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Looking at the boards I came across this post: http://www.avsforum.com/avs-vb/showt...threadid=85912 and I started to wonder.


At my last hearing test the tech told me that my hearing has started to roll off around 18KHz. She said this was "normal" and will only get worse over the next 40 to 50 years. (Assuming I live that long.)


So what is the high end limit of your hearing? Anyone been tested recently? What about "super tweeters" Are they good for anything other than annoying the hell out of my dogs? :)


Why have a recording (SACD) that contains sounds that no human can hear? I don't buy the "ultra high harmonics contribute to the music" theory.
 

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James Boyk has done some studies showing that while we don't "hear" them, ultrasonics affect our perceptions.


Do a search on his name and maybe Caltech and you'll find the relevant info.


It isn't just about "hearing" per se, it is also about Intermodulation effects as well.


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I tested the high frequency limit of my hearing in a university psychoacoutics lab where I worked in college. I could hear up to about 18.7 kHz at age 20.


The strangest thing about it was that at the highest range, I couldn't actually hear a tone per se, but I knew if the tone was present. But above my limit I could not tell. So either way, perception of a tone or detection of a sound can't be done above your highest limit.


I also noticed that each time I tested over several days, my limit increased slightly.


The test was in a double soundproof room (one inside another) using calibrated earphones. The computer would turn on a light, play a tone (or not), then adaptively adjust the frequency up or down depending on whether the answer (pushing the yes or no button) was correct.


Same thing happened with testing the lowest detectable volume - 1 dbA - couldn't hear it but knew it was there, but only after practicing a few times.
 

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I was able to detect sine waves up to 21 kHz when I was in my twenties. I'm now 45 and only good to 18 kHz and my sensitivity at 15,750 Hz is not what it once was. I work in a television station and am no longer constantly annoyed by the flyback noise on the many small monitors that we have (the horizontal sweep rate of NTSC is 15,750 Hz.)


I underwent a standard hearing test just two weeks ago due to a concern I had over what turned out to be an open eustacian tube behind my right ear as a result of flying cross-country while suffering from a head cold (something I knew you're not suposed to do.) My hearing test (which they only do from 250 Hz to 7.5 kHz) is normal and I have been assured that the sensation of pressure that I feel behind my right ear and the alteration in the sound of my own voice that I hear will go away as my head cold symtoms subside. At some point the eustacian tube will expand and contract normally in response to ambient air pressure and everything will be normal again.


Males gradually lose their ability to hear high frequency sounds due to a gradual loss of the tiny hairs in our inner ears that resonate at frequencies above about 8 kHz. Females tend to retain most of their high frequency hearing through advanced age. I don't consider such gradual loss to be much of a tragedy. I would describe what Rush Limbaugh is currently experiencing as "tragic." He has lost 100% of his hearing in one ear and 80% loss in the other since May, and might have to undergo cochlear implant surgery, which may or may not help him out. He is currently able to talk to guests on his show by utilizing voice recognition technology. A team of experts is currently evaluating his situation in an attempt to determine the cause of his hearing loss and attempt treatment. If you listen to his show and wondered why he sounds different now, this is why.
 

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Speaking of top end hearing. Does anyone know what frequency a tv generates when its on? The tv can be on mute, but I can always "hear" a tv when its on. Its this high pitch whine, some other people can hear it to. I can hear a tv that is on from the next room.
 

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Fecund,


You must not have read careful David McRoy's post where he clearly states that the NTSC horizontal sweep frequency is 15.75kHz.


That is the likely source of the sound you hear.


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I saw an ENT and had my hearing tested by an audiologist about 3 weeks ago due to increasing intermittent tinnitus. I had lost a little sensitivity in the normal test range (up to 8K) in the right ear only. However, they pushed my test up to the limit of their equipment (12K) and my sensitivity rolled off sharply in both ears between 8K and 12K. They had never tested me above 8K before so it is unknown how much change there has been in that area. However, at 8K and below things seem to be pretty stable except for the slight loss in the right ear. On the speech recognition test I scored 100%. During the hearing test I was not experiencing the tinnitus. But it started to kick in while talking to the doctor 15 to 20 minutes later. If the tinnitus would have been present during the test I'm sure at least some dip would have been present in some part of the spectrum at and below 8K.


I'm 49. During my youth I spent a lot of time driving a tractor on the family farm. Loud noise for extended periods of time. Not good.


Dale
 
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