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Loud humming coming from subwoofer

I just moved and the system worked perfectly before it was disconnected now as soon as I plug the power cord into the sub it starts a loud humming. gets a little quieter as soon as I plug in the satillite speakers but is still there even though it is not even hooked up to the computer. I reinstalled the drivers in my computer for sound (headphones work fine) Sounds like they are getting to mush power???? Clueless..... Boston Acoustics Gateway Digital BA735 Speakers With Subwoofer

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  • zach20 Dec 04, 2007

    my mom did a recovery on my computer and now my speckers are huming

  • Anonymous Nov 22, 2008

    humkming noise but everything hooked up rite

  • Anonymous Jan 05, 2009

    But, with knowledge of electronics, I believe the problem is in the board in the bass speaker. To be more precise, it is most likely the big capacitor next to the diode brige rectifier(c59). I'll know for sure when I get a new capacitor. I do however wish I had a Schematic for this board.

    Thanks,
    John

  • Anonymous Jan 09, 2009

    speakers

  • itsawhoa Feb 08, 2009

    I have same problem. Hum is not from external source seems to be something amiss in the electronics inside the sub cabinet. How would I indentify the Capacitor that was mentioned in the other post.

  • kansasbarn Feb 16, 2009
  • kansasbarn Feb 23, 2009

    I have the same problem. I moved the subwoofer away from the cable clutter and that reduced the humming but it did not eliminate it completely.

  • kansasbarn Feb 23, 2009

    I have the same problem. I moved the subwoofer away from the cableclutter and that reduced the humming but it did not eliminate itcompletely.

  • raisingkane Mar 04, 2009

    I have the same humming coming from my sub and satellites. I have checked my power supply and video card, but by just powering up the sub/speakers and the humming starts. It just happened all of the sudden. An earlier thread mentioned replacing the C59 capacitor for the fix. Does this fix the problem? What is the value of the cap and where did you buy it from?

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This can be caused due to an increase in local interference. The hum is decreased when you plug in the satellites because the interference is spread over a longer area. You may notice that speakers tend to hum around things like cell phones and power outlets. To see if this is the case, move the speakers to another part of the room if you can, slide the desk around, plug the computer in at another room, something like this. If the hum gets louder or quieter, it is interference at your new place. This can be solved by finding a new area to set up your computer stuff at. Since it's mostly the subwoofer, try elevating it off the ground, there may be a power main running under the floor.

Posted on Sep 04, 2007

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The hum problem can be fixed in two ways.

First unscrew the 18 screws and fold out the heat-sink back-panel. Look inside towards the right and you see the ring-transformer.

Using a 14mm wrench-key you can either(1) tightened the loose bolt or(2) completely remove the transformer and with tie-wraps fix it to the rear side of the wooden triangle. Put some foam-plastic cushion around the transformer, isolating its vibrations from the box.

I now have one pretty silent(1) and one completely silent(2) bass units.

Posted on Sep 13, 2009

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Check for improper connection or no ground like a jack thats only half in or wires reversed.

Posted on Sep 04, 2007

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4 Answers

Klh powered subwoofer model ASW10-120B... when you plug in to power... it makes a loud buzzing/humming noise


I would check the caps on the power supply. They are rather large electrolytic capacitors that will look like they burst and/or leaking. When these die, the caps ground and the sub will make a loud buzzing sound. If you are handy with a soldering iron you can replace them yourself. Replace them with the same voltage or a little bigger and same with the size.

If the cap. says 16v 4700pF on it, for example, a 20v 5300pF or a 16v 6200mF cap. will work for this application.

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Jan 05, 2016 | Audio Players & Recorders

2 Answers

Why does my HTS-20 powered subwoofer make a low hum when plugged in, even turned off and not connected to the receiver and a louder hum when the subwoofer power is turned on?


I suspect the amplifier is damaged. This is not an easy repair to do unless you are well versed in audio electronics. I would recommend a repair shop to look at the subwoofer amplifier.

