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Thread: DIY 4344 MKII using Beyma TPL-150

  1. #1
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    DIY 4344 MKII using Beyma TPL-150

    Hi All, I originally wanted to do a 4345 Clone but I decided to try a 4344MKII version first but in a 3 way. I have the 2245's for a 4345 but I will try with the MCM 55-2963's 15" which are supposed to be very close in sound to a JBL 15". I have two pairs of JBL 2123H's and the Beyma TPL-150 is on their way. I have created a xover for these drivers using Xover Pro software and it looks (Graphs) really nice so far and all drivers seem to match up very well. For now I will be using the 15" Knock Down cabinets from Parts Express that I got last week. This should give me a good feel for what this combo of speakers can do. I will be making an enclosure for the 10" to isolate the 10" from the 15" woofers like in the 4344 and will set the Beyma 150 on top of the cab. I ordered the TPL-150 without the horn so I can get a wider dispersion (120 degrees horizontal) than with the horn (80 degrees). Hope this will work out.

    I still need to get the 2245H's reformed. Once I get those done I may take a stab at the 4345. But for now I will just stay with the 3 way 15" version.

    Any feedback or info is appreciated.

  2. #2
    Senior Member 1audiohack's Avatar
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    Interesting. I am trying to figure out how to not sound cynical, honest.

    So, the only thing JBL in this project is a driver (2123) that JBL never used in a home or monitor application. Granted it’s not a big leap from a 2121/2122.

    Add to that a knock down box likely not optimized for the woofer and some type of tweeter (I obviously didn’t look it up) without the normally used waveguide? Sorry but to me this resembles a 4344 like a Mustang resembles a Camaro.

    The journey can be very rewarding and or very frustrating. There is truly a multi dimensional skillset required along with a real tool list to help navigate through the fog if you want to build anything that approaches something like the 4344.

    I don’t know what your skillset is but if you don’t clone an existing design you might be in for a rough ride.

    I am all about DIY and I hope you have fun and it sounds great too, really but what you have proposed is far enough diverged from any JBL design as to render useless any helpful comparisons to your design.

    Anymore I just can’t imagine doing this without a measurement rig and DSP. Do you have a way to measure the response when they come together?

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

  3. #3
    Senior Member grumpy's Avatar
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    Looks like fun. Calling it a custom 3-way based around a 2123 mid might help in concept and execution.
    Hope your custom crossover included some 4434-like eq/contouring for the mid, which should make
    integrating the other drivers a bit simpler (woofer being mostly box driven, tweeter appearing to need
    a reasonable protective slope and perhaps some fore/aft optimization). Would be interesting to see how
    this comes out with a good measurement system and listening eval. Expect mid/tweet integration to be
    the trickiest. Enjoy the journey

  4. #4
    Senior Member Ian Mackenzie's Avatar
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    Ditto Barry and Grumpy

    Disclaimer on support:

    Without good driver measurement data (spl amplitude and impedance) from you we can only offer limited general non specific advice where a new member is not closely following a Jbl design.

    Unless you have already please invest in a reasonable measurement tool and mic. It will payback with huge time saving and a finished design that you are proud of. You will also learn and appreciate how the whole thing works.

    Unfortunately we do see new people come here seeking a customised design consultation over a few posts asking the same naive questions over and over and expecting someone to pull a rabbit out of a hat.

    Don’t get hooked on too much internet research. There is no point reading up on a topic and regurgitating it without doing anything.

    Yes it happens again and again

    The reality is s customised design is one of a kind and the ball is in your court to make it work.

    Having said the above good luck with your project.

    Quite a few have used the Beyma device and there are numerous projects on diyaudio.com

    There are some good Ebooks on loudspeaker measurement.

    I recommend you do your own measurements first and establish your own project goals.

    The 2123 is nice driver.

    An Active crossover with adjustment is a good way to start for the diy person

    I would definitely Biamp the woofer and the 2123 or if you can only passive use the Jbl 4344mk11 schematic as a starting point.

