It undjulates because of comb filtering between the two drivers. You should try using a steeper slope on the 2404. They have quite a bit of output all the way down to 4K or so.
Rob
It undjulates because of comb filtering between the two drivers. You should try using a steeper slope on the 2404. They have quite a bit of output all the way down to 4K or so.
Rob
"I could be arguing in my spare time"
"
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.
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.
[/QUOTE]
Do you know if there is a difference when you use some 2405 diaphragms on 2402 tweeter ? It's more and more difficult to get some 2402 diaphragm that most of 2402 tweeters are mounted with 2405 diqphragms
Thanx
It will not reach as low as the original diaphragm. Maybe it reaches higher. Someone shurely has made a measurement of this.
JBL made some 2402's with D16R2405 diaphragms and tagged them 2402-5.
In the "Ring Radiator Comparisons" thread near the end I posted pictures and measurements of a brand new one. Start at post 179.
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
As far as I know, putting a 2405 diaphragm into a 2402 is not possible. The phase plug can not clamp the diaphragm properly.
Allan.
No it is quite possible... see Barry's post above. JBL did do it and other people have done it as well.Originally Posted by Allanvh5150
Widget
Hello,
I own a pair of JBL L 65 B and a month ago the 077 tweeter stoped working.
I bought a aftermarket diaphragm for just US$ 30,00 and replace it.
It worth what I paid for. It sounds lower and does not have the cristal sound.
I decide to buy the original used tweeter that costs 10 times more because there are no more original diaphragm for sale.
Regards from Brazil.
Hello Jose!
Welcome to Lansing Heritage.
The genuine JBL replacement diaphragm is part number D16R2405. JBL currently has 131 in stock.
Do you have a local JBL supplier or repair shop?
All the best,
Barry.
If we knew what the hell we were doing, we wouldn't call it research would we.
Hello,
No I dont't have here in my country.
Where I can find the original ?
Thanks
Maybe these guys is willing to help: http://www.simplyspeakers.com/jbl-speaker-repair.html
Johnny Haugen Sørgård
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