Jun 03, 2015 | Infinity HTS-20 System

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KLH HPS 1100 powered subwoofer. as soon as plugged into AC we get a loud hum from spkr. had unit for 8yrs.


Hum usually indicates a power supply problem. If it has an internal supply you will need someone to check it's producing clean DC. Alternatively if you do open it (beware risk of shock!!) initially visually check condition of /replace any bulging electrolytic capacitors.

Jun 27, 2014 | Audio Players & Recorders

1 Answer

Loud hum from subwoofer


The number-one cause of subwoofer/speaker hum is the coaxial cable connecting your cable or satellite receiver to your provider (either through an inground run to a cable box or through a satellite dish). Here is how you test for this:
  1. Turn your system on and get it to produce the hum by watching a movie. Pause your DVD or videotape so that the hum is all you hear.
    TIPDon't use a normal cable or satellite program for this; you're about to disconnect the cable that provides the audio and video for your cable/satellite feed.
  2. Find the coaxial cable running from your cable or satellite receiver to your service provider, and while listening to the hum, unscrew the connector and disconnect the cable.
Did the hum stop or reduce by a large amount? If so, the cable you disconnected is the source of the noise. If this is the problem, you have several ways to fix the issue permanently (if not, jump ahead to the next section):
  1. Call your cable or satellite company and ask for a service call. Sometimes you get a smart cable guy, and if you demonstrate the problem he can do something upstream to ground the coaxial cable and remove or reduce the hum.
  2. Buy a power strip that has F connectors as part of its surge protection. Plug the strip into the AC outlet and feed your main coaxial signal through these connectors. This ties the shielding of the coax (the source of the noise) to your AC ground and sometimes can solve the problem.
    WARNINGOddly enough, this solution (surge protection) can sometimes increase the humming.
  3. Go to your local RadioShack store and buy three inexpensive items: a Matching Transformer (part #15-1253), an Indoor/Outdoor Matching Transformer (#15-1140), and a Cable Coupler (#278-304). Connect your coaxial cable to the cable coupler, and then to the first matching transformer. The output is two screws for the old two-wire antenna wire. Your indoor/outdoor matching transformer has two connectors for the screws, and the other end is a coaxial connector. Hook your cable or satellite receiver into this connector and see if the hum goes away.
Here is why this trick works: the first transformer converts your 75-ohm coax into a 300-ohm antenna connector. The second transformer converts the 300-ohm back to a 75-ohm connector. The humming, which usually is at around 60 Hz, can't pass through these conversions.

Ground Loop Hum

The second cause of hum is called a ground loop, and it almost always shows up right after you bring home a brand-new, self-powered subwoofer, or perhaps an external amplifier.
Take a look at all the plugs on the power cords on your home theater equipment. In most systems, the receiver (or amplifier) has a three-prong power plug, but most of your other devices have only two-prong plugs. This is not by accident; the device with the three-prong power plug is grounded. This means that device "owns" the ground. As long as no other power device has a three-prong plug, everything works well.
When you bring home a self-powered subwoofer and plug it in, though, you might notice it has a three-prong plug; this is for safety reasons. However, when you connect an RCA cable from your receiver to your subwoofer and turn everything on, you suddenly notice a loud hum.
The external amplifier in your subwoofer is now fighting with the amplifier in your receiver for possession of the ground. Both devices want to define 0.00 volts. But because the wiring in the two amplifiers to your household AC ground is different, one device is really using 0.001 volt and the other device uses something closer to 0.003 volts. The subwoofer cable connects the two, and the fighting begins.
You have to stop these two devices from trying to own the ground, or get them to not "see" each other. First, make your system produce the humming noise. Disconnect the single RCA cable between your receiver and subwoofer. Did the noise stop? If so, you have a ground loop issue.
The proper, safest way to solve this problem is to buy a special subwoofer cable with little arrows on the wire to show the signal direction (see ).
[img src="http://oreilly.com/images/hacks/htheaterhks/figs/htheaterhks_0601.jpg">
Figure 1. Subwoofer cable with directional arrowUnfortunately, many people have been ridiculed when asking about these sorts of cables at their local electronics store: "But cables don't really have a direction. My expert friend at work laughed at me when I asked about this!" Yes, your friend is right. Cables don't have a direction, but these little arrows indicate that this cable will prevent or solve your ground loop problem.
Remember when I said the hum started when you connected the RCA cable? That RCA cable really contains two wires: the center wire and something called the shield. The center wire carries the audio signal, but the shield tries to define 0.00 volts. The shield is the wire that lets the two different components (the receiver or amplifier, and the subwoofer) see each other's ground, and causes the fight. What if you took your subwoofer cable and disconnected the shielding from just one end? Wouldn't that solve the problem? Yes, it would. This is exactly what a subwoofer cable with little arrows does. The shield is not connected at both ends. The shield has to be connected at one end, for connecting to your receiver or amp, so you should run the cable so that the arrows show the flow from the receiver to the subwoofer.
WARNINGIt is unsafe to use a two-prong to three-prong "cheater" plug on the subwoofer power cord to solve the hum problem. Even if the subwoofer came with a cheater plug in the box, it's REALLY not safe to do. Don't do it.