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    Quote Originally Posted by Ian Mackenzie View Post
    Ditto Barry and Grumpy

    Disclaimer on support:

    Without good driver measurement data (spl amplitude and impedance) from you we can only offer limited general non specific advice where a new member is not closely following a Jbl design.

    Unless you have already please invest in a reasonable measurement tool and mic. It will payback with huge time saving and a finished design that you are proud of. You will also learn and appreciate how the whole thing works.

    Unfortunately we do see new people come here seeking a customised design consultation over a few posts asking the same naive questions over and over and expecting someone to pull a rabbit out of a hat.

    Don’t get hooked on too much internet research. There is no point reading up on a topic and regurgitating it without doing anything.

    Yes it happens again and again

    The reality is s customised design is one of a kind and the ball is in your court to make it work.

    Having said the above good luck with your project.

    Quite a few have used the Beyma device and there are numerous projects on diyaudio.com

    There are some good Ebooks on loudspeaker measurement.

    I recommend you do your own measurements first and establish your own project goals.

    The 2123 is nice driver.

    An Active crossover with adjustment is a good way to start for the diy person

    I would definitely Biamp the woofer and the 2123 or if you can only passive use the Jbl 4344mk11 schematic as a starting point.


    Well, I just wanted some feedback on IF anyone has used these drivers together in any DIY project and NOT free consultation on a custom design. I do have some measuring software and tools. I will just wait for my Beymas to come in and get started on my project. Thanks Everyone for the info and feedback.

  6. #6
    Senior Member Ian Mackenzie's Avatar
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    Well that’s not what you specifically asked or stated.

    Your post was a sprawling story of your options.

    Why would you start off with a mix of drivers if you were planning on a 4345? Makes no sense.

    This is a JBL forum. That’s it.

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    Quote Originally Posted by Ian Mackenzie View Post
    Well that’s not what you specifically asked or stated.

    Your post was a sprawling story of your options.

    Why would you start off with a mix of drivers if you were planning on a 4345? Makes no sense.

    This is a JBL forum. That’s it.


    It's a Lansing Product DIY Forum!

  8. #8
    Senior Member pos's Avatar
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    Hello Drummerboy2, and welcome on board

    2245H+2123+TPL-150 looks like a nice combo with lots of potential (and of course lots of pitfalls as already pointed out).

    Not sure about the MCM woofer tho...
    The 2245H is a very good and versatile (sub)woofer, and you can replicate the 4345 tuning (280L @29Hz IIRC).

    If you go the 2245H+2123H route, you should be able to find plenty of info on active solutions for the ~300Hz crossover.
    This is a tricky frequency range to measure, so you better rely on proven solutions there.
    One advice regarding that range: keep the woofer and mid woofer on the same baffle to avoid having two different baffle steps in effect around the crossover frequency.
    Also try to get the 2245H off the floor to avoid triggering vertical modes in the >100hz range (dust cap at around 1/4 of the ceiling hight is often a good solution).

    The 2123H/TPL transition will be unknown territory (around here at least, maybe some have done that on the diyaudio forum), but at ~1200Hz this crossover will be much easier to measure and dial, and with a bit of patience and knowledge you should be a able to get a theoretically perfect acoustical crossover using only in house measurements.
    You might need to use the horn on the TPL to get it down to 1200Hz and -more importantly- match directivity with the 2123H.

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    Quote Originally Posted by pos View Post
    Hello Drummerboy2, and welcome on board

    2245H+2123+TPL-150 looks like a nice combo with lots of potential (and of course lots of pitfalls as already pointed out).

    Not sure about the MCM woofer tho...
    The 2245H is a very good and versatile (sub)woofer, and you can replicate the 4345 tuning (280L @29Hz IIRC).

    If you go the 2245H+2123H route, you should be able to find plenty of info on active solutions for the ~300Hz crossover.
    This is a tricky frequency range to measure, so you better rely on proven solutions there.
    One advice regarding that range: keep the woofer and mid woofer on the same baffle to avoid having two different baffle steps in effect around the crossover frequency.
    Also try to get the 2245H off the floor to avoid triggering vertical modes in the >100hz range (dust cap at around 1/4 of the ceiling hight is often a good solution).

