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Thread: Project M2 DIY Thread

  1. #646
    Senior Member Flodstroem's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    If the originals would fit your design, I would think it’d be cost effective to simply order them from JBL.


    Widget
    Thanks Mr Widget. Yea, I have been thinking of it. But Im unsure about the exact dimension of the original grilles, I havent found any dimension data for the originals. Though I have built the enclosure from the original M2 dimension design (accept for depth)....................
    Also, Im unsure if I can find the mounting female pegs for it? You dont have any dimension data Mr Widget? If not, maybe someone else here reading this owing the original M2 could do some measurements?
    Flodstroem

  2. #647
    Senior Member pos's Avatar
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    What measurements would you need?
    spacing between pins?
    The difficult part to replicate will probably be the matching with the lower part of the horn.

    Regarding the female part, this is the same reference as the S4700 and available from speakerexchange, and if you have a 3D printer it looks ike it is also possible to replicate it using soft material.

  3. #648
    Senior Member Flodstroem's Avatar
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    Quote Originally Posted by pos View Post
    What measurements would you need?
    spacing between pins?
    The difficult part to replicate will probably be the matching with the lower part of the horn.

    Regarding the female part, this is the same reference as the S4700 and available from speakerexchange, and if you have a 3D printer it looks ike it is also possible to replicate it using soft material.
    Thanks Pos. I only need the total Width and Hight (largest) of the original grill. The profile baffle for the two ports are already finished and have the same contour as the resting lip of the WG
    Flodstroem

  4. #649
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    Waveguide and Trandsducer sources?

    I received a parts quote from speaker exchange and am experiencing a bit of sticker shock, anyone know of another source?

    thanks

  5. #650
    Senior Member srm51555's Avatar
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    Not that I know of. I'm finally in the process of getting rid of unused gear so I can purchase another pair of 2216nd's for another project.

    Are you planning on using the D2's? Me and others have had good success using the 2450SL or 2451's. Either way you will be very happy with the results.

    Thanks,
    Scott

  6. #651
    Member Fitero's Avatar
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    Quote Originally Posted by Flodstroem View Post
    Thanks Pos. I only need the total Width and Hight (largest) of the original grill. The profile baffle for the two ports are already finished and have the same contour as the resting lip of the WG
    Height: 450mm at corners to 467mm at centre or lower curve.
    Width: 450mm

  7. #652
    Senior Member Flodstroem's Avatar
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    Quote Originally Posted by Fitero View Post
    Height: 450mm at corners to 467mm at centre or lower curve.
    Width: 450mm
    Thanks Fitero. God to get the dimension of the originals. Looks to exactly fit my M2 clone. Now I have the choice of two alternatives: either purchase the original grilles or make them myself............?

    Anyone here knowing of a god (cheap) source of grilles?
    Flodstroem

  8. #653
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    Quote Originally Posted by Flodstroem View Post
    Thanks Fitero. God to get the dimension of the originals. Looks to exactly fit my M2 clone. Now I have the choice of two alternatives: either purchase the original grilles or make them myself............?

    Anyone here knowing of a god (cheap) source of grilles?
    I did look into making the grills myself, even went as far as drawing it out in the cad software, but in the end decided against the DIY route mainly because I didn't want to use wood and couldn't find any suitable black PVC type material thick enough and available at the time. Matching the curve at the top & bottom is important for the JVC grills to fit vertically and they also have a slight outward curvature which becomes relevant if DIY'ing.

    I made another 3 cabinets after these two but don't have drivers for them yet.


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  9. #654
    Senior Member Flodstroem's Avatar
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    Quote Originally Posted by lesliew View Post
    I did look into making the grills myself, even went as far as drawing it out in the cad software, but in the end decided against the DIY route mainly because I didn't want to use wood and couldn't find any suitable black PVC type material thick enough and available at the time. Matching the curve at the top & bottom is important for the JVC grills to fit vertically and they also have a slight outward curvature which becomes relevant if DIY'ing.

    I made another 3 cabinets after these two but don't have drivers for them yet.


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    Wow, nice cabinets lesliew. Yes, you are right about the hard job to copy those grilles...... I was thinking of if it could be possible to make them out of GRP though I have done a lot of job with GRP on my fishing boat. But again, I found it very hard to make a suitable mold for that job........ Otherwise it could have been the most beneficially method for to copy those grilles I think
    Flodstroem

  10. #655
    Member sebackman's Avatar
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    D2 polarity

    Maybe this is already covered in this very long thread but I thought I would mention it anyway.

    The D2 (2430K) should be wired with reversed polarity, with the positive lead going to the negative (minus) terminal.

    I mainly deal with 4" driver and they are reversed polarity but I faulty got the impression that the newer drivers with +/- designation instead of Black/Red terminals changed this, but apparently not.

    Same goes for 2453, they are also reversed polarity, ie minus being diaphragm moving towards the throat.

    Please disregard this if already documented.

    Merry Christmas & Happy Holidays to all Lansing fans.

    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  11. #656
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    With respect to driver polarity, I never considered it. On mine, I have the genuine "crossover" board.

    Have you tried reversing polarity and looking at the frequency response about 700Hz?

  12. #657
    Member sebackman's Avatar
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    Hi sguttag,

    Please check on you factory filter to see if the input positive leand goed to the negative terminal on the driver. I would expect so.

    I checked the exploded view on the VTX F127F15 that uses the 2430K/D2 and they use reverse polarity.

    Kind regards
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  13. #658
    Member sebackman's Avatar
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    Posted iTech M2 DSP parameters are not correct for BSS DSP

    With the help of a fellow JBL nerd, we have come to conclusion that the M2 DSP parameters kindly posted earlier in this thread are not correct for BSS DSP units.

    They are probably taken from a Crown iTech power amplifier, which the pictures also suggest, and they are not identical to the BSS parameters.
    Tthe Crown iTech DSP and the BSS BLU-XXX DSP units do not work in the same way and do not use the same set of parameters for the M2 monitors.

    The technicians at BSS also seem to confirm that there are indeed differences in the DSP function between them.

    The correct BSS parameters contain 3 more PEQ's and most of the Q values are different. The are also denominated in octaves as opposed to Q in the iTech settings.

    I have done some measurements on a BSS unit with both sets of parameters and the JBL original macro and the alternative set with additional EQ’s and altered Q values did mimic the JBL macro exactly.

    I do not have an iTech to confirm but I’m pretty sure this is correct.

    I will post the alternative list of M2 parameters for BSS units later today or tomorrow.

    I have also done a full set of measurements (frequency/impedance) using 2451SL/2451Be,2453SL and 2430K on VTX and M2 horn (with and without passive filter) that can be made available if of interest.

    Happy New Year
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

  14. #659
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    As reported in another thread...

    For the M2, the HF driver (D2) is wired IN-PHASE from the input cup to driver via the network.

  15. #660
    Member sebackman's Avatar
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    Hi sguttag,

    Good that you can confirm that. Puls patter from the D2 driver is definitely reverse, ie positive voltage on the minus pole creates pressure at the driver exit.

    In M2 there is a 6db DSP Butter filter and a second 6db passive filter in the cabinet which gives a 12 db electric filter and it is common practice to reverse the polarity of a tweeter in 12db systems to compensate for the phase, so maybe that is the reason also in M2.

    A bit odd that they did not fix that in the DSP if that indeed is the reason.

    Anyway, good to know. Thank you.
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

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