Sep 01, 2013 | Denon Audio Players & Recorders

1 Answer

Have an older (6 + Yrs) VX-10A model, that's worked fine up until now. I recently moved, hooked up the same stereo and surround sound speakers, which worked fine, but the subwoofer made a loud hum as...


Disconnect the input and see if it hums in the absence of an audio source. A bad audio cable shield or unwisely-routed audio cables will allow entrance of unwanted signals from external power sources, magnetic fields, even dimmer-controlled track lights. Sometimes, simply reversing the orientation of the ac power plug can eliminate humming.

Mar 03, 2011 | Velodyne VX-10 Subwoofer

1 Answer

After a power outage I have a loud hum.


Hi, The Ground Rules Of all the annoyances that can afflict any audio/video home theater or even a simple stereo installation, the notorious "ground loop" may well be the most difficult and persistent one to track down and eliminate. A "ground loop" is caused by the difference in electrical potential at different grounding points in an audio/video system. (All the grounds in an A/V system should ideally be at "0" potential.) A ground loop typically adds a loud low-frequency hum or buzz as soon as you plug in any of various audio or video components, including subwoofers, cable-TV outboard boxes, satellite-TV feeds, TV displays, amplifiers, A/V receivers or turntables. The buzz/hum is a byproduct of the multiple power supply cables and a ground voltage differential within your system and its network of interconnecting cables.

Here are some methods to help you get rid of ground loops. Try these first and don't waste money on a power "conditioner" which, in most cases, won't help. (There is no need to "condition" the AC power for your system. Your receiver or amplifier already has a power supply with its own filters and transformers. No further filtering is normally required.)

If you get your system up and running and hear an audible buzz or hum, the first culprit to look at is either the powered subwoofer or your cable-TV or satellite-box feed at the entry point to your system.

First, the subwoofer: unplug the coaxial cable that connects to your powered subwoofer to see if the ground-loop hum disappears. If it does, it's likely coming in through your cable/satellite TV feed.

Reconnect your subwoofer's coaxial cable from the subwoofer input to your receiver's subwoofer output and disconnect the cable-TV feed (or satellite feed) from your outboard set-top cable box or satellite tuner. Be sure and disconnect the cable before any splitters. Now see if the hum/buzz from your subwoofer stops.

If that eliminates the hum, you can install one of these inexpensive in-line ground isolators from Parts Express or Bass Home. Note that these transformer-based ground isolators will work fine with analog cable-TV feeds, but depending on their design they may interfere with or block reception of HDTV signals via a digital cable or satellite dish feed.

Install the ground isolator between the cable-TV feed and the input of your outboard cable-TV box or satellite tuner (or the TV display's antenna or cable input if you have a set with a built-in TV tuner or a cable-card ready set). In many cases, the ground isolator will "break" the loop and remove the annoying hum or buzz by isolating the TV-cable ground.

