Swap 2441 Diaphragm into 2445?

[Steve Gonzales]

I want to know if there would be any problems doing this?. I like the sound that aluminum diaphragms produce and I can't seem to find a decent pair of Alnico bodies. Seems like Ferrite bodies are easier to come by. Anyone know if this is a direct fit ?. Thank you, Steve G.

[Mr. Widget]

It's a direct fit. I have wondered for some time if a 2445 motor/phase plug/throat would sound the same as the 2441 when they both have the same diaphragm. I have never had both here at the same time and no one has reported on doing such a comparison.


Widget

[scott fitlin]

It's a direct fit. I have wondered for some time if a 2445 motor/phase plug/throat would sound the same as the 2441 when they both have the same diaphragm. I have never had both here at the same time and no one has reported on doing such a comparison.


WidgetSome time ago, I had told of this comparison.

At another buisiness down in my area, that also has sound, they changed from the 2441,,s to 2445,s. The 45,s sounded good, but a bit hard, so they put an aluminum phragm into the 45. It fits and it works, sweeter up top then the Ti part, but still didnt sound quite like the alnico driver. Wasnt bad though, just not exactly like the 41. A 41 with its alnico motor still sounds crisper, and has that certain bite that I have only heard from alnico/aluminum drivers. OTOH, the 2445 fitted with either the 41 or 45 diaphragm seems to have a chunkier sounding lower mid. Piano notes had more body.

[edgewound]

It's a direct fit. I have wondered for some time if a 2445 motor/phase plug/throat would sound the same as the 2441 when they both have the same diaphragm. I have never had both here at the same time and no one has reported on doing such a comparison.


Widget

A 2446 has the advanced phase plug of the 2450 with a 2" exit. A good compromise would be the 2450HS diaphragm (titanium/aquaplas) on the 2446 motor. Less expensive than the aluminum diaphragm.

[subwoof]

It's actually the 2450SL and I have installed a few of them into the old phaseplug ( 40,41,45 ) motors with good results. The coating really tames the "trashcan cover" issue around 2.5K and works great for stage monitors.

All my 1.5 drivers use them except ( of course ) the 2435Be

Also the 2441 installed in the 2445 sounds just like the 2441. I did this for a studio whose alnico motors went south in 1985 and no replacement was handy.

Now of course the low power tube distortion purists will say that the difference in magnetic material, flux density, magnetic gap field, throat material ( some 2445's had bakelite, some were aluminum ), color and of course the alignment of the dylithium crystals in the transmorgifier chamber is noticable but that difference is akin to a mouse passing gas 3 rooms away during a pink floyd passage.

Had to say that one. last night was the techie beer night and it was one of the topics...

:cheers:

sub

[Guido]

A 2446 has the advanced phase plug of the 2450 with a 2" exit. A good compromise would be the 2450HS diaphragm (titanium/aquaplas) on the 2446 motor. Less expensive than the aluminum diaphragm.

Interesting! What exactly was optimized with the 2446?

[speakerdave]

Coherent Wave phase plug "for increased high frequency output."

[edgewound]

Coherent Wave phase plug "for increased high frequency output."

Yep...what he said...out to about 18khz.

And Subwoofs correction is right, too, D8R2450SL.

2447 and 2451 both have the 2" snout removed for 1.5" exit, with the same coherent wave phase plug.

[Mr. Widget]

The coating really tames the "trashcan cover" issue around 2.5K...

Also the 2441 installed in the 2445 sounds just like the 2441. I did this for a studio whose alnico motors went south in 1985 and no replacement was handy.

Now of course the low power tube distortion purists will say that the difference in magnetic material, flux density, magnetic gap field, throat material ( some 2445's had bakelite, some were aluminum ), color and of course the alignment of the dylithium crystals in the transmorgifier chamber is noticable but that difference is akin to a mouse passing gas 3 rooms away during a pink floyd passage.I've often wondered how one realigns their dylithium crystals while they are still in the transmorgifier chamber... I've only been successful when the crystals were outside of the chamber...

