speaker hum

**mightypants** · **11-06-09, 02:14 PM**

I'm getting a high pitched hum from my speakers whenever my stereo is turned on. I have a Sony STRDG720 and a set of Cambridge Soundworks satellite speakers (2.1). I've had the speakers for about 12 years, and the stereo for a little less than a year. I had no problems with this setup from January to May of this year, but when I set it up again after moving to a new place in May, this hum appeared. It isn't so terrible that I can use the system anyway, but it's very noticeable when the other sounds coming through are quiet.

I was wondering if anyone has any recommendations on how best to troubleshoot this problem. I don't currently have another pair of speakers or a receiver to test against. Thanks.

**tonyvdb** · **11-06-09, 02:16 PM**

Its sounds like some interference in the power, Is this an apartment that your in?

**mightypants** · **11-06-09, 02:28 PM**

No, it's a house.

**Anthony** · **11-06-09, 02:31 PM**

When you say high-pitched, what frequencies are you talking about? If you need to compare, there is a frequency generator in Room EQ Wizard, available for free on this site. You can listen to some tones and tell exactly what frequency the hum is at. That may help diagnose the problem.

When I hear hum, the first thing I check is the cable connection. This is usually for the lower 60 Hz hum from the power line ground loop. Best way to check is to disconnect the cable from the wall to the set top box, power strip, VCR, TV, etc. If the hum disappears, that's your culprit.

If the hum remains, try looking for any piece of gear that has a third prong, like an amplifier (although it could be anything). Unplug that and see if the hum remains (as long as it isn't the one thing powering the speakers

)

Higher pitched hums can be radio interference on some of the signal wires, try moving them around to see if it goes away. A bad capacitor in a crossover can cause this as well, but that is much less common.

Let us know what you find and we can help with a solution.

good luck.

**mightypants** · **11-06-09, 02:47 PM**

Thanks for both those responses, I'll check the frequency of the hum later and report back, though I'm pretty sure it isn't at 60 Hz.

**tonyvdb** · **11-06-09, 02:55 PM**

have you tried to move the receivers power to another plugin in another room using an extension cord to see if the noise goes away?

**eugovector** · **11-06-09, 04:00 PM**

What devices are connected to the stereo. I have a ground loop in my cable connection at one apartment. Try disconnecting the co-ax cable, if you have one, and see if it goes away.

**selden** · **11-15-09, 03:19 PM**

Is it coming from one particular input device or all of them?
Do you have a cable TV connection? They're a common source of noise.

If you aren't already using one, get a high-quality surge-suppressor power strip which includes power-line filtering and CATV cable protection, too.

Is there a radio transmitting tower nearby? They can cause nasty interference problems. Shielding hifi electronics against that can be quite expensive.

**steiny93** · **11-18-09, 10:33 AM**

faced a similar issue (although it was low freq hum) turned out to be coming from the catv line

interesting is that in my scenario there was a surge-suppressor inline which included the catv protection but it didn't work

i diagnoised it by removing all connections then adding them 1 at a time until we discovered the issue

**eugovector** · **11-18-09, 11:44 AM**

Had the same problem. Surge protector wouldn't help because it wasn't a problem with the electricity, it's an improperly grounded cable connection to your house that causes a ground loop.

Drove me nuts, and I solved it by getting rid of cable TV

**mightypants** · **11-18-09, 04:08 PM**

Hi all. Thanks again for the responses. I checked the frequency of the noise and it sits around 1.6 Khz. This is a pretty old house, and most of the outlets are only two-pronged. There are a lot of cables running near the speaker cables, so I suspect it is indeed an interference problem. I'm inclined to just deal with it for now, since I won't live here for too much longer. However, if anyone has any fairly simple ways to reduce/eliminate the problem, I'd be happy to hear them. Thanks.

**steiny93** · **11-18-09, 04:16 PM**

try unhooking stuff until it goes away, then when you find the source try moving the wires that are connected to that source

i believe the rule of thumb is 1ft separation for parallel runs and the rest of the crosses be at 90 degrees.

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