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The importance of frequencies above 10K when designing speakers is?

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  • The importance of frequencies above 10K when designing speakers is?

    My hearing is generally fine but cuts off at 10K. Most forum residents are above 40 years old and most audiophiles at least that. According to the brief research I've done, the average male 50 year old finds 12K inaudible and the average 40 year old had a hearing loss of 12db at 4K. That is not a typo, the average 40 year old male has a 12db hearing loss at 4K compared to what he could hear as a teen.
    Also, as I understand it, the amount of content in frequencies above 10K is very low compared to that of the total frequency band in most music. Because "bat eared" teen agers are capable of descriminating the presence or absence of tones of 18 to 20K, should we speaker builders go to significantl effort to make our speakers " flat" in the 10-20K range?
    Despite all this, there is no doubt that we (experienced listeners) can easily notice what we percieve as major differences in realism and sound quality of the speakers we build and the way they sound when we alter the FR between 40 and 10K in our crossovers. Floyd Toole emphasizes the importance of flat frequency response and bass in the subjective rating of speaker quality, but to my memory, does not consider the relative importance of the 10K and up frequencies.
    I would love to hear from forum builders and designers with various amounts of known high prequency hearing loss as to how much importance they place on what is going on in the 10K up band. I would also love to hear from any resident who can detect frequencies of 12K or higher, about their perceptions of speakers that are either quite high or low in the 10K and up band.
    I can only hear frequencies of 10K and below, but I can judge a speakers sound quality partially by the nature of the "shimmer" on cymbals or the tone of high notes on a violin, but I'm not sure if these qualities have more to do with other speaker characteristics than frequency response.
    I am not suggesting that we should ignore the 10K up band, some residents are building speakers for their teen children after all, but it might be interesting to ask some young folks to describe the differences they hear between a speaker of known frequency response where you use equalization to supress or exagerate various frequencies above 10K.
    Your thoughts on this topic are of considerabe intrest to me and could be informative to others, please chime in.

    Best regards,

    Jay

  • #2
    I think you've answered your own question.

    Try this with some PC software or DSP. Make a high q filter, add 5-10dB gain and move the center frequency around in the high end, then do the same with 5-10dB of cut. Do this with your favourite music with high frequency content, symbols and such. This should give you some perspective on what frequency bands sound like in music content when they are overly accentuated or missing. You may be surprised how little is going on above 12kHz.
    "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
    exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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    • #3
      I suspect that the fact that the tweeter does not drop sharply at 10K may be more important than the actual sound above 10K. The change in frequency possibly causes audible phase shifts which may be very audible. This could explain why extended response sounds good even if we are technically not able to hear it.

      Cymbals have a lower fundamental frequency than you may think, I looked this up recently and cymbals resonate from 1 to 5 kHz, if I recall correctly. There are certainly harmonics at multiples of this frequency which add to the realism of the sound. Maybe if the the fundamental and the first harmonic are reproduced accurately, is this enough? How many harmonics do we need for realistic sound? I do not know the answer to this question.

      I have a pair of full range drivers that start rolling off at 9-10 KHz and yet the cymbals sound very realistic to me. There is however a slight dullness to the high end when compared to traditional speakers. Adding a tweeter has not improved the overall sound as of yet, but I plan to keep trying.

      Interesting topic!

      Comment


      • #4
        I'm 70, I can still hear 12kHz clearly. A few tweeters roll off that low, but there's no reason to search them out, having 15kHz response isn't going to hurt anything. Where full range drivers are concerned you may find axial response to 10-12kHz adequate, but off axis not so much. The more pertinent question for listeners of all ages is whether having response to higher than 15kHz is beneficial. For the most part it's not. That won't stop the 'Golden Ears' from insisting that they need 20kHz or higher, preferably higher, but those guys will believe anything.
        www.billfitzmaurice.com
        www.billfitzmaurice.info/forum

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        • #5
          Billet touched on some of the things I would bring up in a discussion on that top octave above 10k. I have retained much of my hearing in that range and easily identify 17k tones. I haven’t done any recent testing specifically out to 20k but I recall there being enough meat there for me to hear it just fine.

