# humming sub .....help lol



## Guest (Nov 11, 2007)

:dontknow:hello , i have a fosgate audionics 330 watt powered 15 in subwoofer its in perfect condition but even when it is off it hums ???? mabye dirty power ?????? helpppppppp


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## pwest (Oct 8, 2006)

Just a rookie guess. Might be a ground loop problem. Try different outlets or a cheater adapter.


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## Hakka (Sep 10, 2006)

try removing the antenna/cable box connection and see if that stops it.

Hakka.


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## eugovector (Sep 4, 2006)

I have the same problem with mine. I just power it down when I'm not using it. All the suggestions so far are good ones (cheater, unplug cable/antenna, move it to an outlet on the other side of the room)


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## thxgoon (Feb 23, 2007)

Does it hum when nothing is connected to it? ie just power. If so the problem is likely internal to the sub and there's not much you can do about it. If not then the problem is either a ground loop or faulty equipment up stream. Ground loops happen all of the time and can be a pain to diagnose. Most commonly it comes from a cable outlet. A ground lift can be purchased for about $30 that will address that problem. Otherwise you'll just have to plug and unplug until you find the problem. I noticed last night while calibrating my projector that whenever the screen is green I get hum from my subs. Looks like my projector is causing some sort of interference... so strange.


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## Guest (Nov 22, 2007)

jimmyzowens said:


> :dontknow:hello , i have a fosgate audionics 330 watt powered 15 in subwoofer its in perfect condition but even when it is off it hums ???? mabye dirty power ?????? helpppppppp


You may have a ground loop, caused by the total audio system not having a single ground point.
I would try, first, take an extension cord and connect your Subwoofer power cord to the same electrical outlet that your audio equipment is connected to. If the hum goes away, you are probably using two different circuits for your audio system. If that works, make sure to calculate the power required for the Sub (Amperes) as well as the power required for the rest of the equipment on that circuit to make sure that the potential draw is less than 15A for a 15A circuit or 20A for a 20A circuit. You would then need to have an electrician run power to you Sub location, from that circuit.
If that doesn't help, you may be getting a ground loop from an input into you system. Start removing inputs, such as Cable Tuner, etc until the hum goes away. If that works, you may need an isolation transformer.
Ideally, you system would have isolated grounded circuits which are all connected to a single ground.


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## Guest (Nov 22, 2007)

jimmyzowens said:


> :dontknow:hello , i have a fosgate audionics 330 watt powered 15 in subwoofer its in perfect condition but even when it is off it hums ???? mabye dirty power ?????? helpppppppp


You may have a ground loop, caused by the complete audio system not having a single ground point.
I would try, first, take an extension cord and connect your Subwoofer power cord to the same electrical outlet that your audio equipment is connected to. If the hum goes away, you are probably using two different circuits that have grounds that are not exactly the same voltage for your audio system. But make sure to calculate the power required for the Sub (Amperes) and the rest of the system to determine if the potential power draw in amperes is less than the circuits capacity. If that does work, you may need to have an electrician run a new power wire from the main circuit to the sub location.

If that doesnt work, try unplugging inputs to your system one at a time. Start with Cable Tuner box if you have one. The problem could be that the Ground potential (Voltage) of your system is different than one of the inputs, for example if it comes from another room. If it is from the Cable Tuner, you can use an isolation transformer if all else fails. Those work by allowing AC signals to pass and not allowing an DC current to pass. Since no DC current can pass, it elimates your ground loop.

Ideally, you determine the total potential power draw, in amperes, of your system to determine how many circuits you need. 20A circuits will help a lot. Then have your electrician install "Isolated Ground Circuits" which have a single physical ground connection to earth.

Good Luck
Rick


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## MatrixDweller (Jul 24, 2007)

Does it hum when there is no power going to the woofer (Put your finger on it gently and see if you can feel any faint vibration). If that's the case it could be a capacitor, although they usually emanate a high pitched whine.

If it's coming from the woofer then it probably is a ground loop or noise on the line. You could get a power conditioner or move it off that circuit. If you wanted to get adventurous you could have an electrician run one or two dedicated lines to your AV equipment (maybe even isolated grounds). That would probably cost you a couple hundred bucks depending on if there is room in your current electrical panel. That still might not fix it. If it's a ground loop from cable or antenna even isolated grounds won't help.

Ground loops tend to happen a lot on the cable TV line. Try unplugging things systematically one at a time starting with the cable TV box to see when the hum disappears. That will normally fix the problem. If it's your cable TV then try a ground isolator like -> this one <-. You can call your cable company and they might be also be able to help. 

What ever you do, don't connect everything to 2 prong adapters if you value your life. Many people do that but if there ever was a short to chassis and you or some one love touches it they could get a shock (possibly fatal).:dizzy:


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## basementjack (Sep 18, 2006)

Not to rob this thread, but Mine hums too - but it seems like a transformer hum - it comes from the back amp plate, not the subwoofer.

Any thoughts on that? 

I'll try the cheater, and also try it with no input connected to make sure it's not sneeking in on the RCA line.


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