I've been doing some research because I recently acquired a couple of JBL2440s that were supposed to have 2441 diaphragms (one does but with stress fractured surround, but the other has a 2445J diaphragm) so I am effectively looking to rediaphragm one or both, which got me considering my options.
The cheapest way to go would be to rediaphragm the one with a 2445J, and then they would match and have decent HF extension, in addition, although exactly how close to a 2441 I don't actually know since I have read that the phase plugs also differ between the 2440 and 2441 so comments on this matter are solicited. But, presumably, the HF would extend several Khz beyond 10Khz, say at least to 15Khz(?) which would be enough for my purposes here.
The other issue I am considering is aluminum vs titanium. I would really like to go aluminum for SQ reasons, but cost is a factor, considering that two new 2441J diaphragms price out at around $270 apiece. The other major alternative is to use the Radian 1245-16 diaphragm in both, but there apparently has been considerable dissension in other forums regarding the merits of lack thereof of this diaphragm as a JBL replacement, although to give the Radian its due, the worst criticism of it that I've seen still admits it as the best of the aftermarket replacements.
I felt that for this application that I could accept a tradeoff in ultimate ruggedness because I wasn't planning to beat this speaker to within an inch of its life, so the Radian was still in the running from that perspective. Also, the JBL 2441J aluminum diaphragm diamond surround is apparently a significant weak point in high stress applications, as witness the cracked surround on the one driver I received. But that leaves HF frequency response where there appears also to be a difference of opinion, and there I found some information that clarifies the matter significantly for me, at least.
Radian uses the 1245 diaphragm in one of its own drivers, the 950 and includes a response graph, albeit considerably smoothed. This is presumably an optimal application for this diaphragm, but it is reasonable to assume that a similar response is obtainable in the JBL 244x family for which this diaphragm is also intended. But, comparing this graph with the one that JBL provided that superimposes the 2440, 2441 and TAD4001 responses on a JBL 2350 horn, some things become clear.
Above 2khz to about 10khz, the Radian graph shows a smooth 10db rolloff, above which it flattens out (on the average), but with several db of ripple to 20khz. However, this includes an additional 6db dip at 14khz, so the worst case falloff is around 16db, relative to midband. This is still several db more output than the 2440 in the 10-20Khz octave, but limits system efficiency for flat response to the 97db/w/m range if a response out to 20khz without significant dips using a passive xover is required. Comparatively speaking, the JBL 2441J diaphragm has at least 8db more output in this octave, so will support a 2-way passively xovered system with efficiency up to about the 105db/w/m range out to 20khz. In all cases, a CD type horn is assumed. With a smooth flare horn, even the Radian might achieve perhaps 103-104db/w/m on axis while avoiding 'titanium sound' (My basement blasters use all original 2445J's so I know whereof I write here).
So, I am still undecided between the Radian aftermarket diaphragms and shelling out for original D16R-2441s. This particular system does have a smooth tractrix flare horn but will be over 100db/w/m efficient. Comments are appreciated. Btw, besides Radian, does anybody else make an aluminum aftermarket diaphragm for the 2441?
The cheapest way to go would be to rediaphragm the one with a 2445J, and then they would match and have decent HF extension, in addition, although exactly how close to a 2441 I don't actually know since I have read that the phase plugs also differ between the 2440 and 2441 so comments on this matter are solicited. But, presumably, the HF would extend several Khz beyond 10Khz, say at least to 15Khz(?) which would be enough for my purposes here.
The other issue I am considering is aluminum vs titanium. I would really like to go aluminum for SQ reasons, but cost is a factor, considering that two new 2441J diaphragms price out at around $270 apiece. The other major alternative is to use the Radian 1245-16 diaphragm in both, but there apparently has been considerable dissension in other forums regarding the merits of lack thereof of this diaphragm as a JBL replacement, although to give the Radian its due, the worst criticism of it that I've seen still admits it as the best of the aftermarket replacements.
I felt that for this application that I could accept a tradeoff in ultimate ruggedness because I wasn't planning to beat this speaker to within an inch of its life, so the Radian was still in the running from that perspective. Also, the JBL 2441J aluminum diaphragm diamond surround is apparently a significant weak point in high stress applications, as witness the cracked surround on the one driver I received. But that leaves HF frequency response where there appears also to be a difference of opinion, and there I found some information that clarifies the matter significantly for me, at least.
Radian uses the 1245 diaphragm in one of its own drivers, the 950 and includes a response graph, albeit considerably smoothed. This is presumably an optimal application for this diaphragm, but it is reasonable to assume that a similar response is obtainable in the JBL 244x family for which this diaphragm is also intended. But, comparing this graph with the one that JBL provided that superimposes the 2440, 2441 and TAD4001 responses on a JBL 2350 horn, some things become clear.