          Anyways, listening to several different designs of my own and another local speaker nut in just the last year, there is a sparkle that is missing when that octave is not well represented. It sounds dull even if vocals are done well. To me, it’s similar to the way sound changes when us have a head cold. A flat or gentle slope downwards from 10 to 20k has given a smooth and relaxed sound, while the opposite can give a brighter sharper sound, IMO. I suspect, as has already been pointed out, there are harmonics at play that give a sense of space and realism and that when the top octave is ignored, that can suffer. (KinD or similar to infrasonic bass - you may not hear it, but it certainly contributes to the sound; and I’m not just talking about FX laden action flicks) I even feel that some tweeters, like the DQ25, have issues beyond 20k that, while not audible, can contribute to the - for the lack of a better term - listenability (.?) of a speaker. I haven’t ever been able to enjoy a design using that tweeter, including Zaphs. Something about is fatiguing and annoying and grating to me even when I can’t find it in the measurements.

          The 4K to 8k region seems to give a lot of energy to the music and for me can make things sound shouty or glaring like small children shrieking when there are peaks in that region, even when only a couple dB.

          I don’t claim to have golden ears but I do love listening to music and enjoy being invited over to a friends to hear the latest iteration of a design to try and pick out what has changed. Those are my observations. So, in short, I don’t ignore it. Even though it

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          • #6
            The icky DQ25 has issues, I agree! Rory heard it too, and speculated it's related to broadband HD, not just a freq here or there.

            I'll be investigating ultrasonic breakup on a near future project and see what hearing/measuring does with/without.
            I'll be inquiring younger ears' help to see how audible.

            Later,
            Wolf
            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

            *InDIYana event website*

            Photobucket pages:
            http://photobucket.com/Wolf-Speakers_and_more

            My blog/writeups/thoughts here at PE:
            http://techtalk.parts-express.com/blog.php?u=4102

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            • #7
              Originally posted by Wolf View Post
              The icky DQ25 has issues, I agree! Rory heard it too, and speculated it's related to broadband HD, not just a freq here or there.

              I'll be investigating ultrasonic breakup on a near future project and see what hearing/measuring does with/without.
              I'll be inquiring younger ears' help to see how audible.

              Later,
              Wolf
              Count me in! I’m interested in what you find out.

              Comment


              • #8
                I find that the Tinnitus that I picked-up 10 years ago had reduced my ability to hear well.
                I am well over 50 YO.

                Try taking a Zinc supplement daily for about two weeks and see if your hearing improves at all.

                Mine did but I am not sure of the frequency response changes after doing-so. (I had not considered it before-now).

                Just like my vision improves if I remember to eat at least one raw carrot a day, every day for a week and keep doing it every day.

                We change as we age and chasing the more or less stable frequency responses of speakers is probably not a productive pursuit.

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                • #9
                  I'm older and haven't been checked in many years but can hear 20Khz when sweeping a function generator. Those who use dome or ribbon tweeters don't have to worry much about designing for 20K those devices typically operate well at of above those frequencies. Those of us who still like horns, especially 1.4" or larger will see a short fall above 10K without EQ or help. Using the Faital Pro 1.4" the RTA showed a definite rolloff above 6K. EQ was fine but a ribbon was a much better improvement and nice sonic match.

                  I don't see a reason to ignore the upper most octaves and it's easy to choose devices that simply work well without extra effort or engineering.

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                  • #10
                    Here's a LINK to my google drive to download "SineGen", a nifty app to check speaker (or hearing) frequency response.

                    Select a frequency with the slider, or click a musical note, or type in an exact value upper left. Hit the power button and a sine wave will appear in the lower right "offset" box showing it's on), Adjust the output with the Level control and your good to go. You can use the slider to change frequencies while it's on.

                    It doesn't "install" on windows, it just runs when you double click it's icon (in whatever location it resides on your PC after the download or after you move it).

                    I've never had any issues with malware, ads or anything from this app. I know Tom Zarbo has used it as well.

                    Enjoy ...

                    Click image for larger version

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                    • #11
                      IMO even if you cant hear frequencies above 10k the frequencies above 10k can change the sound of the frequencies you can hear.

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                      • #12
                        My music definitely has content above 12kHz. A LPF at 12kHz would suck.

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