What's that noise??
August 26, 2005 12:24 PM   Subscribe

Why, when a TV is turned on--even in another room--can I detect some kind of buzzing/electronic noise, that many other people around me can't detect?
posted by dead_ to Technology (25 answers total) 1 user marked this as a favorite
Is it a high frequency whine, cause I can hear that from next door?
posted by Pollomacho at 12:26 PM on August 26, 2005

Me too. No one else seems bothered by it. There are some computers here at the office, where I can tell if the guy down the hall has his door open or not. It's a curse. I use LCD monitors at home as much as possible.
posted by RustyBrooks at 12:33 PM on August 26, 2005

I've noticed that too and wondered about that since I was about 10.
posted by kuperman at 12:34 PM on August 26, 2005

You may just have better hearing then them.
posted by delmoi at 12:35 PM on August 26, 2005

I was in a museum in Madrid a few years ago, and there was some multimedia show that included a small TV that was whining something awful. It gave me an instant headache. My wife couldn't hear it.

I chalk it up to variety in the human species.
posted by sohcahtoa at 12:36 PM on August 26, 2005

I remember asking my parents this when I was a kid and getting blank looks. It's all normal. A TV's electronics generate 525 lines * 30 frames per second = 15750 Hz, which is at the upper threshold of hearing.
posted by rolypolyman at 12:40 PM on August 26, 2005

I believe this is related to the earlier question about high-voltage power lines buzzing. Inside CRTs, like computer screens and televisions, there's a transformer coil that ramps up the voltage from the wall. It's wound several hundred times with wire that vibrates at high frequency and thus emits sound. I've heard, but not tried it myself, that one can drip hot glue on the side of the coil to dampen some of the vibration and stop most of the sound.
posted by odinsdream at 12:41 PM on August 26, 2005

It's the flyback transformer.
posted by rajbot at 12:42 PM on August 26, 2005

There was a thread about this on the Something Awful forums once. Most children can hear it, due to having different hearing than adults, and some adults are more sensitive to it than others. So, it's normal for you to be able to hear it, there are many others who hear it(but not all-I don't, even though I clearly remember it from my childhood), but I have no idea WHY you do.
posted by Juliet Banana at 12:43 PM on August 26, 2005

If you're talking about the kind of awful high-pitched whine that lots of electronic devices make, you probably just have better hearing than most other people. The noise from monitors and TVs is pretty bad, but the worst is the noise of the flash charging up on disposable cameras. I can get used to the noise if I'm in a room with a monitor or TV for a while, but I still hear it [and wince] whenever I come in.
posted by ubersturm at 12:44 PM on August 26, 2005

Me too, that and flourescent lights. I can see both them and the TV set flicker. Apparently it's not uncommon.
posted by jessamyn at 12:45 PM on August 26, 2005

I thought I was the only person who experienced this! for some reason, the sound of the whine changes when someone's near. for example, I remember lying in bed as a kid with the tv on and when one of my parents would walk towards my room, the whine would change from a fairly constant pitch to a somewhat erratic pitch.
posted by mcsweetie at 12:45 PM on August 26, 2005

rajbot is correct. It's the flyback transformer, and the noise is right around 20,000 hz (so, the older you are, the less likely you are able to hear it). Ever see a dog's ears perk up when you turn on a television?
posted by Merdryn at 12:48 PM on August 26, 2005

Long ago, I used to win money in HS by taking bets that I could pin point computer monitors that were on.

I would go out of the lab, someone would turn off all the screens except for one (blank - nothing shown), I would be blindfolded. Then I would come back in and unerringly lead people to the monitor that was on. I won $100 easy in $5 bets from people. (In 1989 as a freshman? Serious scratch.)

They even 'invented' double-blind tests, tests where *no* monitor was on, tests where *two* would be on, etc.

posted by unixrat at 12:53 PM on August 26, 2005 [1 favorite]

yeah i figured it was something like that. It's not really a bother to me, just something I always wondered! Thanks!
posted by dead_ at 12:54 PM on August 26, 2005

This has been answered above (it's the 30*525 cycle hum), so I just thought I'd mention that the reason that e.g. unixrat can locate the monitor so easily is that such high-frequency noises don't diffract around your head very well. Hence the amplitude difference in your ears gives you a lot of information about where it is.

I was in a museum in Szentendre, Hungary that had a bunch of boxes making even higher, and much louder, noises. Nobody else could hear them, but eventually they believed me when in every room I could instantly locate an innocent-looking little box and say "That's hurting me!" I suspect it was related to a motion detecting alarm system...?
posted by Aknaton at 1:02 PM on August 26, 2005

Yeah, I can hear the high-pitched TV whine in houses as I go by. I asked my dad about it when I was a little kid and he didn't hear anything (male, at the time 40-something, had spent lots of time sitting in orchestras). I had my hearing tested once in college as part of a science experiment and I had a pretty high range of hearing compared to the average. Come to think of it, though, I've been hearing it less and less as I get older.
posted by matildaben at 1:11 PM on August 26, 2005

I just realized that I can't hear this any more. It used to drive me nuts when I was a kid.

Yay, aging.
posted by ikkyu2 at 1:36 PM on August 26, 2005

Is this the same reason I can hear those pest repellent things that you plug into an outlet that are supposedly silent? My mom has one of those, and it drives me mad.
posted by amro at 1:44 PM on August 26, 2005

I hear electronic noises from lamps, televisions, computers, etc. all the time, and until I read this thread, I thought everyone else could hear the noises as well.
posted by Felicity Rilke at 3:55 PM on August 26, 2005

Damn, I was wishing for super powers and all I got was this ability. I've been able to notice the change of a channel from another room with the sound muted. It was pretty scary there for a while, not knowing how I was the only one who could feel this happening.
posted by Derek at 5:59 PM on August 26, 2005

Yeah, I get this too. The TV is at such a high frequency that it's almost like another sense. I can't so much hear it as feel it (though of course, I am hearing it). I can instantly tell if the TV is on when I walk in the door, even if it's just silently sitting there with nothing on but the DVD player logo.

My dad has an air ionizer in his car, and it drives me crazy - a high pitch whine that he (with an acknowledged lack of hearing) can't make out at all.
posted by tomble at 6:16 PM on August 26, 2005

I'm able to hear it as well. I used to work for a public service publishing and broadcasting organization. I asked the boys up in TV-land if they could hear the tone. Out of eight of them, only one could. Apparently, the tone is about 22 Khz. I can tell if a TV is on in the house regardless of what room I'm in or what floor I'm on. When I lived in an partment building, I could tell, after getting off the elevator, which of the other five suites on my floor had a TV on.

And while my frequency range of hearing is (apparently) good, my acuity is poor and I have tinnitus to boot. Go figure.
posted by solid-one-love at 6:32 PM on August 26, 2005

Yep. Started recently, when my palm tungsten started making said noise. I have since fixed the palm problem, but now I hear the noise everywhere!
Especially in my school's computer lab.
posted by signal at 8:56 PM on August 26, 2005

Kick it. I used to work in a dealing room with 150 monitors. There was one that "tuned" into my ear causing the hi-pitched whine. Every morning I had to kick it and then it would be out of tune for the rest or the day.
posted by priorpark17 at 12:09 AM on August 27, 2005

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