I posit that JBL will migrate back to aluminum now that they have new surround technology worked out.
The difference in sonic character between LE85 (aluminum) and 2425/6 (titanium) is readily apparent to me. Aluminum is better (smoother, less harsh).
I don't hear any similar difference between Al and Be (2431 vs 2435).
I never did when I was using good old 2441s... sure those diaphragms at around $500 a pair aren't free, but I felt with luck I would be OK... never had a problem.Originally Posted by Roddyama
Since moving to beryllium diaphragmed drivers I have always used a series cap. At around $800ea. for the 4001 diaphragm and $1400ea. for the 4003s I am simply not prepared to be out there without a safety net. I have done some demos with the caps in and out of the circuit and so far no one has been able to hear a difference. I use a 47uF polypropylene film cap on them.
I am a huge advocate of aluminum diaphragms. I do think if cost is no object however the beryllium will give you a slight amount of detail that is masked with the aluminum. As one forum member said to me, "With the beryllium you can hear the rosin on the bow." It is true... it is damned expensive, but there is just that much more music revealed... goose bump material.
Widget
Just speculation here but...
It is possible that the ferro fluid in the 2435s also reduces the benefit of using the beryllium. JBL did forgo using ferro fluid in the 435Be hi-fi version.
Possibly in your temporary workshop listening setup it is difficult to discern the more subtle details...
Widget
I tend to think that ferrofluid in the gap of a compression driver actually smooths out and calms down the frequency response, when a metal type of dome is used...all titanium anyway. Titanium domes do take alot more abuse in live sound situations because of the tensile strength.The damped domes do sound smoother. At the expense of a little sensitivity, to my ears putting the brakes on the piston motion of the voice coil with ferrofluid cuts down on harmonic resonances bouncing around in the dome, making it somewhat less fatiguing to listen to. It would be interesting to me to hear a carbon/ceramic/silicon or even diamond type of lightweight high internal damping material that doesn't flex at all. These devices are so much more sensitive/efficient than other mid and woofer drivers, what's a few dB less from a slightly heavier material.
As Mr. Widget refers to...unobtanium may be on the drawing boards...?
Edgewound
I would like to try some dusted 275Nd dias at some stage, I think that would be very interesting. It also depends on the genre of music you play, brass come up particularly well on the titanium.
I am also inclined to think there are tonal differences in the ferrite and Alnico versions of the drivers. The outfit I bought both the 2420 and the 2405 said the Alnico were prefered for Hifi and they sell container loads to Japan.
I currently use alnico 2420's with the 2425 dias.
My Two Cents:
I posit that JBL will migrate back to aluminum now that they have new surround technology worked out.
The difference in sonic character between LE85 (aluminum) and 2425/6 (titanium) is readily apparent to me. Aluminum is better (smoother, less harsh).
I don't hear any similar difference between Al and Be (2431 vs 2435).
Gee, I hate to intrude__ but we would all appreciate it very much if JBL would produce again some original LE 85 / 2420 15 ohm Aluminum diaphragms with tangential suspension for replacements.
LE 85 OEM in the LC9-A Horn System, does present Stunning Sound Quality__totaly free of horn honk due to the extremely high level of LE 85's flux density. The 2420 big brother is also recommended. It has a heavier platform to support the diaphragm motion, & it is noticeable.
Enchanted by the prospects of the new JBL dimpled suspensions, I tried the 2425 in my LC9-A' s when it surfaced in the market place. I concluded it certainly will solve many problems, as intended, in high level sound
pressure applications where LE 85 & 2420 would not be welcome.
________________________________
Cheers, herki the cat
I missed this:
I believe that you were able to source a pair of the D8R275Nd diaphragms? They offer the best bang for the buck.The difference in sonic character between LE85 (aluminum) and 2425/6 (titanium) is readily apparent to me. Aluminum is better (smoother, less harsh).Well then, consider yourself lucky! You just saved yourself a ton of money!There is an order of magnitude difference in price!
While the Mg diaphragms are quite close to the Be diaphragms, the Al and Ti diaphragms are not. And virtually all of them benefit from the good old aquaplas.
"If it's metal, coat it."
Hello WidgetIt is possible that the ferro fluid in the 2435s also reduces the benefit of using the beryllium. JBL did forgo using ferro fluid in the 435Be hi-fi version.
Actually you need the Ferro in there it helps seal off the VC cavity. I would more concerned about the amount used as too much certainly does effect the Frequency Response. Too little and you have other issues. If they were used drivers with an unknown amount that certainly could be an issue. I know the ones I had were loaded with the wrong type of Ferro and had way too much in them.
Rob
http://www.audioheritage.org/vbullet...ad.php?t=14369
"I could be arguing in my spare time"
The messages you are quoting are 4 years old
LOLThe messages you are quoting are 4 years old
Thanks well at least it was a correction that set the record straight. You always have to watch these old threads seem to just pop up now and then.
Rob
"I could be arguing in my spare time"
True.
I think Zilch has moved on to 2452H-SL's as well as other brands in any case. I know he's also mentioned that he liked his stock LE85's which I can certainly understand. Then others have posted how the LE175's sound better than the LE85's and on and on it goes...
I hear a large difference in caps on the 2435. I have some top quality chateauroux MKP's that are considered to be all someone would ever need, but the 2435 only sound as sweet as my 2420 on russian paper-wax caps...
Yep.
Weird.
As an aside, as far as I'm concerned anyone posting about 2435's and their sound quality who purchased said 2435's off eBay have dubious samples at best and I consider their opinion highly questionable.
I don't give a rat's ass what the eBay ads stated, I've personally gone through a sufficient number of these second hand drivers and, quite frankly, I wouldn't own a pair if they were given to me. Why? Because I don't want to spend the roughly $1,600 it would take to get them back to spec. That would be a classic case of throwing good money after bad.
I just went through yet another pair a couple weeks ago and true to form they both had suffered surround creep and had virtually no ferrofluid. They'll still make noise and that might be good enough for some unwitting end users but they aren't a 2435 that would pass any kind of QC that I know of. They don't even rate as B stock.
Unfortunately a whole bunch of people bought into a product that requires a higher degree of maintenance than any of the older compression drivers and they now can't afford to bring them up to spec. They would have been better off taking their money and putting it towards some LE85's, 2420's, 2421's or 2425/2426's along with some new aluminum diaphragms and ending up with a more robust long term product.
And to think that people used to bitch and moan about the cost of the aluminum diaphragms...
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