The rubber part will just stick out of the cap a bit, but still maintain seal :
http://www.audioheritage.org/vbullet...l=1#post283226
The rubber part will just stick out of the cap a bit, but still maintain seal :
http://www.audioheritage.org/vbullet...l=1#post283226
Has anyone compared the 4" Be diaphragms between the 2240-2451 JBL models and if the sonic character changes through the driver models?
Herman
I might be mistaken about your post here. Do you mean the 2440-2451 JBLs?
This is obviously just my opinion!
I run my stuff for PA use. I have had 2440s, 2441s, 2445s, 2446s, and now I finally got a single 2450 to compare. I retired years back and left the field.
The phase plugs in the drivers changed over the years and there was definite differences (improvements) in the higher frequencies (like from 10 - 20k).
In the old days people used the bullets or slots, as we called them, to improve high freq on the 2440s. When I bought 2441s I ran them alone up top.
I now have 2 x 2445 and 2 x 2446 drivers right here and one of them sounds much better up high than the other 3 do? I had hoped to actually hear the difference in the phase plugs between the 2445 and 2446. I bought them used and can't verify the diaphragms other than sonically to my ears. I have the main EQ rolled up in the highs to compensate.
I don't have my old 2440/1 models anymore to compare with. Sold them off when I retired.
Can I ask what Be diaphragms are? I'm not familiar with the letters.
I haven't compared the 1 1/2" drivers against the 2". Years back I compared the JBL 1" 2425/6 to the 2" 2445/6. I felt the 1" sounded too harsh and the 2" had better much clarity in large rooms Bars and Auditoriums. It maybe preconceived by me but I still feel the 2" is best for large PAs. I am still reluctant to try the 1 1/2" drivers against the 2" versions for that reason.
Almost everyone's posts here seem to be about home use. Being retired I finally use my stuff in the house and yard and I stand firm in my beliefs. I may be too old here.
They are identical difference being throated vs. throatless. Drivers like the 2450 vs 2451 are a perfect example same phase plug the 2450 has the typical throat with a recessed screen. On the 2451 there is no throat extension and the screen is right there.I am still reluctant to try the 1 1/2" drivers against the 2" versions for that reason.
Be stands for Beryllium a very expensive diaphragm material used it TOTL systems.
http://www.lansingheritage.org/html/...p/pro-comp.htm
http://www.audioheritage.org/vbullet...hp?33568-476Mg
Rob
"I could be arguing in my spare time"
Thanks Rob.
So is the final exit throat diameter of the 2450 2" and the throat of the 2451 1 1/2" or do I have that wrong?
I'm interested if it adds harshness to higher output volumes coming out of a smaller exit.
I saw that they can use the same diaphragm and I didn't know that.
I recently got even more confused when I thought I saw a used set of 2450 drivers without the throat extension?
Then there's another version 2450sl? which I believe is 1 1/2 throat?
It will be fun to compare and see the sonic differences.
YesSo is the final exit throat diameter of the 2450 2" and the throat of the 2451 1 1/2" or do I have that wrong?
The 2" throats had a decades old flare rate. The new throatless design is actually supposed to reduce distortion. There is a Technote about itI'm interested if it adds harshness to higher output volumes coming out of a smaller exit.
http://www.cieri.net/Documenti/JBL/T...1,%20No.31.pdf
You are not alone I got confused as well, there are 2 versions.I recently got even more confused when I thought I saw a used set of 2450 drivers without the throat extension?
Then there's another version 2450sl? which I believe is 1 1/2 throat?
Rob
"I could be arguing in my spare time"
I did get a set of the new type bells for comparison. One thing for sure, it beats the heck out of lugging around the old huge aluminum models.
I have these for comparison as well.
BTW I was going to use those 1 1/2" horns for stage monitors. If they throw well and sound good, they'll be on FOH.
The 2450SL is similar to the 2451, different mounting bolt pattern, both 1 1/2" exit (no throat on either). I think it's sebackman tried both the 2450SL and 2451 w/Be phragms and preferred the 2451 by a slight bit.
I don't see anyplace selling the Truextent Be Diaphragms. Reconing speakers has them listed with call/email for price/availability. Used to get them for $500 ea, seems like I heard $800 ea recently?
https://reconingspeakers.com/product...m-16-ohm-copy/
for anyone interested in opinion!
The Selenium drivers on those EV bells sound very sweet to me. They aren't harsh and seem nicer close up in the house at high freq.
Outside I had the system turned up a bit, and to me, the 2" 2445 on their bells sounded like they cut thru better in the upper mids to highs, and still did not sound harsh in all freq. heard (used above 1200? if I remember the points?).
That's where I noticed that a few of the 2" drivers seemed to be rolling off early and I boosted the EQ at the top of the range. As I stated, I just don't know what diaphragms are in what because it was all bought used. One of them sounded much better up high and I wish I could ID that diaphragm.
I didn't mark the driver so I would have to set it all up again for a good listen. To be fair, I would also have to swap out stuff to eliminate any other variables in the system. I just found it interesting that 1 of 4 drivers sounded better up high.
I too should wait for others who have tested to chime in here. It's just my ears and I am getting old! Urrggg. sorry for the rambling...
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