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Thread: Differences in driver transient Response VS cone mass

  1. #1
    Administrator Robh3606's Avatar
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    Differences in driver transient Response VS cone mass

    When I was first listening to my Heil set-up using 121A Mr. Widget brought up the fact that they have quite a bit of mass because of the mass ring. He's right compared to the Le14 series the 121A is about 20 grams heavier.

    The most common comparison with respect to differences in moving mass is the 2234 and 2235 drivers. The 2235 is 35 grams heavier.

    I know there are many anecdotes about how the 2234 is a superior driver into the midrange. The question is has anyone done a comparison between the 2 where they were compared using EQ where they both measured the same??


    His statement got me thinking as to what we are actually hearing. Is it the differences in the frequency response without EQ?

    Is it the mass making one driver "faster"?

    Is it a combination of both?

    If so which is the biggest contributor?

    Rob
    "I could be arguing in my spare time"

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    Dang. Amateur speakerdave's Avatar
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    Should rising inductance be one of the factors being considered?
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Administrator Robh3606's Avatar
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    Should rising inductance be one of the factors being considered?
    Hello speakerdave

    In the case of a 2234 vs. 2235 it would remain the same. If you look at a 8 ohm driver vs. a 16 ohm LE doubles as does BL with no net change in moving mass. I don't see added mass from say a mass ring having any effect on driver inductance.

    Am I missing something?

    Rob
    "I could be arguing in my spare time"

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    Dang. Amateur speakerdave's Avatar
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    My physics teacher said even if we rememembered nothing else we should remember F=ma. If acceleration is the relevant value keeping it the same would require an increase in force equal to an increase in mass.

    But I know that when real knowledge gets to work and all the relevant factors and relationships are introduced some surprisingly big things get washed out in the math and my kind of simplistic analysis will have resulted in nothing but fraught nerves and the pouring of a glass of wine earlier in the day than it should happen.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Dang. Amateur speakerdave's Avatar
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    I'm puzzled by rising response in big woofers like the 2235 in frequency response graphs.

    Question: Do a sweep and pink noise produce the same graph?
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Administrator Robh3606's Avatar
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    In Bass Box Pro there is an option to add Piston Band Response that shows as a rising response if I remember correctly. I will check it out later. Maybe that's it?? I have never tried that will later as well.

    Rob
    "I could be arguing in my spare time"

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    " my kind of simplistic analysis will have resulted in nothing but fraught nerves and the pouring of a glass of wine earlier in the day than it should happen."



    Okay that made me really laugh

    I do agree that when inductance is kept the same and force is modified for a change in mass, then the net aural result ought to be about the same.





  8. #8
    Dang. Amateur speakerdave's Avatar
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    Perhaps the rising response of a woofer like the 2235h results from loss of control. The woofer design was optimized for subwoofing and four-way monitors. The motor strength, suspension and cabinet size/tuning are set to balance over the relevant frequency range. The jbl fr graphs are generated in 10 cu ft standard volume, twice the recommended enclosure. After air pressure damping is lost, the suspension at some point will give up, maybe begin to whip, then the cone becomes a transmission line, and all hell breaks loose in the cone action, much of it irrelevant if the woofer is used as recommended. But on the graph it just looks like response.

    My point is that when properly deployed the woofer will work better in the higher frequencies than it does in the standard volume, perhaps not quite as well as in the lower, but the motor strength is still enough to move the cone.

    The lower mass of the 2234 just adds that last soucon of refinement in the 4435.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Administrator Robh3606's Avatar
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    The lower mass of the 2234 just adds that last soucon of refinement in the 4435.
    Yeah that was a stroke of sheer brilliance as it enabled double the power handling where it really counts and adding and extra 3 db of sensitivity for the overall system!

    Rob
    "I could be arguing in my spare time"

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    Administrator Mr. Widget's Avatar
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    Anecdotally I can add that from my listening experiences, the LE14H-3 and 2235H do not sound as snappy as the 1500AL, 2234H, or that slammin' K or E145. (Actually I have only heard the K version, but I believe the E is very similar.)

    On an off topic but related note, your explorations with the ESS tweeters and this thread finally got to me. I have a pair of 1.4 cu ft. test boxes and a pair of 12" PHL drivers that are extremely punchy, dynamic, etc. I just ordered a pair of AMTs to play around with them.

    I also have these interesting units I've been wanting to play with... Orban 674A
    They are an 8 band parametric EQ with built in fully adjustable 2nd order electronic crossover. I think one of these, a pair of amps and the above speaker compliment should keep me entertained for weeks.


    Widget

  11. #11
    Administrator Robh3606's Avatar
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    Hello Widget


    On an off topic but related note, your explorations with the ESS tweeters and this thread finally got to me. I have a pair of 1.4 cu ft. test boxes and a pair of 12" PHL drivers that are extremely punchy, dynamic, etc. I just ordered a pair of AMTs to play around with them.
    Nice!! You are going to have some fun

    Anecdotally I can add that from my listening experiences, the LE14H-3 and 2235H do not sound as snappy as the 1500AL, 2234H, or that slammin' K or E145. (Actually I have only heard the K version, but I believe the E is very similar.)
    Yeah I have LE-14h-3 and E-145's in the same room and of course there is difference but that is a bit of an extreme as a comparison The differences are 140 g of moving mass Le-14 vs. 55 g in the E-145. Slamming E-145 is a good description!

    After I thought about it I got curious about was how significant is 20gs?? I really like my LE-14's!

    One of the reasons I framed the question around the 2234/2235 which is 35 g is many have heard both. I have never had the pleasure of listening to a 2234.

    Anyway I thought it could be a fun discussion.

    Rob
    "I could be arguing in my spare time"

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    Quote Originally Posted by Mr. Widget View Post
    Anecdotally I can add that from my listening experiences, the LE14H-3 and 2235H do not sound as snappy as the 1500AL, 2234H, or that slammin' K or E145.
    How would you compare the LE14H-3 and 2235H soundwize?
    Both have about the same motor force, but the LE14H-3 has about 20grams less coneweight...

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    Senior Member Ian Mackenzie's Avatar
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    Hi Rob,

    It would be a good question for the engineer who designed the system.

    The crossovers have different values for the capacitors of the woofer.

    But l think in the system the woofer would have a similar system response.

    That narrows down what you might hear.

    I personally think it’s the added mass of a solid object right on the voice coil. At the crossover point you are largely listening to the dust cap not the overall cone. The magnetic flux is the same but the efficiency is higher on the 2234 by a few dB as you would expect.

  14. #14
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    Regarding cone mass: The TS parameters tell 105 gr for the 2234H and 150 gr for the 2235H, resp. The mass rings are 35 gr. So, where are the missing 10 gr? Did JBL apply 10 gr of glue per speaker just for the rings?

    Best regards!

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