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Is this small woofer response very common?

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  • Is this small woofer response very common?

    This is an old early 90's JBL 6.5" woofer I am playing with. Specs say it is crossed at 4.5khz, but that sounded awful high. I measured it and lo and behold, it goes up fairly high and somewhat smoothly. On test tones it does start to beam obviously, but it will do 9,000 hz easily.
    Is this "smooth" of a response very common with a 6.5" woofer?

    This is with NO smoothing at all, running free measured on axis from 6 inches.

    Disregard the lower frequencies, as it is "Open air", not in box.
    Most woofers this size I have heard running free have a lot more break up and do not go nearly as high. Click image for larger version

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  • #2
    Some designed as mids can be smooth up high. I would not say it's common. Up to 4K would be more common imo; Eminence 6C, and RS paper and some Focal woofers
    John H

    SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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    • #3
      Things get "interesting" when the diameter of the radiator exceeds half of the wavelength.
      "Not a Speaker Designer - Not even on the Internet"
      "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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      • #4
        Originally posted by jhollander View Post
        Some designed as mids can be smooth up high. I would not say it's common. Up to 4K would be more common imo; Eminence 6C, and RS paper and some Focal woofers


        Ya, oddly enough this one just looks like a run of the mill, low cost Stamped steel frame woofer, paper cone with some coating all over it.
        Its got a 50 Hz Fs, nothing special.
        It almost looks like the Cheap GRS woofers, but made by JBL

        Odlly enough its not bad at all sounding.

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        • #5
          Still, that looks like easily +/-6dB.

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          • #6
            Originally posted by Chris Roemer View Post
            Still, that looks like easily +/-6dB.


            Yes, I think you are correct of course!
            When I bring it down to 3db per division, it looks a lot less great...lol

            Still amused me at doing this well even.
            JBL crossed it at 4.5 khz, but I think maybe could do better lower for sure.

            I "Hear" very little break up at all, usually woofers this size I have run free are almost unlistenable.

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            • #7
              It's probably designed that way in order to avoid the need for a steep (complicated / expensive) crossover.
              Of course, that means trade-offs elsewhere. Fairly well-behaved paper cone. Probably not too stiff.

              Shawn

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              • #8
                Originally posted by Audion View Post
                It's probably designed that way in order to avoid the need for a steep (complicated / expensive) crossover.
                Of course, that means trade-offs elsewhere. Fairly well-behaved paper cone. Probably not too stiff.

                Shawn

                It has a coil and cap, but no zobel or anything. The original tweeter was some tiny "titanium" thing, that looked very fragile.

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                • #9
                  Originally posted by kevintomb View Post
                  This is an old early 90's JBL 6.5" woofer I am playing with. Specs say it is crossed at 4.5khz, but that sounded awful high. I measured it and lo and behold, it goes up fairly high and somewhat smoothly. On test tones it does start to beam obviously, but it will do 9,000 hz easily.
                  Is this "smooth" of a response very common with a 6.5" woofer?

                  This is with NO smoothing at all, running free measured on axis from 6 inches.

                  Disregard the lower frequencies, as it is "Open air", not in box.
                  Most woofers this size I have heard running free have a lot more break up and do not go nearly as high. [ATTACH=CONFIG]n1331477[/ATTACH]
                  That's a loooooooooong way from what I would call smooth!

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                  • #10
                    Originally posted by rpb View Post

                    That's a loooooooooong way from what I would call smooth!


                    True, ...relatively speaking...lol

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                    • #11
                      The gobbledygook from 1.8K to to 2.5K is likely an artifact of the open air measurement. I would like to see it baffled. I would wager that tjingymadoozlez in that range would disappear and it would be far more flat.
                      .

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                      • #12
                        Originally posted by mzisserson View Post
                        The gobbledygook from 1.8K to to 2.5K is likely an artifact of the open air measurement. I would like to see it baffled. I would wager that tjingymadoozlez in that range would disappear and it would be far more flat.



                        Ya I know its not some lost audiophile woofer, but for what it is, it "Sounds" fairly good.

                        Vocals and stuff, sound surprisingly nice on it, and it has a "listenable" quality I can not put my finger on.
                        I expected bad quality as I got the pair for 10 bucks at goodwill.


                        Will re-measure it and take more time, and do in baffle also, when I get some time tomorrow most likely.

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                        • #13
                          See what happens at 30 degrees off-axis.
                          www.billfitzmaurice.com
                          www.billfitzmaurice.info/forum

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