I would bet that the 2445 motor and 2440/1 motors would sound essentially identical... I have never been able to consistently hear a difference between the alnico and ferrite 2405s for example. Now that isn't to say that you won't hear a difference in a comparison between pair A and pair B... there are variations between lots and age can have an effect, but taken as a group I haven't heard a difference.

As for a 4" diaphragm being run up to 18KHz... I have issues with this. For PA use, go ahead, knock yourself out... it will work, and in many cases may be the best solution. But for the fanatical trying to get the best possible performance, these large drivers just don't cut it way up top. Adding magnetic horsepower and beryllium diaphragms ala the TAD approach will get you the output up top but it is still all mass breakup distortion and not usable in my opinion... a coated diaphragm may lesson the affects of the mass breakup distortion, but it is still there and anyone concerned about the orientation of their dylithium crystals should add a proper tweeter.

To a lesser degree this generally applies to the 1.75" diaphragmed, 1" drivers too.


Widget

[edgewound]

As for a 4" diaphragm being run up to 18KHz... I have issues with this.

Widget

Well....that's what JBL advertised for the new phase plug...point being it's better that the old one, that's all....scrutinize it all you want...the 2450 was used in hi end Studio Monitors such as the coaxial PAS TOC a 2-way...and some other's I'm sure. They also used the TAD

[norealtalent]

Partial... a coated diaphragm may lesson the affects of the mass breakup distortion, but it is still there and anyone concerned about the orientation of their dylithium crystals should add a proper tweeter.



Widget

When I use dylithium crystals, I just add water.:p

[Mr. Widget]

....scrutinize it all you want...the 2450 was used in hi end Studio Monitors such as the coaxial PAS TOC a 2-way...and some other's I'm sure. They also used the TADWell a lot of people do a lot of things... TAD sold factory designed monitors at very high prices... none had tweeters. I have used both the TAD 4001 and the 4003... I think both are improved with the addition of tweeters. I have also used the JBL 2441 and like it a lot too... though virtually no one claims that it doesn't require a tweeter.

FWIW: TAD's studio monitors... all were two-ways with no tweeter... and like the two-way 4430/35 they are all discontinued. Could be a coincidence... could be a related fact... my point is simply, if you are going for the best possible sound, at least try adding a tweeter... you will either hear an improvement or you won't. If you do great... if not sell the tweeters after your experimenting... it isn't about getting to 20KHz... but how well you do 15KHz.


Widget

[edgewound]

Well a lot of people do a lot of things... TAD sold factory designed monitors at very high prices... none had tweeters. I have used both the TAD 4001 and the 4003... I think both are improved with the addition of tweeters. I have also used the JBL 2441 and like it a lot too... though virtually no one claims that it doesn't require a tweeter.

FWIW: TAD's studio monitors... all were two-ways with no tweeter... and like the two-way 4430/35 they are all discontinued. Could be a coincidence... could be a related fact... my point is simply, if you are going for the best possible sound, at least try adding a tweeter... you will either hear an improvement or you won't. If you do great... if not sell the tweeters after your experimenting... it isn't about getting to 20KHz... but how well you do 15KHz.


Widget

I'm not disagreeing with you...Most all the big monitors are discontinued now:( ...I think we've had that discussion before....about big studios going away...with big monitors going away....kinda sad...all about the home project studios now...blah...blah:blah:

[Mr. Widget]

Yeah my observation about obsolescence kinda derailed my argument about the quality of highs being more important than simply "getting there".


Widget

[Steve Gonzales]

Yeah my observation about obsolescence kinda derailed my argument about the quality of highs being more important than simply "getting there".


Widget Hey, this is a forum right?, no sweat!. I appreciate everyone's opinions and technical help, thank you all.

I want to shed a little more light on 'mass breakup distortion'. Here is a picture of the 2435hpl beryllium diaphragm (top) compared to another metal (Titanium) at 14.5khz. These are from the JBL Professional Site. These are actual pictures representing the problems a large diaphragm has reproducing UHF soundwaves. Very interesting indeed. Thanks once again for your input, Steve G.

[Steve Gonzales]

When I use dylithium crystals, I just add water.:p

I drink Folger's too :D .