What is that high pitched ring that TV's make?

Discussion in 'Archived Threads 2001-2004' started by Jamerson, Nov 26, 2002.

  1. Jamerson

    Jamerson Auditioning

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    Ok this question is a weird one, but I want to find out if other people have observed this or if I'm just a freak.

    I'm talking about that high pitched noise that can be heard when you first turn on a tv. For me, if a TV is on in my house I can always hear that noise from from at least several rooms away. With most TV's it blends in enough with background noise that it doesn't bother me, but I recently bought a TV that's louder than most, and I'm returning it because of this.

    I don't notice this sound at all on my HDTV. Does anyone know what I'm talking about or am I going crazy? What causes this?
     
  2. Kevin P

    Kevin P Screenwriter

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    It's the flyback transformer, which on a standard TV operates around 15 KHz, near the upper limit of hearing. It causes the electron beam to scan horizontally across the screen, creating the picture. The oscillating magnetic field around the transformer causes it to hum at the frequency it's operating at.

    You don't hear it on your HDTV because it's operating at around 31 KHz, double the frequency of a standard TV and beyond the range of normal human hearing (though your dog(s) or cat(s) can likely hear it).
     
  3. Bob McElfresh

    Bob McElfresh Producer

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    There is a story told in electronics classes about that noise. Some engineers figured out how to stop the sound, but were never allowed to put it into production. The theory was that the sound had a lulling effect which kept people watching TV longer so they could see more commercials.
    (I'm not sure I believe the story. [​IMG] )
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    I used to hear that high pitched whistle all the time when TV sets were on. NOwadays my hearing only goes up to around 13 KHz (actually tested) so I no longer hear it.
    Maybe I really don[t need such a good frequency response on my HT audio system any more.
    As people age, on average they lose the ability to hear higher frequency sounds. Thus the theory about the lulling effect to get people to watch more TV and more commercials would not achieve its goal with middle aged and older folks.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  5. ChrisWiggles

    ChrisWiggles Producer

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    yes OMG this sound is VERY annoying. And as tvs age it seems to get much worse. I actually don't notice it because theres a lightbulb SOMEWHERE in my room that rings lower, but louder. Its very strange, but there are like a dozen incandescant lights, and im just to lazy to figure out which bulb it is. I swear, one day im so lazy, i'm gonna order one of those wave radios, just because i can order it all without getting out of my chair, and i can find the phone number on all the shopping channels [​IMG]
     

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