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Thread: Mass Rings vs AquaPlas / Transients

  1. #1
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    Mass Rings vs AquaPlas / Transients

    Hi All

    This topic was hinted at recently in another thread so I thought I'd give it a bit of air-time .

    I've been using le14a woofers ( or le14h ) in original S99 boxes biamped to whatever horn/driver combo grabs my interest ( usually 288-8K on a round horn - but today its 2440/2450SL ). Crossover point is 900 Hz. These small boxes ( virtual volume @ 1.6 cu ft ) give that woofer as much help in the mid as it's ever going to get. The last octave of info in the le14s is really quite dead ( like dead as in a door nail ) . Comparing to a 2235 on the other channel, its' pretty apparent that the huge amount of aquaplas coating in the le14 ( maybe 50 grams ) has smoothered the transients in the mid area. To my ears , the 2235 is able to deliver more life-like mids than a le14a .

    As a result of this impression, I find it hard to believe that JBL used this exact cone assembly ( unaltered ) in the S9500 or M9500 series. My guess is the speaker would voice better with a 50/50 split between a mass ring and aquaplas treatment on the cone . (just my opnion)

    I've been pursuing assembling a budget version of a S9500 since late fall. That's how I got to this conclusion. But, I found all is not lost for my project. I found putting a le10 in a smaller box sitting over top of the horn has restored the midrange transients. This 10" runs in parrallel with the le14 . They are very complementary to each other. Sensitivities match nicely and one fills in the others response weaknesses. Like the S9500 , this is not a bonafide D'Appolito setup ( the woofers are just too far apart to expect true midrange combining ) Still, works well with no apparent comb filtering . It is a a DIY nightmare when it comes to aligning the coils of the two speaker types because of the two different basket depths. A modular approach is the only way to go for alignment.

    Anyone else have experiences of this nature ?

    regards<. Earl K

  2. #2
    Rex Mills
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    Earl
    I have had a similar thing happen swapping out a pair of L-100 woofers (model# ?) into a L-166. The Lansaplas, Auqaplas, woofer had a slightly muddy, less resolving lower-mid than the mass ringed 166 woofer. Can't say if what I heard was the signature of the coating, different interaction with the xover in the 166 cabinet or any of the many variables that would come into play. Maybe others will chime in with thier experiences.

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    Administrator Robh3606's Avatar
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    Interesting comments. My XPL-200 almosts use the 166 woofer. They came in 2 flavors one with the mass ring and one with the Lasaplas/white stuff on the backs of the cone. I use one of each so I have a coated cone on one side mass ring on the other. The XPL crossover is at 300hz. They sound the same to me so maybe the change is on the high end of the response. I sure would not want to take the LE-14a that high. Like you said one stiff heavy cone to move.

    Rob

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    Member John B's Avatar
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    OK, point out where my logic may be faulty but it seems to me that a speaker’s motor assembly doesn’t care when it’s pushing a certain amount of weight whether it’s a mass ring on mass spread out over the cone. The point of the cone attached to the voice coils will move the same. And the aquaplas is applied to stiffen the cone for more piston like action and reduced breakup. So an aquaplas coated woofer should sound better in the midrange than one with a mass ring. The “smothered transients” may actually be less distortion. Comparing the same woofer that is. A 2235 may sound better than a LE14 for reason unrelated to aquaplas.

    The LE14 is crossed over at 800 Hz in the L220 and 240ti, both outstanding speakers. And used much higher in L55s, 99s and 101s.

  5. #5
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    "OK, point out where my logic may be faulty but it seems to me that a speaker’s motor assembly doesn’t care when it’s pushing a certain amount of weight whether it’s a mass ring on mass spread out over the cone."

    The mass controlling ring shifts the center of mass of the cone closer to it's apex resulting in greater linearity and control.

    "A 2235 may sound better than a LE14 for reason unrelated to aquaplas."

    I don't think it does sound better. They each have their own unique sonic signature. I'm glad I don't have to choose one over the other. The bottom line is, one can't go wrong with any of these transducers unless they employ them improperly.



    For those who care about such things... the current LE14H-1 cone assembly with dust cap weighs in at ~ 125 grams. The current 2234H cone assembly with dust cap weighs in at ~ 105 grams and the 2235H weighs in at ~ 140 grams. The suspension of the 2235H is quite robust and is capable of easily handling the MCR whereas the LE14H-1 is "close to the limit" and the addition of an MCR would overtax it's suspension.