If a hum remains with the TV cable completely disconnected from your system, or you don't want to risk degrading reception of HD signals from a cable or satellite system, then you may have to add a ground isolator like this Radio Shack Model 270-054 between the line-level coaxial subwoofer cable from your A/V receiver and the line-level input jack on your powered subwoofer.

In all cases, if your subwoofer has a ground-lift screw like some of Axiom's subwoofers, try first removing the screw (or replacing it) to see if it increases or eliminates the hum. It may or may not make a difference.

If you do not have easy access to the aforementioned ground isolators, here are a few more tips:

Try plugging the subwoofer into a different AC outlet in the room, one that isn't supplying power to your components (A/V receiver, TV, cable box, etc.). That might fix it.

Try reversing the AC plug for your A/V receiver or the powered subwoofer. If it's a 3-wire plug or a polarized plug, which has one prong wider than the other, you won't be able to reverse the plug. For safety, do not use a "cheater plug" to bypass the 3-wire plug.

With the power OFF, reverse the AC plugs one by one of any other components that have a standard 2-prong AC plug that isn't polarized. Each time you reverse a plug, turn on the system with the attached component and your subwoofer and see if the hum disappears. In some cases, reversing one or more plugs will eliminate the hum.

If you have a turntable, try connecting a separate ground wire to a chassis screw on your preamp or receiver and see if the hum disappears. If you already have a turntable ground wire, try removing it from the preamp. One or the other may eliminate the hum.

Finally, here is another solution that worked well for a member of our message boards who decided to discard his ground-loop isolator on his subwoofer: "I took off the ground-loop isolator I'd been using and connected a plain 14-gauge wire to chassis screws on the sub and the receiver then powered everything on. Although hum was still there, it was far lower than before. Next I unscrewed the ground-loop screw on the back of the sub and that took care of the hum completely."

Almost certainly sounds like an earth loop to me, but can be caused by a poorly made transformer or phase shifts on the mains supply. Visit some power conditioner web-sites like Isotek or Isol-8 (or google "earth loop") where there's plenty of advice on how to reduce/eliminate earth loops and other causes of mains-induced hum (transformer problems etc).

Hum on the speakers usually indicates that there is a DC voltage on the speaker line. DC voltage on the output lines would be caused by a shorted output transistor.


Have a nice day...

Feb 16, 2011 | Cambridge Soundworks BassCube 12 Speaker

1 Answer

Loud hHum from Subwoofer


Sounds like the hum might be mains hum caused by the failure of the power supply capacitor(s) in the sub. It/they will be the largest on the pc board. You will find all the details (needed to replace it) on them. If you find more than one replace both.

Dec 10, 2009 | Audio Players & Recorders

1 Answer

Carver d12 subwoofer making humming sound


check your rca ground on the woof or the receiver you have a bad ground on one

Oct 09, 2009 | Electronics - Others

2 Answers

Bought a used Martin Logan Dynamo subwoofer a couple days ago and have a very loud hum when the ac cord is plugged in, even if the speaker is not connected to an audio source. The "hum" can be heard in any...


Neither the amp or the sub have grounded power cords.

I have discovered the ML Dynamo takes about 30 minutes to switch to standby in auto mode.

With speaker level inputs connected to the Onkyo A807 amp, both units powered from the same wall outlet, Dynamo sub on Auto, the sub hums for about half an hour after the Onkyo is switched off, then the sub goes quiet. Not so good.

I connected a bonding wire between the two units on 3_7_09. If I smoked some old audio gear I could just look at that as an opportunity, right?

Works fine. Now I have the ML powered from the wall and working normally.

Jun 30, 2009 | Dynamo MartinLogan Subwoofer Speaker

3 Answers

Loud humming buzzing sound coming from subwoofer


make sure you have the speaker connection right if you do then it is a ground problem try plugging it in a different outlet

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