Speaker Interference

Discussion in 'Beginners, General Questions' started by ChipD, Apr 5, 2004.

  1. ChipD

    ChipD Extra

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    I have a couple questions about some sounds I'm hearing through my stereo speakers.

    1. When I press TV/Video to change my input from my TV to my receiver (to watch a DVD or tape), and before I select the receiver output (DVD or tape), there is a constant low bass sound coming from both of my speakers. Kind of a "brrrrrrrrrrrrrr" rumble. Very deep. The sound gets louder and softer if I adjust the volume. As soon as I select the output source on the receiver, the sound goes away and I can play the DVD or tape (and it sounds great). Is this some kind of interference? The sound only happens in "Video" mode (from TV/Video) before I select the receiver output (watching Tv is also OK). The main reason it worries me is that if I have the volume up when I select TV/Video (or if someone else does it), the "brrrr" sound is extremely loud (and low-bass) and I'm concerned about hurting the speakers. Why is this happening?


    2. Question 2 - I can hear a light hissing/static sound through my speakers when I am watching TV (no problems with DVD). It is very light in the backgroud (can hardly notice with other TV sound) - I can hear it best when there is little sound on the TV or when I change stations (between stations when the screen is black and I can't hear other sounds). I am guessing this is normal interference from the TV or cable hookup, and my speakers are just intensifying the interference. Does this sound right?

    Thanks for the help!

    Chip
     
  2. Cees Alons

    Cees Alons Moderator
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    Chip,

    What you describe looks like something not to worry about too much.

    Probably, when you change input sources, one of the leads isn't connected internally for a short period and a temporarily "open" or not properly grounded input can give that hum (it's the frequency of the power net - 60 Hz in the US).

    Also, the faint hissing on the TV channels may have something to do with transports (e.g. broadcasts) and is not unusual for TV sound off an external channel.

    Hope this helps.


    Cees
     
  3. Wayne A. Pflughaupt

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    No. 1 sounds like a ground loop, especially since you only get it with TV/Video and not other sources. So you have cable TV? That’s usually the source of the problem.

    Regards,
    Wayne A. Pflughaupt
     
  4. ChipD

    ChipD Extra

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    Thanks for the responses. I do have cable TV and my TV and cable jack are plugged in on the opposite side of the room from the receiver and other components. Sounds like I don't need to worry about the noise. Just for future reference, can anything be done to correct the problem (ground loop)?
     
  5. Cees Alons

    Cees Alons Moderator
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    Chip,

    Can you select the receiver source first and then switch the TV? That would circumvent it.

    A possible solution might be feeding your TV and other equipment from the same power outlet (if that isn't so already).
    Are those power connectors symmetric? If so, you could try to plug one of them (e.g. the TV's) in the other way around (switch pins).


    Cees
     

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