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High pitched screech?

  1. Jul 4, 2010 #1
    Does anyone here a really high pitched noise when the TV is switched on? I am referring in specific to LCD TVs (don't know about Plasma TVs). The sound becomes more conspicuous when I'm watching something on mute. This is very disturbing while watching television. What's more disturbing is that nobody else I know seems to hear this noise. Does anyone here hear it? What is it and why is it so annoying? Why is it only I can hear it?
  2. jcsd
  3. Jul 4, 2010 #2
    Oddly enough, I heard what sounded like high picked interference from my LCD TV earlier tonight. Turned it off and back on and it went away. Never heard it before and havn't since.
  4. Jul 4, 2010 #3


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    Yeah I can hear it. Older people aren't able to hear those higher frequencies usually (in fact there was a cell phone ringtone based on this for use in school)
  5. Jul 4, 2010 #4
    I usually notice it for CRT tv's, not so much lcd ones. Its probably faulty power supplies for the backlight.
  6. Jul 4, 2010 #5
    @Blenton and ibnsos
    This is not a fault with one TV or an error with some specific set. Every LCD TV I watch has this same high pitch noise.
  7. Jul 4, 2010 #6
    Yes anirudh, I hear it and it has always annoyed me whenever someone turned a television on or watched television....including myself. Right now I do not own a television and there is none in my home. I think I haven't watched television in four years....and even prior to that it was scarce because of the high pitched sound.

    I'd just like to mention that no one else in my house was able to hear it but me at the time. Even if someone turned on the TV and it was on mute I was able to tell and they were really amazed.
  8. Jul 4, 2010 #7

    Jonathan Scott

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    I suspect you're hearing something relating to the electronics (possibly a miniature transformer) which drives the fluorescent backlight, or a sound from the backlight itself. You could check that by finding one of the new LCD TVs which is lit using LEDs instead to see if that makes a difference.

    The highest pitch that you can hear varies with individuals and generally drops off with age. There are on-line web-sites where you can test your cut-off point, for example:

    http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/" [Broken]

    I'm 54 and the highest one I can hear now is the 12KHz one on that test. My wife can just hear the 12KHz too. My 9-year-old son can hear 17KHz and my 13-year-old daughter can hear 16KHz.

    When I was younger, many TVs had an irritating whistle, which I found was at the horizontal line frequency (here in the UK), 625*25 = 15625 Hz. (At the time, I could also hear the whistle as an identifiable musical note which seemed to match that, which a quick calculation now says should be around a "B" about two octaves above the top note of a piano).

    I've had problems in the past with CRT monitors issuing really irritating whistles, almost a scream, which is especially problematic when it's someone else's monitor in a shared office and they can't hear it. (Fortunately in that case the young lad called out to check it could easily hear it, and replaced it with one that I couldn't hear at all).

    Most of the rooms in our house now either have CFLs or electronic dimmer switches (for bedrooms). The CFLs often seem to go through a nasty whistling phase while warming up, and the bulbs with dimmer switches emit an irritating hum all the time, although it's minimized when they are at full intensity.

    My main hobby is classical music, and I've taken care all my life to avoid excessively loud sounds as I don't like being deafened, even temporarily. My hearing remains very good, both in terms of being able to hear faint noise and to be able to identify and locate it, but it does mean I tend to be very irritated by background noises such as disk drives and fans in PVRs and computers and whistling from my CFL bedside light. I also find I'm irritated by hum from transformers for electronic equipment even when the equipment itself is turned off.
    Last edited by a moderator: May 4, 2017
  9. Jul 4, 2010 #8


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    I didn't hear it until I read this :mad:. Egads it's annoying.
  10. Jul 4, 2010 #9


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    I can just barely hear the 22 KHz on that one. I think I might have a superpower. I could be called "Ears"
  11. Jul 4, 2010 #10


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    Audiophiles would call you "Golden Ears" and call you in to evaluate their $20K audio systems. You might be able to make a few bucks on the side from it. :biggrin:
  12. Jul 4, 2010 #11

    Ivan Seeking

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    The noise is almost certainly generated by the switching power supply used to produce the high voltage, for the lights. I too could often hear fluorescent lights; not so much anymore.

    The power supplies are supposed to be going to switching frequencies well beyond human hearing, so I'm surprised that you can hear this on a new TV.
  13. Jul 5, 2010 #12
    Told you so!

    Hehe. On the other hand, nobody believes I have good hearing. If I'm reading something and you call my name, I don't respond most of the time. This is attributed to bad hearing. :tongue:
  14. Jul 5, 2010 #13


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    Maybe you just have really good focus when you read. Or maybe you hear perfectly well, but don't listen :tongue2:.
  15. Jul 7, 2010 #14
    Maybe the bonus feature on my ears is to be able to tune in to whatever frequency I want to. Especially if it involves tuning out running errands. :biggrin:
  16. Jul 7, 2010 #15
    Funny story (to me at least) related to hearing tests:

    During college, I'm in Navy ROTC (no political replies either desired or required), and get the opportunity to get trained by the Army as a paratrooper during summer break. Cool. But have to get a physical at the local military base first.

    It's finals week. I'm exhausted because I was up the last 48 hours straight cramming and living on pizza and coke. I fail the urine test due to excess sugar spillover. I get the eye tests 100% wrong because I miss the instructions to read bottom to top not top to bottom (Dr says nothing). I flatline the audio test due to falling asleep in the booth after about 200Hz.

    So, just big red marks all over the chart. Carry it to the front desk nurse. She says, "OK, you're done." I say "Oh, but I need that stamped 'qualified for airborne training'." She just reaches over for the stamp, pounds it down on the chart, and that's that. Good to go - LOL!
  17. Sep 1, 2012 #16
    well pretty much every electronic i know has made that sound. TVs are the loudest and also emit it constantly at a lower tone while they run. Air conditioners emit it also but you have a high and low from them. It only seems to happen when they are on. For hearing when i enlisted they did a hearing test and I scored perfect on all up to 38 hz if i recall that was as highest tested. Plasma's I haven't checked out the old box ones and lcd both do it though. The sound to me while they are running is about what a dog whistle sounds like when someone is blowing into them.
  18. Sep 2, 2012 #17
    I'm 29 and I can hear up to the 19KHz one. That one is extremely faint, but it would drive me nuts if it was coming from my monitor or something and I couldn't get rid of it. The 20KHz sound I can hear if I turn my speakers up louder, but the sound it makes is lower pitch than the 19KHz. Actually, after checking again, the 19KHz is lower pitched than the 18KHz. I think maybe my speakers just aren't recreating the sound right. They're about 8 year old speakers.
  19. Sep 2, 2012 #18
    I can just barely hear the ten KHz if I hold the speaker up to my ear with full volume.

    I remember a long time ago when I had a hearing test at the V.A. The tech told me to hold up my hand for as long as I heard the sound. We went through a lot of frequencies. Finally I found myself sitting there holding up my hand for a long long time.

    The tech opened the door to the sound proof room while my hand was still up. He told me the test was over.:bugeye: That was when I first realized that I had tinnitus.

    Take care of your hearing. It has to last a lifetime.
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