Above 2khz to about 10khz, the Radian graph shows a smooth 10db rolloff, above which it flattens out (on the average), but with several db of ripple to 20khz. However, this includes an additional 6db dip at 14khz, so the worst case falloff is around 16db, relative to midband. This is still several db more output than the 2440 in the 10-20Khz octave, but limits system efficiency for flat response to the 97db/w/m range if a response out to 20khz without significant dips using a passive xover is required. Comparatively speaking, the JBL 2441J diaphragm has at least 8db more output in this octave, so will support a 2-way passively xovered system with efficiency up to about the 105db/w/m range out to 20khz. In all cases, a CD type horn is assumed. With a smooth flare horn, even the Radian might achieve perhaps 103-104db/w/m on axis while avoiding 'titanium sound' (My basement blasters use all original 2445J's so I know whereof I write here).
So, I am still undecided between the Radian aftermarket diaphragms and shelling out for original D16R-2441s. This particular system does have a smooth tractrix flare horn but will be over 100db/w/m efficient. Comments are appreciated. Btw, besides Radian, does anybody else make an aluminum aftermarket diaphragm for the 2441?
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A few things here..
ALL of Radian's replacement diaphragms for other manufacturers are based on their alloy diaphragms, not pure aluminum like the 950 uses. So in fact the 1245-16 is better compared to their 850 PB, though even that is a significant "stretch" considering the different motors. (..and whatever horns they happened to have used for their published graphs.) Here is a french reseller's measurements for the 850:
http://www.cice-industrie.com/Compressions Radian Docs Xls/Radian 850 PB-8.pdf
There at least you can see that it isn't really the upper freq. response that is suffering for a 2 inch exit driver.
I believe that the reason most seem to like Radian's "sound" (if perhaps not their measurement spec.s), is due to their surround and lower freq. performance - i.e. there is more of it, though with an increase in non-linear distortion (..but not a hard distortion "wall" at fs like the metal surround diaphragms have).
IMO though you are "over thinking it" - just find-out Radian's return policy and purchase direct from them if it's suitable. If that works out then it's just a question of if you want to return them or not.
I don't see why not, Partsexpress has it and they are an authorized seller.
Parts-Express.com: Radian 1245-16 Diaphragm Fits Most JBL 1.5" and 2" 16 Ohm | lansing vc replacement hf high frequency mids midrange
and their return policy:
Parts-Express.com - No Hassle Returns
Parts-Express.com: Radian 1245-16 Diaphragm Fits Most JBL 1.5" and 2" 16 Ohm | lansing vc replacement hf high frequency mids midrange
and their return policy:
Parts-Express.com - No Hassle Returns
Hi, Scott G. -
Well, there is this from Radian's own description of the 1245 diaphragm:
Radian Audio manufactures a premium 4” compression driver diaphragm, model 1245, for its own model 950 PB compression driver. The Radian model 1245 also fits into several JBL™ 1.4” and 2” exit compression drivers, including model 2445, 2446, 375, 2440, 2441, 2447. 2450, 2451 and into Peavey™ models 44T and 44XT compression drivers. Available in 8 or 16 ohms.
Of course I would prefer to believe that the 1245 has a better HF response that shown for the 950. On reviewing the 950 spec, Radian doesn't indicate whether this measurement is shown for a plane wave tube or reference horn - I tended to assume the latter because the HF rolloff was not as steep as the plane wave tube measurment shown for the 1245 itself.
Well, there is this from Radian's own description of the 1245 diaphragm:
Radian Audio manufactures a premium 4” compression driver diaphragm, model 1245, for its own model 950 PB compression driver. The Radian model 1245 also fits into several JBL™ 1.4” and 2” exit compression drivers, including model 2445, 2446, 375, 2440, 2441, 2447. 2450, 2451 and into Peavey™ models 44T and 44XT compression drivers. Available in 8 or 16 ohms.
Of course I would prefer to believe that the 1245 has a better HF response that shown for the 950. On reviewing the 950 spec, Radian doesn't indicate whether this measurement is shown for a plane wave tube or reference horn - I tended to assume the latter because the HF rolloff was not as steep as the plane wave tube measurment shown for the 1245 itself.
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Yeah, that is kinda funny.
Their literature on the 950 says "pure aluminum"..
Here is cice's on the 950
http://www.cice-industrie.com/Compressions Radian Docs Xls/Radian 950 PB-8.pdf
Obviously with the additional impedance "bump" higher in freq. the sample measured has some rear chamber problems with pressure.
The 1245 also has this in the spec.s:
"DIAPHRAGM MATERIAL 0.003 heat-treated aluminum alloy"
..can't be both!
(..I'm inclined to believe now that they are one in the same, and that there is no "pure aluminum" diaphram for the 950. If that is the case then note similarities and differences in the freq. responses of the 950 vs. the 850..)
