JBL 2441 vs. JBL 2482

[Dr.db]

Hi,


I`m wondering if there are significant differences between these drivers in the midranges?
Let`s say between 500-5000hz

How do they differ in sound regarding to the mídfrequencys...!?


Is there a use of the highfrequency-ability of the 2441 when running it with a 2405 tweeter ?

Thanks a lot,
Olaf

[speakerdave]

I don't know. I haven't tried either one, but I also have considered the same question. Some people say they like the sound of phenolic diaphragms. I'm not aware of any published testing showing distortion figures that would reveal at what frequencies the 4" phenolic diaphragms reach mass break up, but I do know that the common metals (aluminum and titanium) are not exhibiting pistonic behavior most of the time, and I believe that adds a certain quality to the sound that is easy to dislike. There are two answers to that: one is beryllium; the other is an aquaplas coating on one of the the other metals. I have tried the latter in JBL 2450's and thought it worked very well.

The big disadvantages of phenolic are that except for the 1" JBL drivers using the phenollic 2470 diaphragm, it requires a special driver, and the diaphragms are not being made for the large format Altec and JBL drivers that used them.

The ability to reproduce high frequencies implies the ability to reproduce fast transients in the lower ranges covered by the driver. For me the question of using a slower-responding driver in the midrange and adding a tweeter entailed the effectiveness of the pscychoacoustic reading of high frequencies in a tweeter as a surrogate for the fastest possible transient reproduction in the midrange. I believe there is something to this, but my present take on this question is there is still blurring there that veils detail and that you need the fastest-responding driver practicable in all frequency ranges.

So for me the only remaining possible advantage of the large format phenolics is that if you have the right horns you can use a crossover at about 300 Hz and run an uninterrupted midrange up to 3000 or 3500. That is an ideal proposed by one theorist/experimenter. But for me, for the time being, I'm finding a two-way with top quality components is quite satisfactory, even with a supposed non-ideal crossover frequency of 700 Hz.

[pos]

Hi,


I`m wondering if there are significant differences between these drivers in the midranges?
Let`s say between 500-5000hz

How do they differ in sound regarding to the mídfrequencys...!?


Is there a use of the highfrequency-ability of the 2441 when running it with a 2405 tweeter ?

Thanks a lot,
Olaf

a 2405H will not do very well at 5khz.
You would need a 2403 or 2404 for that

[herki the cat]

Hi, I`am wondering if there are significant differences between 2441 & 2482 these drivers in the midranges say between 500-5000hz in the mídfrequencys...& the 2441 when running it with a 2405 tweeter ? Olaf

herki:
Well Doc; The spectrum below 100 Hz is a separate issue not addressed here except to say that High Quality Sound demands excellent phase-shift linearity & very low-level of phase distortion all the way from the lowest system frequency.... & for excellent transient response in full range monitors.... certainly up to 20,000 Hz. From 100 Hz up, percieved sound quality depends on what value you place on the "heart of the bass" occuring in the critical mid-bass spectrum of 100 hz to 600 Hz which requires excellent horn loading at least one & one half octave bellow the mid bass bottom cross over frequency of tipically 500 Hz or some where between 250 to 400 Hz of the RCA Photophone Theater Systems which always used Phenolic Diaphragms with excellent quality & durability up to 8,000 Hz in RCA's compression drivers noted for excellent horn-honk-free, cross over damping.

During the Alnico Motor period, JBL used in theater applications, the WECO 594-A driver design in their premium 20,000 guass, 2440 driver with aluminum diaphragms which offered excellent performance out to 9,500 Hz. This 2440 driver is considered by a few Golden Ear experts, to excell the 2441 all the way to 9,500 Hz. There is a camp that definitly prefers the 2441 because it has excellent percieved response above the 7,000 Hz break up point up to 12,000 Hz without support from a 2405. However, the extention above the 2440's 9,500 Hz roll off, is provided by the 2441 diaphragm edge susspension oscillations that do not really follow the actual electrical signal in this spectrum, but it seems to have a nice tinkle.

JBL 2470, with a gorgeous phenolic diaphragm has the same identical motor frame of the 2420. Note that 2420 is no slouch from 300 hz to well beyond 12 Khz, and it comes with a gorgeous tangential surround aluminum diaphragm intercangable mechanically with the 2470 phenolic diaphragm. 2470 presents excellent damping through out its entire frequency spectrum of 300 hz well beyond 10,000 Hz, and it presents excellent cross over damping at 500 Hz.

2470 sound certainly is not a "mashed potato sanwitch" sound, in fact it is a very smooth accurate sound with excellent Phase shift & low phase distortion. In the worst case, with 2470 being free of the subtile, lovable "tinkle" artifacts of the metal diaphragm above 7,000 Hz break point, you may only need to slightly readjust the mid bass spectrum level down a tiny bit to restore the system balance with the 2470. There Nothing wrong with adding a 2405 above 10,000 Hz if you like.

