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  • donradick
    started a topic GANDI Design Build Thread

    GANDI Design Build Thread

    Hope I'm not violating the terms of use for Tech Talk.
    The driver is NLA, and I'm not posting any links.

    A few weeks, ago another distributor had a closeout sale of Gradient Acoustics drivers of various sizes.
    After a bit of Googling, it appeared that these were well-regarded, if not really great, so I picked a quad of the 4 inch
    mid-woofers in kevlar/paper - the AXT-04

    Another user here suggested a TM with the ND20 and I committed to the design.
    I may use a pair of ND25 tweeters I have, or I may decide to use a better tweeter.
    Early days though, I'll make that decision after I've listened to them a bit.

    Here is the manufacturers info:
    Click image for larger version

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    Last edited by donradick; 09-26-2017, 05:57 PM. Reason: added tag

  • ceiol
    replied
    Looks beautiful!

    Leave a comment:


  • donradick
    replied
    A table saw is pretty much essential for this build.

    Decided to go with Oak veneer and a solid oak baffle.

    Leave a comment:


  • ceiol
    replied
    looking good!

    I'm going to have to pull the trigger on getting a table saw...

    Leave a comment:


  • donradick
    replied
    cutting wood.....

    Biscuit joints top/bottom and sides, rabbet joints front and back.

    1/2 inch BBB pieces

    Leave a comment:


  • ceiol
    replied
    Originally posted by donradick View Post
    I'll also be working up a version of this with a B&G Neo3 crossover, if you are so inclined.
    Initial listening tests with that tweeter were very promising <grin>

    at $85 each, I'm sure they'll be great... but hard for me to pair with a closeout woofer that cost 1/10th of that!

    I'll stick to the SB26 tweeters

    Leave a comment:


  • donradick
    replied
    I'll also be working up a version of this with a B&G Neo3 crossover, if you are so inclined.
    Initial listening tests with that tweeter were very promising <grin>

    Leave a comment:


  • ceiol
    replied
    Looks great! Can't wait to get the slot design of the port figured out and then start building.

    I was lucky enough to buy four of the AXT-04 drivers during the blow out sale prior to MCM closing.

    Leave a comment:


  • donradick
    replied
    Finished the crossover for the SB26 -
    One item of note, the AXT04 really wanted to run full range to 10K, so I had to use 3rd order on it to get it to fall off at 3-3.5Khz as I needed,
    and get the phase match to the tweeter.

    Xsim crossover pic and ART measurement pics.
    Measured plus/minus 1.5 dB from 200 Hz to 18 KHz with a 30dB reverse null. Sounds smooth, detailed, and suprisingly punchy.

    Click image for larger version

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    Click image for larger version

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    Leave a comment:


  • donradick
    replied
    Originally posted by rpb View Post

    Where's the 10k peak shown by the manufacturer? Do you suppose some diffraction effect eliminated it, or did you possibly measure a little off axis?

    It would be interesting to see a waterfall on this driver too. Are there any surprises 45 degrees off axis?
    OK, as requested, FR responses for both samples (on axis 24 inches and 39 inches), and wavelets for both. I'm somehow not inspired to do off axis at this time.

    Click image for larger version

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    now wavelets for both - pretty darn good.

    Click image for larger version

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    Last edited by donradick; 11-06-2017, 05:27 PM. Reason: fix graphics

    Leave a comment:


  • rpb
    replied
    Originally posted by donradick View Post
    Tested the AXT-04 in a proper box with a port.

    Darn guy is totally flat even without a crossover.
    The full range devotees would swoon over this response.

    [ATTACH=CONFIG]n1351073[/ATTACH]
    Where's the 10k peak shown by the manufacturer? Do you suppose some diffraction effect eliminated it, or did you possibly measure a little off axis?

    It would be interesting to see a waterfall on this driver too. Are there any surprises 45 degrees off axis?

    Leave a comment:


  • ceiol
    replied
    that tymphany BC25SC06-04 looks like a great performer -- especially considering the $14 price tag!

    https://www.parts-express.com/peerle...eter--264-1028

    Leave a comment:


  • donradick
    replied
    Originally posted by rpb View Post
    Do you have a waterfall plot for the BC25SC04-6?
    As requested - looks very, very nice. Maybe that's one reason why I continue to like and use this tweeter.

    Click image for larger version

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    Leave a comment:


  • donradick
    replied
    Originally posted by Millstonemike View Post

    I think they made PVC for speaker builders and then discovered it could be used for drainage

    Thought you might want to you might want to use more of the ATX-04 stellar upper band and a ring would match it's polar response higher up and be clean beyond audible (just testing my learning here).
    I think you are correct, the upper end of the AXT-04 is incredibly smooth, and would easily work with a high crossover to an XT25 for instance.
    I used to be intrigued by tweeters that were flat to 30K. Now I'm much more concerned with 2--5K. If I can get that right, I feel like
    I've done a good job.

    Leave a comment:


  • Millstonemike
    replied
    Originally posted by donradick View Post

    test setup, easily change port length.

    re: ring radiator

    Hunh? not in this design.
    I think they made PVC for speaker builders and then discovered it could be used for drainage

    Thought you might want to you might want to use more of the ATX-04 stellar upper band and a ring would match it's polar response higher up and be clean beyond audible (just testing my learning here).

    Leave a comment:

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