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Thread: 2440 diaphragm options

  1. #1
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    2440 diaphragm options

    I am about to purchase a pair of 2440 drivers. Before buying them I would like to know my options for diaphragm replacement.

    On eBay there are noname aftermaket titanium diaphragms from 53$.

    PartsExpress sell Radian aluminium diaphragms for 119$. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-728.

    I cannot find JBL original diaphragms anywhere on the net. Can they actually be purchased?

    Any other options?

  2. #2
    Senior Member louped garouv's Avatar
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    orange county speakers in california offers both authentic JBL diaphragms and aftermarket ones -- in the aftermarket segment, there are both relatively inexpensive and expensive (but not JBL Be offering expensive) options....

    http://www.speakerrepair.com/mm5/mer...AII-Diaphragms

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    Quote Originally Posted by louped garouv View Post
    orange county speakers in california offers both authentic JBL diaphragms and aftermarket ones -- in the aftermarket segment, there are both relatively inexpensive and expensive (but not JBL Be offering expensive) options....

    http://www.speakerrepair.com/mm5/mer...AII-Diaphragms
    http://www.audioheritage.org/vbullet...=2440+diaphram. Which one sound best? 2440 or 2441? The 2440 design is from 1954 and the 2441 from 1979. The drivers will work with a pair of H-5039 with lenses.

    At Orange county:

    JBL original D16R2440 cost 244$. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms . Aluminium. That is more for one diaphragm than the drivers cost!

    JBL original D16R2441 cost 272$. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms. Aluminium with diamond edge.

    JBL original D16R2445 cost 214$. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms. Titanium with diamond edge. These will sound hard according to what I have read on this forum.

    JBL original D16R2450 cost 212$. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms. Titanium.

    JBL original D8R2450SL cost 230$, there is no 16 ohm version. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms. Titanium with aquaplas. Better than the D16R2440? But not more expensive? http://www.audioheritage.org/vbullet...?3450-2450-Dia. From this thread it is not totally clear that this diaphragm will fit the 2440 driver, but very probable.

    JBL original D16R2451SL cost 228$. http://www.speakerrepair.com/mm5/mer...JBL-Diaphragms. What is the difference compared to D8R2450SL?

    After market (no name) is 99$ for 2445J (titanium), http://www.speakerrepair.com/mm5/mer...ket-Diaphragms. These should fit Peavy 44XT, so Peavy could fit also? Not an option.

    129$ for Peavy 44XT, http://www.speakerrepair.com/mm5/mer...ry_Code=Peavey. According to http://www.peavey.com/media/pdf/manuals/80300451.pdf, these are titanium.

    138$ for Radian 1245-16, http://www.speakerrepair.com/mm5/mer...ian-Diaphragms. Aluminium alloy and mylar surround. 19$ more than Parts Express. When googling I found this thread: http://www.diyaudio.com/forums/multi...ng-radian.html. Will they go above 5 kHz? But http://www.ratsoundsales.com/pdf/1245_1225.pdf claims 20 kHz.

    Be4016 Truextent SSX Beryllium Diaphragm 16 ohm cost 599$! Aftermarket diaphragms more than twice as expensive than JBL. Are they twice as good?
    http://www.speakerrepair.com/mm5/mer...ent-Diaphragms. http://www.electrofusionproducts.com...mDiaphragm.pdf.

    I am leaning towards the Radians since they are aluminum and half the price compared to JBL. Aluminium should sound better than titanium, but will fatigue with time.

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    Senior Member richluvsound's Avatar
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    twice as good ?

    more10

    more than twice as good ! once you have heard Be everything else is like wearing a condom

    ImHO..... ! Anyway, if you can manage to use genuine JBL parts you will find a lot more support for your project . After all our site is dedicated to the preservation of all things with a Lansing heritage . Thats what we know best and why we are here . I hope my fellow members do not mind me speaking as 'we' on this point .

    Rich

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    This turns out to be a very interesting adventure. The only reason I was even thinking 2440 is because I have a pair of H-5039 with lenses, and I wanted to try the original drivers on them. I currently have 2445 driving them. I am so pleased with my setup I thought it could be only marginally improved.

    Apparently the 2445 (1980?) with titanium diaphragms are inferior to 2440 (1954) with aluminum . Will the 2445 be better than the 2440 with aluminum diaphragms?

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    Senior Member spkrman57's Avatar
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    2nd the motion on Be diaphrams

    I love mine and nothing else come close.

    At least within my financial reach!

    Regards, Ron
    JBL Pro for home use!

  7. #7
    Senior Member louped garouv's Avatar
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    Quote Originally Posted by more10 View Post
    This turns out to be a very interesting adventure.


    ......


    Apparently the 2445 (1980?) with titanium diaphragms are inferior to 2440 (1954) with aluminum . Will the 2445 be better than the 2440 with aluminum diaphragms?

    another first step you can try is to have the ti diaphragms 'coated' w/ aquaplas
    that will essentially make them "-SL" versions, from my understanding...