In a JBL horn, the 2428 Phenolic Driver is a Killer from 300 Hz up to 6,000 Hz, designed to yield very high Sound Pressue Levels power for Speech Reinforcement. I have been told the spacing between diaphragm & phase plug is rather wide to accommodate large diaphragm amplitude excursion. This large gap functions well up to 6,000 Hz but it performs as a a shunt acoustical capacitor with a steep roll off @ 6 Khz which may have some phase shift artifacts. :dont-know ....Consider the trade offs.

herki

[pocketchange]

I've been playing with my (EV) KD2's.
Currently: 2482's with Radian Dia's using Edgar design
2" Trachorn. 2404 for the top and CW1526 (Eminence) bottom w/ALK Universals XO's. Very tasty.

I would like to (also) hear Aquaplas coated Radians,
where do I sign up?

[jerry_rig]

herki:
2470 sound certainly is not a "mashed potato sanwitch" sound, in fact it is a very smooth accurate sound with excellent Phase shift & low phase distortion. In the worst case, with 2470 being free of the subtile, lovable "tinkle" artifacts of the metal diaphragm above 7,000 Hz break point, you may only need to slightly readjust the mid bass spectrum level down a tiny bit to restore the system balance with the 2470.
herki

Not to pick a fight, but I owned a pair of 2470s years ago. Although They were intended for sound reinforcement, I decided to use them as part of a DIY hi-fi. They certainly have a sound of their own. But to my ear, they badly lacked detail and depth. My guess is that the 2482 would be similar in that regard. Great for concerts, not so great for the home. However, you might love them.

[herki the cat]

Not to pick a fight, but I owned a pair of 2470s years ago. Although They were intended for sound reinforcement, I decided to use them as part of a DIY hi-fi. They certainly have a sound of their own. But to my ear, they badly lacked detail and depth. My guess is that the 2482 would be similar in that regard. Great for concerts, not so great for the home. However, you might love them.

Herki's two cents:
Mmm, jerry_rig, I what all equipment you had on the 2470 driver, which BTW, is identical to the time-honored Western Electric 713-A driver. The correct horn is very critical in these systems and the capacitors in the cross over network also are critical for dialectric dissapation. Western Electric capacitors sound like a straight wire. A single ended Western Electric 300-B __ 91-A type amplfier also sounds like a straight wire and reveals incredible quality from these speakers.

JBL 2470, and the Western Electric 713-A driver, have the same beautiful sound out beyond 10,000 Hz using the Western Electric type 32-A Horn with absolutely zero Horn Honk, especially with voice & speach. You can not fool speach, you've heard it all your life, and the clues are unmistakable. The RCA bench mark requires the loud speaker to sound like the speaking person is standing three feet to your side. An other RCA test is to jingle a key ring of 3 or 4 keys in front of an RCA Broadcast 44BX Ribbon Microphone and listen to the speaker strrugle with that order of transient response.

If you wish to see the nuts & bolts signature of a speaker __ A good Tone Burst Generator will reveal the typical speaker cone "over hang ringing" left after the test signal stops at the zero axis cross over point.

With either driver the sound is sweet & simply stunning. The Western Electric two way system has a 15 Inch Jensen Woofer and commands some $15,000.

[jerry_rig]

Mmm, jerry_rig, I what all equipment you had on the 2470 driver, which BTW, is identical to the time-honored Western Electric 713-A driver. The correct horn is very critical in these systems and the capacitors in the cross over network also are critical for dialectric dissapation. Western Electric capacitors sound like a straight wire. A single ended Western Electric 300-B __ 91-A type amplfier also sounds like a straight wire and reveals incredible quality from these speakers.

I tried the 2470s in several configurations. They were first used on a pair of 2345 radial horns and were bi-amped using a 700Hz electronic crossover and a Marantz 1060 integrated amp on top. I used LE15As with passive radiators in a sealed cabinet for the bottom, driven by a Crown D-150. I later mated them to a set of 2307/2308 horns and lenses with a passive JBL crossover -- most likely an LX-5. At that point they were driven by a Harmon Kardon Citation 11 pre-amp the D-150 power amp. All of this happened between 1974 and 1976. And although not up to today's high-end components, I believe these were pretty good for their time.

Given my experience, there is just no way my 2470s would pass the jangling key test. They absolutely cried out for a super tweeter. And I doubt they would mate well to one.

This is not to denigrate the 2470 (it is a great PA driver) or the Western Electric model. I assume the latter are highly sought after. Just my two cents. Peace.