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Thread: Pieceing together a JBL 4350 build in Australia

  1. #16
    Senior Member jbl4ever's Avatar
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    Hello Macsic, both the 4350 and 4355 are listed at 8 ohms due to the 2202 mid bass driver. Above that driver the impedance runs around 10 to 12 ohms. The 4350 crossover is set at 9 KHz and is a 3 pole 18/db and the 4355 is suppose to be at 10 KHz and a 3 pole also. The JBL factory never made a 2441 in 8 ohms but did on the 2450ís. If the C16R2441 kit is used in the 2450 you would be fine with the 3155 crossover.
    If you use the 3107 crossover used in the 4350ís you will have some comb filtering effect as the 2441 diaphragm will run up into the 2405 frequency range and over lap. Hope this helps

  2. #17
    Member macsic's Avatar
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    Quote Originally Posted by jbl4ever View Post
    Hello Macsic, both the 4350 and 4355 are listed at 8 ohms due to the 2202 mid bass driver. Above that driver the impedance runs around 10 to 12 ohms. The 4350 crossover is set at 9 KHz and is a 3 pole 18/db and the 4355 is suppose to be at 10 KHz and a 3 pole also. The JBL factory never made a 2441 in 8 ohms but did on the 2450’s. If the C16R2441 kit is used in the 2450 you would be fine with the 3155 crossover.
    If you use the 3107 crossover used in the 4350’s you will have some comb filtering effect as the 2441 diaphragm will run up into the 2405 frequency range and over lap. Hope this helps
    Hi,

    OK thanks for these notes. I understand my misinterpretation of the 4355 specs now. I had, several years ago, these 2440, 24441 drivers all in 16 ohms, the 2441 was my favorite for a long time with its aluminum dia but one day I got my hands on 2450 and 2451 with dia Titanium ribbed and aquaplas, I kept the 2450 for its compatibility with my horns but the dia aquaplas replaced all the others without regrets For having tried old crossovers I opted for a DSP over time, the good results are easier to obtain, but obviously all of this from the objective to be achieved. Sorry for the drift on the subject...
    Note: Google has translated my French.
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  3. #18
    Administrator Robh3606's Avatar
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    You are going to get comb filtering between the baffle set-up and physical offset from the horns. Look worse than it actually sounds in this case the measurements are misleading.

    Rob
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  4. #19
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    Quote Originally Posted by Robh3606 View Post
    You are going to get comb filtering between the baffle set-up and physical offset from the horns. Look worse than it actually sounds in this case the measurements are misleading.

    Rob
    I don't quite understand? Are you saying the comb filtering is inherent to the 4355 design, or will be caused by mounting the drivers in a vertical line above the 2202 with the cabinets rotated 90 degrees?

  5. #20
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    Would using the Selenium HL14-50N horn instead of the 2311 be considered an improvement? If I were to use it would it require any crossover changes?

  6. #21
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    All multi way speakers interfere with each other to some degree at and near the crossover frequencies, it's simply the natural result of the same sound being produced by two sources in two different places in space and/or time. Its actually better to make this interference occur in space vertically rather than horizontally as our ears are arranged on the horizontal plane and much more sensitive to comb filters on that plane. Flipping the speakers 90 degrees and arranging the mid and high / super high components is an improvement.

    The horn change is unlikely to be a change for better or worse, there just isn't enough horn there to make a noticeable difference. The only way to know if crossover changes are needed anytime you make changes to a speaker design is to measure the finished design.

  7. #22
    Administrator Robh3606's Avatar
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    Quote Originally Posted by kelossus View Post
    I don't quite understand? Are you saying the comb filtering is inherent to the 4355 design, or will be caused by mounting the drivers in a vertical line above the 2202 with the cabinets rotated 90 degrees?
    Yes and in the Array 1400 as well just look at the on axis measurements. You have baffle separation a high crossover frequency and the acoustic centers are offset, it's kind of a worse case. What matters is what's going on in the listening window. As bad as the on axis measurement look they average out to a surprisingly flat response. First two are a 1400 Array on axis and averaged. The last is the 4315 which used no horn, better.

