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  1. #1
    Da Dragonball Kid L.J.'s Avatar
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    Subwoofer Hum...Help

    Came home a few months ago with a different cable box(DVR) and a hum started coming from my sub shortly after. I can manipulate the hum by messing with the coax going into the cable box. It just pops on whenever and I can lower it by twisting the cable around. I can get rid of it completely by untwisting the cable partially off the box. I was fine with this til I noticed certain channels were coming in choppy.

    I tried plugging the sub in a different outlet and using a cheater plug on both the sub and then the box. The hum is still there. If anybody can offer some help, I'd appreciate it.

  2. #2
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    Hum

    Sir, since it started with the new DVR I suggest you contact your cable provider. I suspect that your cable system is not properly grounded. I know how annoying that hum can be, good luck.

  3. #3
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    LJ, good to see you grace us with your presence again Is it possible to try a new piece of cable from wall to DVR? Maybe the connectors worked loose when switching out or something. Another thing I'd try would be a filter product that offers a in/out for CATV.

  4. #4
    3LB
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    cunning linguist 3LB's Avatar
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    a subwoofer hums...

    when it doesn't remember the words
    Repost this on your wall if you love Jesus.

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    Rim Shot!!

  6. #6
    Suspended Smokey's Avatar
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    Quote Originally Posted by L.J.
    I can get rid of it completely by untwisting the cable partially off the box.
    That is exactly where the problem is. Your cable’s ground (assuming it is grounded properly) does not match house ground in term of voltage, so there is ‘hum” current flowing from higher ground voltage to lower ground voltage.

    That is a very common problem which I also suffer from. There are couple of cures. First one would be as Mr Peabody mentioned is to insert a filter into Cable or IC audio path to break the hum current. They are available at radioshck and are called Ground Loop Isolator for $17. It take place of IC from amp to sub, or from cable box to audio components.

    http://www.radioshack.com/product/in...ductId=2062214



    Another solution which I use is to separate video system from audio system electrically. Which mean any components that are connected to Cable box will not have any (audio/video) connection to audio system.

  7. #7
    Da Dragonball Kid L.J.'s Avatar
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    Ok I will give those suggestions a try if Comcast says everything is grounded properly. I'll report back once I get this thing figured out. Thanks

  8. #8
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    Something else to consider is your home's wiring! Try plugging your sub amp into another part of the homes wiring. If your running everything off the same circuit, it can also cause a humming! Start with the obvious and work into the not so obvious!

  9. #9
    Man of the People Forums Moderator bobsticks's Avatar
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    Quote Originally Posted by Smokey
    That is exactly where the problem is. Your cable’s ground (assuming it is grounded properly) ...
    ...and that's a big assumption. I've never had a problem with speaks/subs but this problem happens frequently with guitars when the input receptacle's wires become detached/frayed. They also display the same dealio in which you can manually "reconnect" the complete chain by movin' stuff around. Check the input on the sub itself.
    So, I broke into the palace
    With a sponge and a rusty spanner
    She said : "Eh, I know you, and you cannot sing"
    I said : "That's nothing - you should hear me play piano"

  10. #10
    Da Dragonball Kid L.J.'s Avatar
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    Problem Solved!!!

    I checked out my outside cable box and noticed that the ground wire wasn't connected to anything. Turns out it snapped at the end that was connected to the ground rod or whatever it is. I could see the other piece connected to the screw. I just stripped the end, reinserted it and tightened the screw back up. Baam! No more hum.

    Thanks for pointing me in the right direction guys!

  11. #11
    Forum Regular harley .guy07's Avatar
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    Good deal. I figured it was something simple since I have plenty of equipment and I have always been able to trace down problems like this just by tracing back the signal and grounds.

    Marantz SR5008(HT)
    Nu Force P8 Preamp (2 channel)
    Pass Labs X150.5(2 channel)
    Adcom 545 mk2 power amp(rear channel amp)
    Spatial Audio M3 Turbo S Mains Speakers
    Dayton 8" HO custom sealed subwoofer(2 channel)
    Yamaha NS-c444 center channel
    Emotiva ERD-1 surround speakers
    JBL e250p subwoofer highly modified
    Samsung 46" LED TV
    OPPO BDP-83 blue ray/multi format player
    ps-audio NuWave dac (2 channel)
    Dell I660 music server running fidelizer windows 8 audio optimizer
    PS Audio Quintet power center



  12. #12
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    Ahhhh

    I love the smell of a freshly solved question in the morning... smells like VICTORY!!!!!

    Glad they helped you out LJ

    Worf

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