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My friend called me a week ago and mentioned comparison between Radian and Jbl diaphragms on 2440 drivers and 340hz Edgar horns. From his brief remarks I understood that Radian sounded better ,fuller on the bottom but didn't have an extension of original JBL diapers. I don't know what the final verdict was and what other aspects of the sound they evaluated but probably can get you in touch
with people directly involved. Regards, L
with people directly involved. Regards, L
Hi, Limono, Robh -
Yes, I would like to correspond with somebody who has actually had the opportunity to directly compare the Radians with JBL diaphragms. And, if Aquaplas can sufficiently mitigate the hardness of the JBL titanium 'pragms', at less than the cost of an original 2441 replacement that is something I would definitely consider.
Yes, I would like to correspond with somebody who has actually had the opportunity to directly compare the Radians with JBL diaphragms. And, if Aquaplas can sufficiently mitigate the hardness of the JBL titanium 'pragms', at less than the cost of an original 2441 replacement that is something I would definitely consider.
I have experience with the Radian, the 2440, 2445, and 2441 diaphragms in 2441 drivers.
All need a tweeter, the 2440 (smooth as butter) sounds best to me if crossed at/below 3K and above 500 and the Radian sounds better "wide range" as in using it wide open on top with a super tweeter blended in. The 2445 is the least desirable in sound quality. The 2441 is kinda in between the 2440 and the Radian.
All need a tweeter, the 2440 (smooth as butter) sounds best to me if crossed at/below 3K and above 500 and the Radian sounds better "wide range" as in using it wide open on top with a super tweeter blended in. The 2445 is the least desirable in sound quality. The 2441 is kinda in between the 2440 and the Radian.
I'd be interested in any guidance any of you could provide on the effective application of a pair of JBL2440 drivers in a 3 way Onken based system as I was just given a pair. I am not sure exactly what diaphragms are in these drivers but they appear to be new JBL 2445 which I understand may not be the best diaphragm for use in this driver in a small room in particular. Once I disassemble them for cleaning and a little fresh paint I should be able to identify exactly what the diaphragms are. (They have the diamond surround and appear to be titanium, but I am not completely sure.)
It seems based on advice from various sources that the 350Hz Edgar salad bowls might be the best horn to use with this driver long term in my small listening room. The fellow who gave me the drivers also has a set of fiberglass horns that he is going to give me as well, which I believe may be the horns originally used with a set of 2441..
It seems based on advice from various sources that the 350Hz Edgar salad bowls might be the best horn to use with this driver long term in my small listening room. The fellow who gave me the drivers also has a set of fiberglass horns that he is going to give me as well, which I believe may be the horns originally used with a set of 2441..
+1 on the above. I have JBL 2441 bodies and the Radian diaphragms. They sound much better in the mid range IMHO but I have to run a tweeter above 5Khz. I run the big Heil on top and the combo sounds great. I am crossing to the Lambda TD15X at 600hz. A friend of mine has the exact same set up but he runs the stock 2445 CDs and diaphragms, then went to the TrueXtent barrilium (SP) diaphragm. I like my set up better.
You should also look into the Cosmos wood horn by Dan Csomos. I've had two pairs of Edgarhorns and they sound great. But I got tied of locking my head in one position just to get imaging. And, the sound stage was not there the way I like it. The Cosmos horns have both imaging and sound stage in spades. They were disigned around the JBL 2445. P.S., Dan has a small room and they sound great in that room as they do in my big room.
I have tried both the Radian PB950 and the JBL 2445 in two types of horn: the radial horn Emilar EH-500 and the constant-directivity JBL 2360.
In both horns, I found the frequency response between the drivers to be remarkably similar. Many reports on better HF response on the Radian - in my measurements, this was not the case. None had much response below 600 Hz in the Emilar horn (I wouldn't cross it much below 800 Hz) - in the 2360 horn the 2445 had slightly better low frequency response than the Radian: down to about 400 Hz.
I tried the 2445 with both the orgiginal 16-ohms to diaphragms and the 2450SL aquaplased ti diaprahms. While the frequency response between those is quite similar, they sound differently - the 2450SL-diaphragm feels quite a bit smoother and less fatigueing.
IMO, the 2450SL-diaphragmed 2445 sounds better then the Radian. Both need about 10 dB HF boost for linear response - and both sounds somewhat harsh and "dull" when used this way, and (even in the 2360) are beamy above 8-10 kHz. IMO, they both need a supertweeter at about 8 Khz.
Wouldn't know about the 2440 or 2441 daphragms, though.
In both horns, I found the frequency response between the drivers to be remarkably similar. Many reports on better HF response on the Radian - in my measurements, this was not the case. None had much response below 600 Hz in the Emilar horn (I wouldn't cross it much below 800 Hz) - in the 2360 horn the 2445 had slightly better low frequency response than the Radian: down to about 400 Hz.
