Problem with sub: annoying hum.

Discussion in 'Archived Threads 2001-2004' started by Andres Munoz, Apr 16, 2002.

  1. Andres Munoz

    Andres Munoz Cinematographer

    Joined:
    Dec 21, 1999
    Messages:
    2,489
    Likes Received:
    0
    I have two subs. A 12" Kenwood and an 8" Atlantic Technology. My receiver is the Outlaw Audio 1050.

    Since the 1050 only has one sub output, I'm using Y adapters to feed the LFE signals not only to the two subs but also to two RCA cables which in turn go into an old receiver's CD inputs that power some bass shakers.

    I noticed this hum coming out of both subs a few weeks ago. It's becoming very noticeable lately. Before it was only during quiet passages or when a show was paused (I have Dish Networks' Dishplayer PVR). But now I can hear it all the time.

    The hum goes away when I disconnect the RCA cables which tells me that the problem is not an internal one from the subs.

    Any suggestions on how to get rid of this hum?
     
  2. Saurav

    Saurav Cinematographer

    Joined:
    Feb 15, 2001
    Messages:
    2,174
    Likes Received:
    0
    If you're using directional cables with arrows marked on them, try reversing them. I'm not kidding, this has been known to fix hum problems in the past. If you have a cable connection coming in anywhere into your system, try disconnecting that. If neither work, try unplugging one component at a time between your 2 subs and the bass shaker receiver and see if you can find the component that causes the others to hum. If you're willing, try experimenting with lifting the ground on one/some components using cheater plugs. Are they all plugged into the same power strip/outlet? Different outlets? Try changing that configuration to see if it makes a difference.

    You seem to have a ground loop hum, which happens when a path gets set up from ground, through some components, back to a different ground (or something like that, to put it very simplistically). Often the ground for the cable coming in to your HT is different from the power supply/earth ground that you plug things into. Since everyone's configuration is different, there's no easy way to predict what will cause the hum to go away.

    If you find that doing any of the above makes a difference, people can then suggest ways to make that change permanent without risking electrocution or adding inconvenience to the setup.
     
  3. Andres Munoz

    Andres Munoz Cinematographer

    Joined:
    Dec 21, 1999
    Messages:
    2,489
    Likes Received:
    0
    I'm not using directional cables for the subs. Since the cable run is pretty long (over 30 ft) I'm using RG6 coax cable with F connector-to-RCA adapters. So I don't think I can do anything about that.

    But I will check the other components. They're all plugged into a Monster Surge protector. I will try to unplug one at a time and see what happens.

    About the cable connection coming into the system, I have satellite. Do I disconnect the coax cable going to the Dish Network receiver?

    Got some tracking to do. Thanks.
     
  4. Saurav

    Saurav Cinematographer

    Joined:
    Feb 15, 2001
    Messages:
    2,174
    Likes Received:
    0
     
  5. Barry Barnes

    Barry Barnes Stunt Coordinator

    Joined:
    Mar 31, 2002
    Messages:
    85
    Likes Received:
    0
    Sounds like a ground problem. Could be a bad RCA cable or a ground loop in the wall power socket. Try unplugging one RCA at a time and see if the problem disappears. Sometimes a plug adapter put on the power plug from the subwoofer to the wall can lift the ground and get rid of the hum if that happens to be the culprit.
     
  6. Andres Munoz

    Andres Munoz Cinematographer

    Joined:
    Dec 21, 1999
    Messages:
    2,489
    Likes Received:
    0
    I'll try a cheat plug from Radio Shack. Maybe that'll do the trick.

    Thanks.
     
  7. Brian Nichols

    Brian Nichols Auditioning

    Joined:
    Apr 8, 2002
    Messages:
    6
    Likes Received:
    0
    I just had this exact problem with my SVS sub and I have RG6 with RCA converters as well. Turns out the converter on the back of the receiver wasn't tight enough. Get 2 pliers and really tighten the rca converter tightly onto the f end. That took care of it for me. Hope this helps.
     

Share This Page