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Thread: Project M2 DIY Thread

  1. #16
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    Sadly, this is the most technical info. I was able to dig up. I was not able to find the pending patent docs...

    https://www.youtube.com/watch?v=sIc2ORiDxrE

  2. #17
    Member Fitero's Avatar
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    Thanks for the responses.

    Since this is a proprietary design for JBL, they won't sell the ports either. No matter, it is still a venturi, and can be easily copied by enterprising DIY people.

    All we need is for someone to take a snap-gauge and caliper and measure the smallest part of the port, and the o.d. of the inner port bell and we can do the rest.
    Valentin has already kindly measured the length, which more or less coincide to the data on the M2 tech sheet provided by 4313b.

  3. #18
    Senior Member grumpy's Avatar
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    Or buy whatever flared ports you like and tune to length appropriately

  4. #19
    Senior Member Hoerninger's Avatar
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    Us 7,890,312

    Method for predicting
    Loudspeaker port performance and
    optimizing loudspeaker port
    designs utilizing bi-directional
    fluid flow principles

    AES_PortPaper:
    http://koti.kapsi.fi/jahonen/Audio/P..._PortPaper.pdf
    ___________
    Peter
    Attached Images Attached Images

  5. #20
    Senior Member 1audiohack's Avatar
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    Well the M2 HF protection network comes with a small surprise.

    ATTACH]68669[/ATTACH]

    The cap values are 3.3µF and 4.7µF.
    Attached Images Attached Images  
    If we knew what the hell we were doing, we wouldn't call it research would we.

  6. #21
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    Quote Originally Posted by 1audiohack View Post
    Well the M2 HF protection network comes with a small surprise.

    ATTACH]68669[/ATTACH]

    The cap values are 3.3µF and 4.7µF.
    That's one VERY expensive network. Kudos to you for spending the money to find out the actual values.

    Don't forget to charge-couple them! If they are in the path of the signal then they are in the signal path.

  7. #22
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    Maybe he'll turn up with some of those ports next

  8. #23
    Senior Member JuniorJBL's Avatar
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    Who is this masked Audiohack maniac!!

    Nice job!!
    Always fun learning more.......

  9. #24
    Senior Member 1audiohack's Avatar
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    Hi All;

    I thought that since JBL did such a bang-up job with the M2 that to start out at least I should start with this little network in just to be sure I had the top end right.

    I am going to depart from the design with a 4435 type cabinet and four 2216's. I just like the form and two 15's close coupled gives me the sound I love. I have one but still have to buy two more I-Tech 5000Hd's, ouch! At first I will likely just run the woofers on a DBX260 and a pair of non DSP amps.

    I ran the drivers on the PWT and they are pretty well matched and have consecutive serial numbers, two nice surprises. The top curves are direct drive and the lower two are with the M2 network in series. The network pads the driver down 9.2dB from 3kHz on up and is down 12 dB by 250Hz.

    I can't wait for Christmas break to build cabinets!

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    If we knew what the hell we were doing, we wouldn't call it research would we.

  10. #25
    Senior Member 1audiohack's Avatar
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    If we get some complete geometry on the ports, since they are flat panel mounted we could make those easily from aluminum bar.

    The Everest port and terminal panel? That one is going to be a challenge.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  11. #26
    Senior Member pos's Avatar
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    Quote Originally Posted by 1audiohack View Post
    Well the M2 HF protection network comes with a small surprise.


    The cap values are 3.3µF and 4.7µF.
    Hi Barry,
    Thanks for the confirmation!

  12. #27
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    Quote Originally Posted by 4313B View Post

    Don't forget to charge-couple them! If they are in the path of the signal then they are in the signal path.
    Anyone having a good link for a description of how to do that?
    (I might be interested in trying it for my 68uf protective cap, just for fun, if it does not change phase behaviour or something like that.)

  13. #28
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    Quote Originally Posted by 1audiohack View Post
    I am going to depart from the design with a 4435 type cabinet and four 2216's. I just like the form and two 15's close coupled gives me the sound I love.
    Wow, cool project!

  14. #29
    Senior Member Hoerninger's Avatar
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    Quote Originally Posted by bubbleboy76 View Post
    Anyone having a good link for a description of how to do that?
    Study the circuit
    ____________
    Peter

  15. #30
    Senior Member macaroonie's Avatar
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    Something on this page should get the port issue sorted

    https://www.google.co.uk/search?q=Fl...w=1024&bih=650

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