I tried the 2445 with both the orgiginal 16-ohms to diaphragms and the 2450SL aquaplased ti diaprahms. While the frequency response between those is quite similar, they sound differently - the 2450SL-diaphragm feels quite a bit smoother and less fatigueing.
IMO, the 2450SL-diaphragmed 2445 sounds better then the Radian. Both need about 10 dB HF boost for linear response - and both sounds somewhat harsh and "dull" when used this way, and (even in the 2360) are beamy above 8-10 kHz. IMO, they both need a supertweeter at about 8 Khz.
Wouldn't know about the 2440 or 2441 daphragms, though.
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This sounds like a good tip, any possibility of some contact information? My diaphragms are titanium and appear to be JBL 2445H types. Actually they sound significantly better in a lot of ways than what they replaced on a set of exponential horns pirated from a pair of 2441. (These are 800Hz horns) Radian 1245-16 diaphragms are well within reach, (US Speaker has these for $109 each) and I may have access to a set of JBL 2440 diapragms. I really do need response out to 8kHz as one of the high end options I can use is the JBL 2405 which don't work well below 7kHz or so... Currently I use 2402 on the top.. The XO is 2nd order butterworth at 800Hz, and 8kHz.
I assume the cosmos horn you mention is the one and same from the Lansing Heritage website? I should be able to get this replicated in fact. Anyone have any sense how this might compare to a conical?
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My thoughts. Paper-Maché horns. JMLC profile. Done.
Also check with these guys:
Sound Speaker Repair for frams.
They seem to be very knowledgeable and have plenty good stuff. I need to order a pair of 2404 'frams from them. Will let you know how that goes.
Also check with these guys:
Sound Speaker Repair for frams.
They seem to be very knowledgeable and have plenty good stuff. I need to order a pair of 2404 'frams from them. Will let you know how that goes.
Hi Mike,
Will look at the horns.. I'm somewhat familiar with these replacement diaphragms and while they are functionally equivalent I feel that they would be a big step down from the JBL D16R2445 I am currently running. I have used some in the past with OK, not stellar results. IMHO these are just fine in club sound installations and roller rinks, but I'd like something a little smoother in my listening space.
In the case of diaphragms I suspect you do to a fair extent get what you pay for, and really good ones are expensive.
The Radian 1245-16 ($109) is reputedly significantly better sounding than the D16R2445 I currently run and is about half as much as the JBL D16R2440 (~ $244.00) which is another well regarded option for these drivers.
Will look at the horns.. I'm somewhat familiar with these replacement diaphragms and while they are functionally equivalent I feel that they would be a big step down from the JBL D16R2445 I am currently running. I have used some in the past with OK, not stellar results. IMHO these are just fine in club sound installations and roller rinks, but I'd like something a little smoother in my listening space.
In the case of diaphragms I suspect you do to a fair extent get what you pay for, and really good ones are expensive.
The Radian 1245-16 ($109) is reputedly significantly better sounding than the D16R2445 I currently run and is about half as much as the JBL D16R2440 (~ $244.00) which is another well regarded option for these drivers.
The phase plug geometry is quite different between the 2440 and the 2445 drivers so I am not sure whether your observations could be applied directly to the 2440 or not. Several disparate sources both here at diya and elsewhere have indicated that the Radian is probably the hot ticket in the range I intend to run them.
That said the D16R2445 diaphragms currently in my 2440 sound surprisingly good if not quite perfect. There is a slight metalic coloration which is much less pronounced than the unknown diaphragms (definitely are not from Sound Speaker Repair) in the 2420s they replaced. I am hoping an upgrade in diaphragms will further reduce this.
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Right-O. I have not tried any of these after-market frams, but for the price I'm willing to chance it. I did buy genuine GPA frams for the 288s.
I have a pair of old Fane bullet tweeters that I can not find frams for. Even Fane say no way, too old. But I think the 2404/5 frams will fit. So I'm willing to try one. But not at JBL prices!
Will certainly be curious to know how the Radian frams sound. Some guys love that mylar surround that Radian/Emilar did. I didn't care for it in the Radians I have, nor in any of the Altec Symbiotic diaphragms. But maybe they've gotten better - technology marches on! It's pretty easy to measure the distortion differences of the different frams.
I have a pair of old Fane bullet tweeters that I can not find frams for. Even Fane say no way, too old. But I think the 2404/5 frams will fit. So I'm willing to try one. But not at JBL prices!
Will certainly be curious to know how the Radian frams sound. Some guys love that mylar surround that Radian/Emilar did. I didn't care for it in the Radians I have, nor in any of the Altec Symbiotic diaphragms. But maybe they've gotten better - technology marches on! It's pretty easy to measure the distortion differences of the different frams.
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