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    Quote Originally Posted by louped garouv View Post
    another first step you can try is to have the ti diaphragms 'coated' w/ aquaplas
    that will essentially make them "-SL" versions, from my understanding...
    I will try that for my 2445 diaphragms.

    Thanks for all advice!

  9. #9
    Senior Member richluvsound's Avatar
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    More10,


    why not just put the Be in the 2445's Hey Presto

    Rich

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    Now I have read the http://www.audioheritage.org/vbullet...ight=Truextent thread.

    Next year I will have Be diaphragms, and I really want 2446 drivers with the phase coherent phase plug as well.

  11. #11
    Senior Member pos's Avatar
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    Quote Originally Posted by more10 View Post
    I will try that for my 2445 diaphragms.

    Thanks for all advice!
    The SL diaphragmes do not have ribs. I don't know what you will get by aquaplassing a ribbed diaphragm, but JBL never did it. These are two very different ways of handling breakups: trying to push them higher in frequency (ribs) or trying to damp them (SL).
    With the SL you loose some efficiency (lower mass break point), whereas the ribs result in "a slight penalty in accuracy" ( ref )
    I don't really understand why the ribs would reduce accuracy compared to a bare dome tho...

  12. #12
    RIP 2010 scott fitlin's Avatar
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    Quote Originally Posted by more10 View Post
    This turns out to be a very interesting adventure. The only reason I was even thinking 2440 is because I have a pair of H-5039 with lenses, and I wanted to try the original drivers on them. I currently have 2445 driving them. I am so pleased with my setup I thought it could be only marginally improved.

    Apparently the 2445 (1980?) with titanium diaphragms are inferior to 2440 (1954) with aluminum . Will the 2445 be better than the 2440 with aluminum diaphragms?
    Well, when they introduced the Titanium diaphragms back then, 1980 or so, what they used to say to us in the sales pitch wasn't that they sounded better! They were using the fact that these new diaphragms were shatterproof. Then, after they got through yakking about their heavier duty reliability, they would talk up the fact that the Ti diaphragms went up higher than the aluminum. The titanium domes got a reputation for being a bit hard sounding pretty quickly, too. And since we weren't shattering frams, and we had tweeters, it really didn't matter that the titanium went up higher. Also, I use 2395 lens horns, and the horn itself, won't get up that high, either. So, you go for what YOU think sounds best to you.

    I, personally, still like the sound of aluminum domes, but these days IF you REALLY want to better the performance via the metal diaphragm, Beryllium IS the way to go. This metal has the goods, it goes up high, it resolves the micro details in recordings, and is SMOOOTH sounding. Price is the drawback, Be is expensive, but, you read the threads concerning drivers using Be diaphragms, you see how satisfied people are with them.

    On aftermarket parts, the ONLY one I would even consider is the Truextent Be diaphragms by Brush Wellman, available at a few places, most notably Orange County Speaker.

    The Radian diaphragms for JBL drivers I tried, and did not like, way less dynamic sounding than the JBL part, and I didn't find it to be as smooth, either. Although, others feel they are smoother, and do better the genuine JBL parts, well, to each their own. I have my own opinion.

    With your 2440 drivers, I recommend either the D16R2440, or D16R2441. Setup and use, and you will see what the fuss over these older drivers is all about. OR, in the event you prefer your newer JBL drivers, 2440 drivers WITH genuine JBL diaphragms will sell pretty easily on ebay, and you can always use the monies to fund another JBL adventure.
    scottyj

  13. #13
    RE: Member when? subwoof's Avatar
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    coated ribs

    The second generation of the driver used in the DMS-1 studio monitors used such a beast.

    The driver number is 2450SL-a

    I bought a few at the '97 tent sale but never took pics.

    It was also the driver used in the HLA systems.
    << too many to list anymore >>

  14. #14
    Senior Member pos's Avatar
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    Quote Originally Posted by subwoof View Post
    The second generation of the driver used in the DMS-1 studio monitors used such a beast.

    The driver number is 2450SL-a

    I bought a few at the '97 tent sale but never took pics.

    It was also the driver used in the HLA systems.
    Interesting! I stand corrected.
    So the first generation DMS-1 used a "normal" SL diaphragm and then they changed to a ribbed one in the second generation?
    How do you like the sound compared to other SL diaphragms?

  15. #15
    RE: Member when? subwoof's Avatar
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    splitting hairs

    It's nearly impossible to A-B this subtle change when the systems are only used a few times a season and then at events where it's a noisy/crowded/reverberant area so until I can set up a quiet space and find the time, hard to tell.

    I have noticed however that when using the coated dia's in close-up stage monitors the EQ is much more behaved and less fatiguing. This has to translate into lower overall distortion.

    According to JBL the ribbing was to address break-up modes at high SPL's and believe me I can NEVER get more than a few watts into these under any circumstance.

    Since JBL "upgraded" all the large dia's with ribs it made sense to coat them too for the projects that used the older, smooth domes. The 2450SL diaphram is also used in the 475 ( interior shielded magnet version of the 2450 ) for the original K stuff that was sold in japan so consumer has them available too.

    sub
    << too many to list anymore >>

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