Frequency sounds from TVs

Sure do. You're hearing vibrations from the horizontal output transformer. The frequency is 15734.25 Hz.

Women tend to have better HF hearing than men, and everyone's HF hearing gets worse as they get older. I used to be able to hear to 20kHz or so, but can now only hear to around 14kHz.

The newer teles, including the Flat Panel Plasma and LCD sets may resonate noises. The power suppliy circuits in these sets run at moderately high frequencies and do resonate noise.

15734.26, but who's counting?

I can still hear the horizontal sweep from most CRT sets, but it's not as prominent as it used to be.

I used to have fun with that. Often with older sets when I'd disconnect my cheater and put the back on the set, the short disconnect would cause the horizontal sweep to go out of lock. Whenever the customer would notice and mention it, I'd just reach for the hold control and put it back in lock, and say, "Better?" It usually amazed them that I could do that without seeing the screen, but the sound was so ubiquitous it was hard not to know when it was off frequency.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

You're hearing the "ringing" caused by the horizontal deflection of the electron beam drawing the picture on the screen. As others have said, it's over 15 kHz, the upper range of human hearing. I can hear it, too; some folks can walk into a room and just tell when there's a TV set on even with the audio turned off. Once I walked into a jewelry store and stopped dead in my tracks because it felt like an ice pick was being pushed into my ear; the store was using an ultrasonic cleaner for their jewelry and a sales clerk said that some people do hear that.

Children in particular are quite good at hearing this. Some people have hyper-sensitive hearing and can hear the deflection of CRT-based VGA monitors, which is over 31 kHz (normal human hearing range peaks at about 20 kHz). I can't hear that but I have a couple of friends who claim they can. (One of these is a woman who is totally deaf in one ear.)

15 or so years ago, some manufacturers quit putting power indicators on TV sets. For the life of me, I don't know why. It sometimes leads me to turn the set on and off--then on again--because I saw no indication that the switch press had any effect before the crt ramped up.

I wonder how much was saved in omitting one led...and how much extra wear and tear on the set was caused by multiple power cycles on each use.

jak

That's called market research! Save using less and cheaper parts. Make it less friendly there by causing users like you for example to shorten the life expectancy of the mechanical parts and inrush current effects placing strain on the border line components in place. You may think that is strange thinking how ever, the off shore engineers actually get paid for thinking up these tactics in hopes of you coming back and buy a complete new unit.

--
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  SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
  THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
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I imagine the cost saving came first, and the other effects were simply 'ancillary benefits'.

I know that one particular monitor I have, got abused this way because the cheap panel switch became intermittent. Without the remote in hand, one could simply not tell whether a switch press actually initiated a power cycle...unless of course, you pressed the switch, waited (at least ten seconds) for the crt to warm up, and if not, pressed again. Since I was using it just for a monitor (no audio connected) this happened fairly regularly.

FWIW, I 'used' to be able to hear the horizontal frequency when I got a round a noisy set. These days, I hear it all the time...whether I'm around one or not (tinnitus).

jak

The 24" Hitachi TV/Monitor I used for fifteen years was similar except that you could hear the distinctive 'chunk' of the power relay when cycling it but that didn't convey any on/off state information; fortunately the horiz. drive components emitted sufficiently powerful audio that in a quiet room I could tell when it was on.

Regards,

Michael

Yep, jak... The crickits I hear often. Even in the winter. Very annoying. Hearing down to about 3000 Hertz now. W W

Jo - the girl wrote: > Do TVs emit some sort of high frequency sound when they're turned on? >

Standard definition CRT TVs make the pitch others have stated at

15.734 KHz. I used to be able to hear it up until my late 30's - and I work in commercial TV.

The irony is that by the time you get old enough to _not _ hear it because of your age, none will exist any more so you'll never know when you lost the high end.

Men tend to lose high frequency hearing more than women but I don't know if it's a sex issue or that guys used to work in louder environments. Loud noise makes the loss worse.

GG

The deflection yoke and inductors in the horizontal circuit are also common sources of this noise.

I almost look forward to when I'm old enough to not hear it anymore, I can walk into a room and instantly tell that a CRT has been left on, not as loud to me as it used to be though, 10 years ago it was awful.

I've been through a few hardware design cycles, it's all about cost, every fraction of a cent counts with mass produced products. They may not care if it reduces lifespan so long as it lasts "long enough", but I've never encountered an engineer who specifically calculated a way to make something fail sooner.

I push the button once and then wait long enough for the CRT to warm up, very rarely does the first press not respond.

I vaguely remember 'hearing' total silence.

I've had this problem since I was a kid. It puzzled me up into my late teens when I recognized it for what it was...spurred by odd results on the hearing test at my draft physical. Reconstructive recollection traced it back to an incident around 10 yo, firing a cheap revolver without hearing protection. (Did anybody use hearing protection back in the 60's?)

Being a 'threshold' issue, it didn't prevent me from a degree of success as a sound engineer, but has become more annoying as I age. Some times it's louder than others....

jak

Me too, for the most part, except when I was in a hurry...passing the set on the way to the couch after a long day. I got rid of one years ago, but I wonder if it would have lasted longer except for this issue. It's one of the criteria (now) by which I select monitors; but I've got another one in the family room, and I'm not the one who usually uses it. I've seen the kids press the button a couple of times, thinking it didn't turn on....

jak

I've had tinnitus tones as long as I can remember. The horizontal sweep frequency isn't one of my built-in tones, though.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

Not me. I remember at age 5, I was in the yard with my mom, and she shushed me and whispered, "do you hear how quiet it is?" I was too young to think about contradicting her, but I wondered why the hell she thought there was anything quiet about all the tones I heard. It was just another noisy day as far as my ears are concerned.

Since that's as far back as I remember regarding hearing, I kinda doubt that it was ever different. It did get considerably louder all of a sudden about five or six years ago, though.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

The 'takeaway' image in my brain is of being in a shallow cave...about eight years old, I guess, listening to the 'deafening' sound of the silence. That was probably a couple of years before.... It's not been completely quiet since then, although, like you, I remember lying awake at night wondering why there were insect sounds in the middle of winter....

jak

It depends what that 'standard' is! Most of the world do not use NTSC 60.

Morse

OK, 625/50 PAL runs 15.625KHz so it still applies.

from Wikipedia:

"The 4.43361875 MHz frequency of the colour carrier is a result of

283.75 colour clock cycles per line plus a 25 Hz offset to avoid interferences. Since the line frequency is 15625 Hz, the colour carrier frequency calculates as follows: 4.43361875 MHz =3D 283.75 * 15625 Hz + 25 Hz."

GG