needed.

You might try hooking your power bars into the wall with ground lifting adapters (you remember those 3to2 plugs we had to use in old homes?) This would lift the ground from your system and may solve your problem. Most components don't have a ground anyway, but any item that does can get the pop into your sound path through its ground connection.

 

[PaulW]

My sub does not have a ground plug. I have a outlet tester to see if any of the outlets are mis-wired. I guess I would try a ground lifter but are those kinda bad to use?

Paul

 

[Dennis Gardner]

Its probably not a outlet. It is probably a light socket or fan wiring that is losing ground.

Use the lifter to find the problem, not as a permanent fix.
I have to use one on my projector, since it is on a different circuit and the ground is made through my VCR Tv cable then out through the S-video to my PJ. My componenets don't have a ground , but my PJ did and thus the ground finds its way to it.

 

[PaulW]

So how would I use the ground lifter on switches?

 

[Dennis Gardner]

The ground lifter is for your gear and just isolates the ground from the component that is amplifying the pop.

This is a cheap method of testing if the ground is an issue. If it doesn't fix the popping, then it is coming into your system elsewhere. I mention grounds, since they have always been misunderstood and troublesome for years.

 

[PaulW]

I got yah. I'll get one and "lift" the power strip I have it plugged into.

 

[Dennis Gardner]

No ground on the sub wire? Then it may be coming in from a source on your sub cable. This could be caused by a TV cable, phone line, or ethernet line hooked into a power bar or any other component. Find a switch that causes it regularly and try unplugging stuff until it goes away. It really is a trial and error elimination task, but worth the effort to save your sub and sanity.

On another note, do you live in the desert? This sounds crazy, but water your ground rod coming out of your electrical box. In dry climates they can lose contact with damp earth.

 

[PaulW]

I do live in the desert! Gilbert, AZ! I'll try that too.

 

[rob-h]

This is no way caused by static. Although the problem may indeed be a ground, it could also be the subwoofer cable or position. When a switch is closed it creates radio frequency interference. Thats what you are hearing. If you hold any radio next to a light switch while you flip it, you will hear the same thing. Its cause by the switch contact bounce. This RFI is somehow being induced into the subwoofer. Try disconnecting the cable from the reciver to the sub and flip the switch. Leave the sub plugged in though. If the noise is gone, you narrow things down.

 

[PaulW]

I did as you suggested. I recreated the popping then disconnect the receiver from my subwoofer and the popping went away. I guess I'll trouble shoot more now by disconnecting various devices from my receiver to isolate the source.

Paul

 

[rob-h]

Did you disconnect it at the woofer or the receiver? If you did it at the woofer, try leaving that connected and remove the connection at the receiver. If the popping is there, the subwoofer cable is acting like an antenna. Te sub woofer is just amplifying the noise. You can try rerouting the cable to see if it makes a diffrence. The cable itself maybe bad. Try a diffrent cable.