Best Aftermarket Diaphragm For 2404

[andychris]

Hello
It's my first message here. I do'nt speak a very good english, so excuse me.

I've got a pair of used 2404 and one of them is a little more powerfull than the other and when I had a look at the diaphragms, I had to see that they were not the same. It's maybie my probleme. So I would like to change those diaphragms but original JBL diaphragm are too expensive and I saw that a lot of shop are selling aftermaket diaphragm on ebay. BUT what to buy ? Is there a good thing to buy ? I can see that there are aluminium or titanium diaphragm, but what to buy ? Is there a real difference between the original ones and the aftermarket ones ? I use those 2404 as super tweeters on my S3100, so only hifi use.

thanx if you could help me
here is a picture of my diaphragms

[toddalin]

The diaphram on the left is a 2402/075 while that on the right is a 2404/2405/077. The 2402 has a larger radiating area and so would be expected to play a little louder.

Can you do me a huge favor and measure (as accurately as possible) the outside diameter of the inner brass ring of the 2404/2405 on the right?

I am thinking of "turning" inside diameter of the 2402/075 phase plug to accomodate this diaphram and there is an interference at the outter edge of this ring.

Thanks!

[andychris]

thanx for your answer, but do you know the differences between titanium/aluminium/aftermarket/genuine diaphragms ?

here are the dimensions

[SMKSoundPro]

but do you know the differences between titanium/aluminium/aftermarket/genuine diaphragms ?

Dear Andychris,

I, too, have asked these same questions and the answers are buried here in this forum.
What I have learned is:

Titanium is a "stronger" metal. Will take a pretty good pounding, but maybe not the best sounding.
Aluminum is very good sounding, but gets brittle and breaks over time and use.
Is it possible for JBL to use titanium diaphragms for the compression drivers for its stronger character for reliability and less failure at the expense of sound quality?

I have used a couple of different aftermarket 2405 diaphrams from the sellers on ebay and found: that when loaded into a 2402/075 bullet tweeter that they work, but are just not quite right. When you have the opportunity to hold each of the diaphragms in your hands and really look it over, you see the minute differences that you can really hear.

I have stopped using aftermarket diaphragms in all applications, period. They are just not the same as the JBL diaphragms. They may look the same, but I bet my bottom dollar that they are not. If they were the same, we would know it and tell the world which ebay seller has the "good" ones at a cheaper price. Alas, this is not the case.

If you want the same performance that the incredible JBL engineers want you to have, you will use the real JBL products.

I don't want this post to scold you to use the OEM parts, but that is really the way it works. ( At least in my small world here in Alaska.)

Welcome to the forum! There is so much information here. Try the search function above and search for "aftermarket diaphragms." You may find some actual data and performance graphs to prove my points.

Happy holidays to you and yours,

Scotty.

[Predrag Dukic]

"
Titanium is a "stronger" metal. Will take a pretty good pounding, but maybe not the best sounding.
Aluminum is very good sounding, but gets brittle and breaks over time and use.
Is it possible for JBL to use titanium diaphragms for the compression drivers for its stronger character for reliability and less failure at the expense of sound quality?
"

Exactly that: In Mechanical engineering it is known that duraluminum has a finite life; it breaks from fatigue, sooner or later. It is also more sensitive to corrosion than pure aluminum.

It is lighter than titanium, so equally stiff diaphragm (in plane direction - tangentially to the ring radiator cone or the c.driver dome ) is thicker than titanium.
Titanium, being thinner for the same weight per area, leads to flexural vibrations, and the last invented remedy to this problem are radial and cross-cross ribs on the titanium dias.
See the newest titanium drivers. They all have ribs. Ribs have the same function as waves in corrugated cardboard- increasing flexural stiffnes of a thin and floppy material.

[toddalin]

Thank you for the measurements.

As to the aluminum vs titanium, I guess that depends on who you ask and the chosen application. I can't imagine that I would ever "wear out" a set of aluminum diaphrams due to fatigue in my lifetime in my living room setting even 4 hours a day, everyday. I know titanium can be coated to sound smoother (maybe more like aluminum).

I've never heard truely similar units in an A/B setting so don't know if I hear a difference and which I would prefer.

[Mr. Widget]

.

[andychris]

thanx for all

as I can see I've got nothing to do but buying a new pair or real original diaphragms. But paying again more than 200$ is not a good bargain for just a supertweeter. I don't understand why aftermarket diaphragms always exist if they are so bad.

[Zilch]

Because, in some applications, it doesn't matter, as long as they make VHF sound....

[4313B]

Why do people feel the need to buy JBL transducers and then stick any old aftermarket diaphragms in them. Why not just buy cheap drivers in the first place and leave it at that?

With respect to the various diaphragm materials, "I doubt they'd be able to hear a difference between any of them." Given that, buy what you can afford and don't second guess yourself.

[Mr. Widget]

Because, in some applications, it doesn't matter, as long as they make VHF sound....

Yeah, like in the closet with the power turned off.


Merry Christmas Zilch!


Widget

[speakerdave]

Because, in some applications, it doesn't matter, as long as they make VHF sound....

Yeah, in fact the general theory of sound reinforcement the way it is practiced in far too many places, is the more distortion the better, since it sounds louder.

[Mannermusic]

thanx for all

as I can see I've got nothing to do but buying a new pair or real original diaphragms. But paying again more than 200$ is not a good bargain for just a supertweeter. I don't understand why aftermarket diaphragms always exist if they are so bad.

Greetings from Detroit,

I don't think anyone is saying the aftermarket diaphragms are "bad" necessarily, they just are not exactly the same. You may like them better or worse - depends on your application and whether you have "golden ears." I have gone both ways and been lucky with results. Orange County Speaker, CA, had some aftermarket diaphragms a few years ago that they "guaranteed" sounded as good as original JBL. I suspect they were "reverse engineered" Chinese jobs. Anyway, I bought a couple for my 2426H drivers and found them to be indistinguishable from the original JBL jobs - but maybe I'm not in the "golden ear" category! In any case, one test is worth 1000 expert opinions! So it becomes an experiment and you are the engineer in charge! Mike

PS: I use original JBL diaphragms in my 375 drivers (main system).

[Robh3606]

Aftermarkets are great!! If all you care about is the money saved. Here's a pair of aftermarkets and here's a pair of JBL's. Which would you want to use?? For SR work maybe for home no way.

Rob

[Predrag Dukic]

Got my first 2404h s on friday. Two 2404h-1 and one 2404h. Diaphragms look exactly like those, left is H-1 and right is H
Underside bears date of manufacture and marking 2402 on H-1 dia.

Now, looking at them, I am sure that 2402 dia is NOT duraluminum.
It is also so shiny, polished as yours, only with silver rings, not gold color.
Since the date of manufacture is in '85, and should be heavily corroded by now,
I believe it is some other alloy, maybe even pure aluminum.

It makes sense, because 2402 is supposed to go lower in frequency, so maybe dural is too brittle for it.
I can also see ballpen trace on the outer AND inner edge of the dia.
Now seeing it for the first time with my own eyes, I realize that this trace in fact forms a halve-roll surround/suspension for this dia. lowering the Cms of the dia.

For me that mistery is solved.

Diaphragm v-shape is identical for both dias, the difference is only in the additional space/surface because the outer ring has larger hole, and inner ring has smaller outer diameter.
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