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  • Home built speaker help

    Thanks for adding me to the forum.
    I have a question for anyone that has built a sealed enclosure speakers. I have 2 cubic foot sealed 3 way enclosure and I am looking for a replacement woofer. The original woofer is a polydax bextrene 8 inch 8 ohm. I am wondering whether it would be better to port the cabs and go that route than trying to find an accoustic suspension driver that will suit. Any help appreciated.

  • #2
    probably

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    • #3
      Originally posted by Nordlich14 View Post
      Thanks for adding me to the forum.
      I have a question for anyone that has built a sealed enclosure speakers. I have 2 cubic foot sealed 3 way enclosure and I am looking for a replacement woofer. The original woofer is a polydax bextrene 8 inch 8 ohm. I am wondering whether it would be better to port the cabs and go that route than trying to find an accoustic suspension driver that will suit. Any help appreciated.
      Use an enclosure modeling program (e.g. WinISD) to see how your new driver will behave in the box and tuning frequency if porting.

      Then there is the crossover if a passive design.

      If none of the above makes sense - you need to do some reading. Also you can't simply switch out one 8 ohm driver for another 8 ohm. Look at the impedance curve in the data sheet of any driver and you'll see what I mean.

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      • #4
        Ebay occasionally has bextrene drivers, you might luck out and find one there/

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        • #5
          Of course, even if you find Bextrene coned woofers, it's a crap shoot if the T/S parameters are what you need.
          Francis

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          • #6
            True, unless you find the exact model. When I looked there were some Polydax 8" bextrenes with a model number but the OP didn't give us that.

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            • #7
              This might work: https://www.parts-express.com/hivi-m...oofer--297-446

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              • #8
                Originally posted by chrisn View Post
                Those have a huge peak from the metal cone ringing. The crossover will probably have to be modified to squash that.
                Francis

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                • #9
                  I'm not sure how accurate this is, but you could look at this guide under the "Sealed Volume cu. ft." column and see what they recommend.

                  https://www.parts-express.com/resour...election-guide

                  Mike
                  "We're speaker geeks, not speaker nerds. Nerds make money!" Marty H
                  Bismarck, North Dakota
                  My Current System: Jolida SJ502A, Squeezebox Touch, and Carmody Sunflowers
                  My Garage System:Marantz 2238B and Nano-Neos

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                  • #10
                    Can you post a pic of the woofer?
                    A mains
                    The Ventures
                    Open Invit8tions
                    RSR
                    Sound Troopers
                    Acorns
                    442
                    DGBG's
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                    • #11
                      Originally posted by 6thplanet View Post
                      Can you post a pic of the woofer?
                      Polydax Bextrene 8 inch 8 ohm rubber surround woofer. 45 watts i believe. Made in France.
                      Attached Files

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                      • #12
                        This is French version of it. Audax. and original specs.
                        Attached Files

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                        • #13
                          Check out Human Speakers, can't link here, but they have an excellent long throw 8" designed for acoustic suspension enclosures and minimalist crossover designs.
                          Don't listen to me - I have not sold any $150,000 speakers.

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                          • #14
                            Originally posted by johnnyrichards View Post
                            Check out Human Speakers, can't link here, but they have an excellent long throw 8" designed for acoustic suspension enclosures and minimalist crossover designs.
                            I have those in a rebuilt GP 210 with a 10" passive, and they are great for what they are. Glenn.

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                            • #15
                              Link to specs you can actually read:

                              https://en.toutlehautparleur.com/med...B25H-2C9-8.pdf

                              I'd put Dayton's 8" 295-310 in there, along w/a 3" "Precision Port" out the rear (or front, if need be). Make it 10" long (for a tuning of 28Hz).

                              It's sensitivity is within +/- a dB (or 2) of the old driver, and (on 3-ways) only the bottom end really matters (since it's probably crossed more in the 300-400Hz range than in the 2k-3kHz range). That old driver was only rated 25wRMS, and its Xmax only calcs out to 2.5mm. Looks like it had an F3 in the low 40s (w/a Q near 0.7).

                              The new woofer (ported) will go below 30Hz, and has an Xmax of 4.5mm w/a power rating of 60w. It's Xmax-limited to 16w down to 30Hz, whereas the old one was 3w @ 50 and 2w @ 40Hz.

                              Worst case might be that you might have to add an ohm (or 2) extra series resistance (out in front) of the tweeter's and/or mid's pass-filter if the Dayton isn't quite as loud.

                              (What exactly is wrong w/the old woofers?)

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