    Rob
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  8. #23
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    Quote Originally Posted by Robh3606 View Post
    Yes and in the Array 1400 as well just look at the on axis measurements. You have baffle separation a high crossover frequency and the acoustic centers are offset, it's kind of a worse case. What matters is what's going on in the listening window. As bad as the on axis measurement look they average out to a surprisingly flat response. First two are a 1400 Array on axis and averaged. The last is the 4315 which used no horn, better.

    Rob
    Will rotating the cabinet 90 degrees and vertically aligning the mid-bass/cd/tweeter make things worse, better or the same?

  9. #24
    Senior Member Ian Mackenzie's Avatar
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    Greg Timberís says to use the 2405 with a 3rd order electrical slope from 8000-10000 hertz. This will result in a 4th order acoustic slope. Depending on your HF driver and horn the high pass electrical slope can be 1st to 2nd order from 8000-10000 hertz. This will give a 3rd to 4th order acoustic slope.

    Built in your cross over filters should be some response shaping for the flattest on axis response of the horn.

  10. #25
    Administrator Robh3606's Avatar
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    Quote Originally Posted by kelossus View Post
    Will rotating the cabinet 90 degrees and vertically aligning the mid-bass/cd/tweeter make things worse, better or the same?
    It will be very similar you won't know for sure until you measure. You are only changing the arrangement of the drivers but the spacing will remain approximately the same. I wouldn't get hung up on it just go with the way you want to lay the drivers out. Just remember the minimum distance recommended for these speakers.

    Rob
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  11. #26
    Senior Member Ian Mackenzie's Avatar
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    You may get better image/separation with the horn and slot above the mid.
    This is diy so you can experiment.

    A 1200 Joseph Crowe horn would be interesting.
    Those horns are an improvement on the Tad Horn.

    https://josephcrowe.com/blogs/news/e...dial-wood-horn

    https://josephcrowe.com/collections/1200hz-horns

    https://josephcrowe.com/collections/...dial-wood-horn

  12. #27
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    Quote Originally Posted by Ian Mackenzie View Post
    You may get better image/separation with the horn and slot above the mid.
    This is diy so you can experiment.

    A 1200 Joseph Crowe horn would be interesting.
    Those horns are an improvement on the Tad Horn.

    https://josephcrowe.com/blogs/news/e...dial-wood-horn

    https://josephcrowe.com/collections/1200hz-horns

    https://josephcrowe.com/collections/...dial-wood-horn
    If I was handy and technically apt I would certainly explore something like this. Sadly I'm not so I will keep it all original trying not to reinvent the wheel.

    My biggest gripe with the 4350's is having to biamp them. I would love to run them passively omitting the need for an electronic crossover and multiple amplifiers.

  13. #28
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    Bi-amping is a significant part of achieving the high output levels that the 4350s were designed for. If you don't want or need that capacity why not clone a different, less ambitious speaker project?


    Quote Originally Posted by kelossus View Post
    If I was handy and technically apt I would certainly explore something like this. Sadly I'm not so I will keep it all original trying not to reinvent the wheel.

    My biggest gripe with the 4350's is having to biamp them. I would love to run them passively omitting the need for an electronic crossover and multiple amplifiers.

  14. #29
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    Quote Originally Posted by Riley Casey View Post
    Bi-amping is a significant part of achieving the high output levels that the 4350s were designed for. If you don't want or need that capacity why not clone a different, less ambitious speaker project?
    How? I am sure a modern 400 watt Krell could drive the 4350 to it's potential without the need to biamp.

  15. #30
    Senior Member Ian Mackenzie's Avatar
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    Itís a bit technical.

    In simple terms a passive crossover in this particular loudspeaker design would cause significant power losses in the crossover, loss of damping on the woofers and the mid cone. The motional impedance of the mid cone and woofer may interact causing sub optimal voltage drives in the crossover region. The effect is modulation of the voltage drive and muddle sound.

    Bi amping eliminates the problem and allows a significant improvement in dynamic range and clarity.

    If you were to attempt a passive crossover it would be expensive and disappointing compared to bi amping

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