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Audio beyond 20_kHz

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  • #16
    Originally posted by Whitneyville1 View Post
    Over a half-Century ago, my hearing was excellent into the 30KHz range. I could pick-out an out-of tune piccolo or A-flat sopranino clarinet by the "beats" with my back turned to the 110 piece symphonic band. War, gunfire and other noise, old-age and strokes have killed my right ear above about 14KHz on a good day, the left will still flirt with 17KHz when I'm not taking blood pressure medicine (yeah, metoprolol and lisinopril play hob with most people's HF hearing, it's in the drug-fact sheet). "Hearing aids" aren't. If you have medium-to-low high frequency loss (say 3Khz to 7 Khz) they may help you understand voices (what they are intended for), but there is no equivalent for hearing like eyeglasses for eyes yet. Enter the graphic equalizer. I can hotten-up my bad frequencies a bit (never more than say +5 dB) and it helps. Strangely, some particular brands/models/designs of tweeters I "hear" better than others, while the graphs show just a 1-2 dB difference at the very most. I'm talking about about three models of Vifas/Tympanites specifically, all excellent squeakers,in well known designs I've copied so go figure.
    I went to a "pop" singers concert last year and she was using a "pitch box" and after less than 20 minutes I was gone. It was in "The Silver Cow Patty" BOK center which doesn't have acoustics...just louder and louder PA, and I couldn't stand it. The phase shift and delay in that hockey rink/basketball arena is bad to start with. Overdrive the mics and that pitch box was worse than fighting cats at 3 AM.

    Ricky-Pooh Inc.
    Sure you don't mean extremely good hearing for a human, into the low 20's?

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    • #17
      I know some here do not believe it, but when harmonic distortion excites tweeter breakup, it in turn effects the fundamentals. IM. The result is increased distortion in the audible range. I know this to be fact. I could reproduce and measure it. It is one of the key reasons where VAS loading compensation is better for some speakers and Miller for others. Method of compensation effects the energy distribution of HD. Of course, the better behaved the tweeter, the less of a problem. The lower the HD to start with, the less of a problem. The better tweeters tend to haver their breakup higher, so less of a problem. Lighter and more rigid domes. Where I had more difficulty was with cheaper soft domes where the mass was higher.

      A LP on the tweeter is not magic, but it can help in some situations. I know that by experience. I have not tried a higher order one. Of course, if your tweeter drops like a rock @ 18 K. then not going to be of any use.

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      • #18
        tvrgeek, when the USAF tested my hearing in 1974 (induction physical) they said I had "outstanding audible response" from 18Hz to 33 KHz (as high as the test went, mainly due to the limitations of the headphones they used). With my glasses, I was "Hawkeye", 10-40 vision. Still have my physical evaluation, as I got in on a "Low physical profile" (no boot camp) due to asthma, with the aid of my US Congressman to pay for college...otherwise I'd have been a "2S" physicalled-out "draft dodger". As long as old man Hershey ran Selective Service, no one single under 28 years of age got a 4F classification until 1976.
        I guess I shoulda joined the Navy and been on a Fleet sub on SONAR. I went to RADAR school since I had already taken Diff Eq's in college. RADAR is based on solving Diff Eq's and I passed top of my class with an S8 (Master Sargent) rating. At School up at Minot AFB, me and the Raytheon guys (instructors) would sit-up half the night discussing (drawing on the mess tables) "stealth" tech theory. I was SUPPOSED to go to Greenland on the DEW LINE, but there was a mess-up on my odors(sic) and I spent about 4 months in SE Asia, more than half the time on hospital ships. The tropics aren't the place to have asthma. 20 meters below the ground in a concrete bunker watching a 'scope in Thule woulda worked. Finally "medicalled" me out from the asthma. "Short timer' with no GI benefits. AKA "Fullbright Baby". Sen. J. William Fullbright pushed thru a bill to stop draftees from going to Germany/Okinawa/Philippines and puncturing their ear drums with a ball point pen and getting out with benefits.

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        • #19
          33K is well beyond "super human hearing" I suspect they wrote it down wrong but I guess nothing is impossible.

          BTW, Active SONAR in in the low Khz. We used SONAR spectrum analyzers for VGC analysis.

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          • #20
            Whitneyville and tvr, a match made in heaven.

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