    The 2123H/TPL transition will be unknown territory (around here at least, maybe some have done that on the diyaudio forum), but at ~1200Hz this crossover will be much easier to measure and dial, and with a bit of patience and knowledge you should be a able to get a theoretically perfect acoustical crossover using only in house measurements.
    You might need to use the horn on the TPL to get it down to 1200Hz and -more importantly- match directivity with the 2123H.
    Hi pos, Thank You for the Welcome to the forum. Actually I have been around the forum for a while but with other projects that didn't work out so well.

    After some thought, I will have the 2245H's repaired either by myself or someone else.

    It's funny you mention the 300hz range for the 2245H and the 2123H, that exactly the xover point I got with the 55-2963's and the 2123H's in Xover Pro. The TPL-150 seems to look better with a xover point at 1500hz, there is a dip around the 1200hz. The specs say it can xover at 1000hz. I know I will have to play with them to get it right.

    The TPL-150 can go down to 1000hz without the horn and down 700hz with the horn but I will loose horizontal dispersion. 120 degrees without horn vs 80 degrees with horn.

    Thank You for the tips.

  10. #10
    Senior Member pos's Avatar
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    80° is probably not too far from what you will get from the 2123 around 1.5kHz, so the horn will actually help in getting a good directivity match and a coherent power response.
    That 80° nominal figure is most probably only reached above 2kHz anyway, given the size of the horn.
    Chances are that the directivity will be quite well matched between 1kHz and 2kHz between the 2123 and TPL+horn, both rapidly gaining direcitivity in that range.

  11. #11
    Senior Member Ian Mackenzie's Avatar
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    Below is a very good “working” design that will guide you on using your Beyma device.

    As l mentioned earlier the real exposure on the Beyma is not here it’s else where.

    http://www.audiodesignguide.com/HiEff/HiEff2.html

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    Quote Originally Posted by pos View Post
    80° is probably not too far from what you will get from the 2123 around 1.5kHz, so the horn will actually help in getting a good directivity match and a coherent power response.
    That 80° nominal figure is most probably only reached above 2kHz anyway, given the size of the horn.
    Chances are that the directivity will be quite well matched between 1kHz and 2kHz between the 2123 and TPL+horn, both rapidly gaining direcitivity in that range.
    pos, Thank You. I will give it a try.

  13. #13
    Senior Member 1audiohack's Avatar
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    Quote Originally Posted by Drummerboy2 View Post
    It's a Lansing Product DIY Forum!
    Zactly.

    We do like to help and we obviously support DIY. The non Lansing drivers chosen for you project just limit our ability to easily do so.

    All the best,
    Barry.
    Last edited by 1audiohack; 01-31-2018 at 02:50 PM. Reason: I don’t use spell check. :)
    If we knew what the hell we were doing, we wouldn't call it research would we.

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    Quote Originally Posted by Ian Mackenzie View Post
    Below is a very good “working” design that will guide you on using your Beyma device.

    As l mentioned earlier the real exposure on the Beyma is not here it’s else where.

    http://www.audiodesignguide.com/HiEff/HiEff2.html

    Ian, Thank You. I saw this a while back and actually was going to do it. I saved it just in case I change directions. The Onken cab may be too big for my room that the speaker will be going in to. It's a nice Project if I had the room.

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    Quote Originally Posted by 1audiohack View Post
    Zactly.

    We do like to help and we onviously support DIY. The non Lansing drivers chosen for you project just limit our ability to easily do so.

    All the best,
    Barry.
    1audiohack, I totally understand. I do have a JBL woofer 2245H's that needs to be repaired but for the cab the size of the 4345 will be too big for the room I wanted to put it in. The 73" tv takes up too much room. I will try to figure out how to make it fit. I will just have to shuffle things around if it comes down to it. Even the 4344 MKII may be too big so that's why I wanted to try the knock down cab. I did find some 2235H's if the 55-2963 don't work out.

    The Link Ian put up is a nice project too but again too big for the room at this time.

    I will start the project and see how it goes. If it doesn't work out then I will just have to do the proper size cabs with the 2245H's or 2235H's.

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