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Thread: Horn/Driver Comparisons

  1. #16
    Steve Gonzales
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    Power tests

    Do you think the larger backcap will make the difference when some real world power tests are made?. (My) Not having much knowledge of these types of tests (the ones you've already run), is it your experience, that a driver can exhibit an ability to play below it's FS ( 900hz- 2435HPL) and still perform with good, usable output, in a real world installation, crossed over below it's recommended 1.1k?. In other words, are the people that own 2435HPL's to assume that it is okay to cross them over at 800hz?

  2. #17
    Administrator Mr. Widget's Avatar
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    Interesting questions... we should have run an impedance sweep on the 2435HPL and 435Be with both the large horn and one of Zilch's smaller horns.

    Zilch, if you bring driver #6 back over here we could run that test as well as run the distortion test.

    Widget

  3. #18
    RIP 2011 Zilch's Avatar
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    I'm compiling a new measurement list.

    I want to try 2431H and 2435HPL on H9800, as well, now.

    And 2431H on PT-F with our crossover for it.

    We also have a 2430H on the way for evaluation.

    Note to readers: We have a JBL UHF driver study on the docket here, too - 2402, 2403, 2404H, 2404H-1, and 2405....

  4. #19
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Guido
    I've a question regarding post #9:

    Does it mean that the 2431 is
    5 dB more sensitive than the 2426 and
    3 dB more sensitive thean the LE85 ?
    Yes, in this comparison. Thanks for pointing that out, I meant to address it but forgot. I believe the drivers are all inherantly very similar in their sensitivity, but for us to compare these three drivers on the PT-F1010, both of the 1" drivers required adapters. I believe these adapters are responsible for the lower output as well as the undulating response seen in the Blue and Green plots. I assume that due to the physical offset of the LE85 vs. the 2426, it's sensitivity was less affected.
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  5. #20
    Steve Gonzales
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    COOL

    Looking forward to the results!

  6. #21
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Zilch
    Post #4: We don't find a HF extension performance advantage with Be diaphragm (and $1000 premium cost) 2435HPL.
    True. I'd like to point out that one of Zilch's goals is to find a combo that will eliminate the need for a tweeter. I am not sure if any of these combos are a stand out in that regard.

    I would say that looking over these plots the most expensive drivers, the 435Be, and the 2435HPL have the most linear output through most of their range. This to me is significantly more important than extension, but all of these components are only parts of a system. It is up to us as designers to determine how best to use their capabilities.

    If I were going to pursue a project with any of these combos, I'd take these plots into consideration but I'd make my final determination based on a series of subjective listening evaluations.

    Widget

  7. #22
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    Quote Originally Posted by Mr. Widget
    True. I'd like to point out that one of Zilch's goals is to find a combo that will eliminate the need for a tweeter. I am not sure if any of these combos are a stand out in that regard.


    Widget
    Aha! I wondered if that was in the back of someone's mind.
    Out.

  8. #23
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    Quote Originally Posted by Zilch
    Note to readers: We have a JBL UHF driver study on the docket here, too - 2402, 2403, 2404H, 2404H-1, and 2405....
    I like to help on that one if it'd fill things out. I can bring an "H" structure, an unused 2405 dia, and an unused 2405H. I say unused even though they're new - they've been new in the box for 15-20 years...(does that affect these types of dias?).

    I could also bring an 035Ti and 035TiA for comparison purposes.

    John

  9. #24
    RIP 2011 Zilch's Avatar
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    What I suggested to Mr. Widget:

    "Let's hold off on the tweeter project until John can come help."



    [We had PLENTY on the plate with the mids/waveguides....]

  10. #25
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    Quote Originally Posted by Zilch
    "Let's hold off on the tweeter project until John can come help."
    Just give me a little notice if you can...

    John

  11. #26
    Administrator Mr. Widget's Avatar
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    One Last Plot ...(for now)

    Here is a comparison between the 2431 mounted on the PT-F1010 and the K2-S9800 mid driver and horn used full range. (435Be driver on the H9800 horn) The K2 combo was better on the lower end, as it should be since it was designed to operate down to 800Hz. It was also smoother all the way to 15KHz. To me the most impressive thing was the unit to unit consistency of these premium products. The Blue plot is from one 435Be on one H9800 and the Green plot is another 435Be on a separate H9800. They were identical in performance between 600Hz and 15KHz +/- 0.32 dB!!!

    Widget
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  12. #27
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Mr. Widget
    Before we began our horn comparisons we wanted to explore the low end capabilities of the 2431 and 2435HPL compression drivers with their small back cap and compare them to the 435Be with it's large back cap. To do this we mounted the three drivers on a 500Hz 1.5" throat horn I have that is about the size of an Altec 511. It is not a CD horn so it's on-axis response is reasonably flat without compensation.

    Here we see that the low end performance of the 435Be, 2435HPL, and 2431 are all quite good. It would seem that the larger back cap isn't necessary for performance below 1000Hz. We did not do any listening tests or power tests measuring distortion, but the initial measurements were surprisingly encouraging. I am not sure if it is due to the back cap or other tweaks, but the 435Be did exhibit, albeit by a small margin, the flattest overall response of the three.
    I reposted this post to bring us back to the topic of the low end performance of the 2431, 2435, and 435Be.

    Widget
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  13. #28
    Administrator Mr. Widget's Avatar
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    Here is a post of the 435Be back on the large horn. We drove the driver to a fairly loud sounding 95dB (we had our fingers in out ears as the stepped sine wave screeched) to measure the second and third harmonic distortion levels. The distortion levels were raised by 30dB. The second harmonic is at a fairly low level, and the third is 60dB down through the usable portion of the spectrum.
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  14. #29
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    Here is a plot of Zilch's "better" 2435HPL. We are not sure what the specs are for distortion, but this unit has significantly more third harmonic distortion that the 435Be.
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  15. #30
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    Here is a plot of the 2431. Again we aren't sure if this is within specs, but the distortion is significantly greater than the 435Be. Hopefully we can get them tested by JBL and then we can measure them again to see if these plots are indicative of their performance. When we measured this driver we heard a noticeable buzzing sound as the frequency swept through the lower frequencies.
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