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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Frequency sounds from TVs
Do TVs emit some sort of high frequency sound when they're turned on?
Ever since my parents got digital cable, my dad has a bad habit of turning the cable box off but forgetting to turn the TV off. He can't tell the TV is still on because with the cable off, the TV screen is black and there's no audio coming from the speakers. But I can always tell when the TV's on because I can hear some sort of sound coming from it. My parents say they don't hear any sound coming from it and think I must have Superman's ears. I have no idea how to describe the sound. My guess is that it's emitting a high frequency noise that my parents just can't hear. I suppose it's similar to the sound a fluorescent light makes. Any ideas what the sound is and why my parents can't hear it? I once heard that there's a cellphone or ringtone that only people under 30 can hear. It has something to do with the frequency. I don't know if that's true but maybe that's why my parents can't hear the sound the TV makes. |
#2
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Frequency sounds from TVs
"Jo - the girl" wrote in message
... Do TVs emit some sort of high frequency sound when they're turned on? 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. |
#3
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Frequency sounds from TVs
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. CRT based sets may resonate noises from the power supply, the deflection circuits, and the deflection yoke. Newer sets, when tuned to a high definition signal, may not specifically radiate the 15khz noise because the horiz circuits may be running an a higher frequency rate. As noted, younger folk and women have better high frequency hearing (Unless they have I-Podded their ears too much already!!) than older gentlemen, therefore the noises will be noticed by them long before mose older men will ever hear it. "William Sommerwerck" wrote in message ... "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. |
#4
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Frequency sounds from TVs
William Sommerwerck wrote:
"Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? Sure do. You're hearing vibrations from the horizontal output transformer. The frequency is 15734.25 Hz. 15734.26, but who's counting? 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. 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. |
#5
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Frequency sounds from TVs
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.) |
#6
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Frequency sounds from TVs
William Sommerwerck wrote:
"Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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 |
#7
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Frequency sounds from TVs
jakdedert wrote:
William Sommerwerck wrote: "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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. -- "I'd rather have a bottle in front of me than a frontal lobotomy" "Daily Thought: SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS. http://webpages.charter.net/jamie_5" |
#8
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Frequency sounds from TVs
Jamie wrote:
jakdedert wrote: William Sommerwerck wrote: "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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. I imagine the cost saving came first, and the other effects were simply 'ancillary benefits'.g 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 |
#9
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Frequency sounds from TVs
jakdedert wrote:
Jamie wrote: jakdedert wrote: William Sommerwerck wrote: snip 15 or so years ago, some manufacturers quit putting power indicators on TV sets. snip 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. 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 |
#10
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Frequency sounds from TVs
"jakdedert" wrote in message .. . Jamie wrote: jakdedert wrote: William Sommerwerck wrote: "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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. I imagine the cost saving came first, and the other effects were simply 'ancillary benefits'.g 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 Yep, jak... The crickits I hear often. Even in the winter. Very annoying. Hearing down to about 3000 Hertz now. W W |
#11
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Frequency sounds from TVs
Jo - the girl wrote:
Do TVs emit some sort of high frequency sound when they're turned on? Ever since my parents got digital cable, my dad has a bad habit of turning the cable box off but forgetting to turn the TV off. He can't tell the TV is still on because with the cable off, the TV screen is black and there's no audio coming from the speakers. But I can always tell when the TV's on because I can hear some sort of sound coming from it. My parents say they don't hear any sound coming from it and think I must have Superman's ears. I have no idea how to describe the sound. My guess is that it's emitting a high frequency noise that my parents just can't hear. I suppose it's similar to the sound a fluorescent light makes. Any ideas what the sound is and why my parents can't hear it? I once heard that there's a cellphone or ringtone that only people under 30 can hear. It has something to do with the frequency. I don't know if that's true but maybe that's why my parents can't hear the sound the TV makes. 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 |
#12
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Frequency sounds from TVs
"William Sommerwerck" wrote in message ... "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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 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. |
#13
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Frequency sounds from TVs
"Jamie" t wrote in message ... jakdedert wrote: William Sommerwerck wrote: "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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. 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. |
#14
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Frequency sounds from TVs
Warren Weber wrote:
snip 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 Yep, jak... The crickits I hear often. Even in the winter. Very annoying. Hearing down to about 3000 Hertz now. W W 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 |
#15
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Frequency sounds from TVs
James Sweet wrote:
"Jamie" t wrote in message ... jakdedert wrote: William Sommerwerck wrote: "Jo - the girl" wrote in message ... Do TVs emit some sort of high frequency sound when they're turned on? 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. 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. 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. 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 |
#16
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Frequency sounds from TVs
jakdedert wrote:
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). 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. |
#17
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Frequency sounds from TVs
jakdedert wrote:
Warren Weber wrote: snip 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). Yep, jak... The crickits I hear often. Even in the winter. Very annoying. Hearing down to about 3000 Hertz now. W W I vaguely remember 'hearing' total silence. 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. |
#18
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Frequency sounds from TVs
clifto wrote:
jakdedert wrote: Warren Weber wrote: snip 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). Yep, jak... The crickits I hear often. Even in the winter. Very annoying. Hearing down to about 3000 Hertz now. W W I vaguely remember 'hearing' total silence. 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. 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 |
#19
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Frequency sounds from TVs
wrote in message ... Standard definition CRT TVs make the pitch others have stated at 15.734 KHz. It depends what that 'standard' is! Most of the world do not use NTSC 60. Morse |
#20
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Frequency sounds from TVs
On Dec 22, 8:26*am, "Morse" wrote:
wrote in message ... Standard definition CRT TVs make the pitch others have stated at 15.734 KHz. 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 = 283.75 * 15625 Hz + 25 Hz." GG |
#21
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Frequency sounds from TVs
On Dec 16, 7:00*pm, Jo - the girl wrote:
Do TVs emit some sort of high frequency sound when they're turned on? Ever since my parents got digital cable, my dad has a bad habit of turning the cable box off but forgetting to turn the TV off. He can't tell the TV is still on because with the cable off, the TV screen is black and there's no audio coming from the speakers. But I can always tell when the TV's on because I can hear some sort of sound coming from it. My parents say they don't hear any sound coming from it and think I must have Superman's ears. I have no idea how to describe the sound. My guess is that it's emitting a high frequency noise that my parents just can't hear. I suppose it's similar to the sound a fluorescent light makes. Any ideas what the sound is and why my parents can't hear it? I once heard that there's a cellphone or ringtone that only people under 30 can hear. It has something to do with the frequency. I don't know if that's true but maybe that's why my parents can't hear the sound the TV makes. We can supply many name brand product in different popular designs, sizes and colors.if you need something pleace visit our website find it out or contact us.everything is cheap. website: http://www.longtimetrade.com messenger: longtimetrade01@ hotmail.com longtimetrade02@ hotmail.com longtimetrade03@ hotmail.com longtimetrade01@ yahoo.com.cn longtimetrade02@ yahoo.com.cn longtimetrade03@ yahoo.com.cn www.longtimetrade.com wholesale supply sell replica sport shoes casual shoes handbag watchs t-shirt jeans shirts jerseys sweater belt wallet sunglasses Jewellery Electronics hat cap coat suits shorts etc. product name like the nike adidas DG LV CHANEL GUCCI ROLEX DIOR burberry puma prada bape polo armani versace boss juicy chole coach paul smith omege longines breitling ed hardy ny af bbc lrg ggg iwc bmw rado lacoste nokia iphone etc. |
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