i will make better pics soon...
here you can see some holes in the Mylar
i will make better pics soon...
here you can see some holes in the Mylar
I called Radian about the perforated surround, and after putting me on hold for a moment to consult with the owner/designer of the 1225 diaphragm, this is what I was told:
The two reasons for the holes are:
1: to increase the compliance of the rather stiff mylar surround.
2: To relieve pressure under the surround on ferrofluid in applications where ferrofuid is used in the gap.
BTW- He was the same gentleman you have been in contact with at Radian.
Hi,
> FWIW; I find the original combo surprising smooth sounding ( once some passive EQ has been applied to flatten out it's midband response ) .Originally Posted by Rudy
> I like the original combination quite a lot . They reach up to 12K quite handily .
> I can understand why they were used in the early 4425s.
> The combo sounds much nicer ( than it actually measures ) .
> Too bad JBL dumped this type of phase plug ( it's very coherent sounding IMO ) // in favour of their standard type annular type.
> I was going to toss out a pair mid-summer ( because I thought they were absolute junk that I got cheap ) .
> Then I re-aligned the diaphragms & then conjured up some passive EQ for the driver/horn combo and listened to them on & off for a morning .
> I was very impressed with the resulting character of this driver ( mated to a small Selenium HM17-25 horn ) .
> Not what one usually expects from a JBL Titanium diaphragm working on a magnetic assembly of this size .
> In a nut-shell ; Great Sounding Pink Noise ! .
> Very well behaved transient character across it's entire pass-band // ie; no discernable, ragged, FR areas that sound like they were about to reach "escape velocity" & then hurt someone upon re-entry.
> Needless to say , they're now back into the project queue ( ie; a front-fill, micro-box ) .
I recall that you used to have a modded pair of 4435s. This thread is of interest to me because I have a set of 4425s sitting around holding up my projector. I originally got them to as surround back speakers but one of them needs a new diaphragm, so I'm making due with a 5.1 system right now.
@ Guido
...Oh,Goodness! ...now i Know who you are Pass DIY Amps, BLS Horn , Everest Clone...da gibt es nicht viele, die eine Everest 2 in solcher Qualität nachbauen...so klein ist die Welt!
und was machen Sie denn jetzt mit den 4435 ?
with the Radians i'm not 100% satisfied, probably i will send them back and return to my original D8R2416 perhaps with aquaplas
Gut ,das ich die dann doch nicht bei Ihnen geordert habe ... irgendwie zischeln die Höhen leicht , nicht ganz so klares "klingeln" in den hohen Lagen.
Or you could keep the diaphragms and swap the driver for an alnico, or at least one with radial phase plug.
Good read guys, now I`m a little confused. How many versions of the 4425 are there and how do you know which is which? As a new owner of a pair, I`d like to know.
Incidentaly, where would the serial numbers be? I cant find any.
Not owning a pair, I can't swear to the Serial number location on 4425, but in other JBLs I own and most JBL's I've seen, it is usually an impression stamping into the metal (or plastic) nameplate (aka foilcal) either on the front baffle or the back near the input connections.
Regarding variants, the only thing I am aware of is the early ones seem to be more likely to have the driver with round holes through the phase plug, while later ones have the (better) phase plug with concentric slits.
See: http://www.jblpro.com/pub/recording/4425.pdf for the Data sheet,
and: http://www.jblproservice.com/pdf/Stu...ies/4425LR.pdf for the exploded diagram. This is the only data specifically about this model I could find on the JBL Pro sites.
If your drivers or crossover part numbers are any different, please post your info on this thread. Include pics with your serial number. Also, help everyone out by going to the "Serial number registry" thread (elsewhere on this forum) and post your data there.
This is my situation: one of my horns are not working on a newly acquired pair of 4425`s. My search for a replacement diaphragm came up with these three options.
1- OEM D8R2416 @ $300
2- Radian 1225-8 @ 125
3- Aftermarket @ 50
I decided (for the time being) to order two aftermarket units in the interest of getting these speakers up and running asap as they are far too nice to be on static display and that I cannot bare to be without tunes.
So for $100, I`ll be back in business shortly. BTW, this was before I knew of the Radian option.
I chose not to go with OEM because of price and the fear of a major sonic imbalance between a fresh horn and one that can possibly be 20+ years old. It would seem reasonable to assume an old diaphragm would be much more compliant and respond differently than a new one.
Now, in the event I`m not entirely satisfied with the aftermarket units, what are the differences between OEM and Radian units? One can never go wrong with OEM but are the Radians considered to be inferior,equal or superior to OEM?
I would appreciate some guidance!
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