    "Comparing to a 2235 on the other channel, its' pretty apparent that the huge amount of aquaplas coating in the le14 ( maybe 50 grams ) has smoothered the transients in the mid area. To my ears , the 2235 is able to deliver more life-like mids than a le14a"

    Yeah, I can see where you could come to that conclusion. I came to the same conclusion way back when I was building 2-way LE14A/LE20/LX8 and 2-way LE10A/LE20/LX11 systems.

    The LE14H-1 has very smooth response extending up to ~ 2 kHz and then it tapers of quite nicely. The 2235H has very smooth response extending up to ~ 1 kHz and above that it gets a bit ragged. Response "peak" for the LE14H-1 occurs at ~ 600 Hz and for the 2235H at ~ 900 Hz.

  6. #6
    Tom Loizeaux
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    Though the mass rings and AquaPlas coatings both add mass (weight) to thir cones, I suspect the AquaPlas coating damps much of the harmonics and upper frequencies that the cone would otherwise produce. The mass rings probably allow more higher frequencies to transmit to the cones while add mass to the entire cone/coil mechanism. This is one reason why the 2234 (2231/2235 without the mass ring) is popular in applications where more mids and a quicker low end are needed.

    Tom

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    Interestingly the 10" transducers in the new SK2-1000 use a combination of a mass ring and aquaplas. I believe it is 10 grams of each. Neither by themselves (20 grams of aquaplas or 20 grams of mass ring) gave the desired performance...

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    Okay , I'll bite

    Hi Giskard

    That''s interesting info. Though without actually hearing a 251J ??, I don't know what JBL is trying to voice/match that driver up to . Does the 1500al/fe share this type of split weighting ?

    <> Earl K

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    Re: Okay , I'll bite

    Hi Earl

    The system was designed as the center channel for a pair of K2-S9800's. It goes behind a perf screen.

    I do not believe the 1500AL/1500FE/1500SUB use mass rings at all.

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    Hi

    It goes behind a perf screen.
    Oh yea, I forgot about perf screens . That'll surely change things .

    I do not believe the 1500AL/1500FE/1500SUB use mass rings at all.
    Hmm,, I have some ME150(s) that I've been auditioning for a few months - it wouldn't surprise me if they were also 100% aquaplas-weighted. I find them a real nice project woofer when used no higher than 800 hz . When setup in vertical pairs, they do benefit from pole-splitting in the low-pass network ( passive and/or active ). This helps begin to level things out after @ 400hz . ( Mr. G.Ts' passive networks are a very fine roadmap for the practical implementation of this type of approach for filtering . )

    <> Earl K
    Last edited by Earl K; 09-08-2004 at 11:26 AM.

  11. #11
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    Okay Now,

    It's a 7 year old thread , but what the heck ( I feel this is the appropriate place for my question )

    4313B,

    Could you please share your observations of the sonics of aquaplased 2235H woofs ( where you aquaplased their cones instead of employing the usual 35 gram mass ring ) ?

    If you were to do the experiment again, would you feel it's worth trying a mass adding approach using some of each type ?
    ie ; ( 1/2 mass-ring & 1/2 aquaplas )

    <> cheers Earl K

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    Hi Earl,

    If I had to do it over again I would compare the mass ring 2235H with the aquaplas 2235H above 290 Hz. The original motivation for doing the aquaplas instead of the mass ring was to see if there was any way to increase xMech. There isn't. The aquaplas does stiffen up the cone quite nicely though and should change the upper response negating its use in something like a stock L300 or 4430. I prefer the aquaplased version for subwoofer use or in a JBL 4-way.

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    Ahhh, Okay,

    Thanks !

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    It's all about how, how much, and what you're starting with. A mass ring will indeed affect highs differently/less. If you're using it purely as a subwoofer I think I'd prefer a heavier overall cone to push breakup higher in frequency. For trying to extend the bottom end when using a wider bandwidth, where you need non-piston behavior to extend the FR, the mass ring is likely a better solution.

    Different combinations thereof would suit different apps better. I used heavy coating on my 122As to make them more useful as sub drivers. I used woodglue and shellac-base primer. They now are high Qts (.7) low Fs monsters, only useful as subs.

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    The Le14 is the worst woofer I have owned. ..way over rated IMO.

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