Grounding and subwoofer hum

Discussion in 'DIRECTV General Discussion' started by freshmanjs, Sep 3, 2018.

  1. freshmanjs

    freshmanjs New Member

    Jan 31, 2012
    Hi all --

    Please bear with me, as I know very little about electrical issues. I have a new home theater system with 2 powered subwoofers. I noticed that one of the subwoofers had an audible hum (not all the time). I tried isolating components to see what might be causing it. If I disconnect the HDMI that runs between my DTV C41 and the receiver, the hum disappears completely.

    I think it might be that my dish isn't grounded properly. Dish is mounted on a metal pole that goes into the ground. The coax goes from the dish to a wiring center in my basement. It does not appear to pass through a grounding block. There is also a small ground (I think) wire attached to one of the nuts on the dish and run alongside the coax to the wiring center. The other end of this small wire is not attached to anything.

    Any suggestions for what I can do to improve the hum situation?

  2. jimmie57

    jimmie57 Hall Of Fame

    Jun 26, 2010
    Texas City, TX
    Connect the non connected end of the small wire to something that is grounded and see if the hum goes away. Sounds like connecting it just got overlooked.
  3. Rich

    Rich DBSTalk Club DBSTalk Club

    Feb 22, 2007
    Piscataway, NJ
    Hummmmmmmmmm...That would drive me nuts.

  4. P Smith

    P Smith Mr. FixAnything

    Jul 25, 2002
    W.Mdtrn Sea
    I think if you'll post the question at Home theater forum you'll get most suggestions
  5. slice1900

    slice1900 Well-Known Member

    Feb 14, 2013
    First of all, you need to determine why only ONE of your subwoofers has hum. How are each of them connected / powered? It doesn't make sense that your satellite dish grounding is the problem when only one subwoofer hums. If the problem is completely unrelated to your audio system, both subwoofers should hum or neither should hum.

    Tracking down audio hums can be a pain. I had an occasional hum on speakers in just one room that came and went and drove me nuts. It turned out the balanced line level audio running via cat5 from a DI box through a cat5 keystone coupler to one of the power amps was responsible - the coupler had a bit of a loose fit so if you tugged on the attached cables = hum. Push them in tightly = no hum. When I figured that out I cured by replacing the coupler with one that wasn't so 'loose'.​
  6. slice1900

    slice1900 Well-Known Member

    Feb 14, 2013
    Another time (this was several years ago) the speakers connected to an amp owned and maintained by my amusement guy (supplies the jukebox and stuff that goes with it in one room, along with a few video games and dart machines) were humming. I kept on him to fix it but he had no idea what the problem was, so it continued for a few months it was very annoying and noticeable at lower volumes. One time I was checking something near it (it is mounted on the wall almost up to the 12' ceilings in a closet, so kind of out of the way) and noticed it was plugged into a cheap surge suppressor that a few other things in that location were plugged into.

    When I plugged it directly into the wall, no hum. Even if the amp was the only thing plugged into that surge suppressor it would hum. I figured it was probably just a bad surge suppressor so I tossed it. A while later I had some odd problems with one of my plasma TVs that turned out was plugged into the identical model, when I replaced it with the Belkin plug-in style I use everywhere else the problems went away.

    I don't know the exact model of the 'bad' surge suppressor, but if anyone reading this is using an RCA brand surge suppressor which has dual coax inputs / outputs and has a light up "plug" on it to indicate when it is working, grounded etc. I strongly encourage you to toss it in the trash :)

    EDIT: here's a picture of it off Walmart's site:


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