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Mr. Widget
06-23-2005, 12:14 AM
This thread will show the on and off axis response of all four of JBL's ring radiator tweeters. There seems to be some confusion over these so here is a mini background. All four tweeters can use the same diaphragms and have the same motor structure. There is an alnico and ferrite version. After having measured several of each tweeter in both motor types I am certain that there is a fair amount of unit to unit variation, but not due to magnet type.

The first model of this series was the 075 "Bullet Tweeter". There is also the Pro variant the 2402 and the ferrite version, the 2402H. This model has a the heaviest diaphragm of the three and is capable of operating over the widest frequency range. It also has the most focused dispersion pattern.

The next model offered was the 077 "Slot Tweeter" and it's Pro variant, the 2405. Later there was the ferrite 2405H. This model has the lightest diaphragm and offers the widest dispersion pattern and produces the highest frequencies.

The third model offered by JBL was the 076. There was also a Pro variant offered, the 2403 in alnico and the 2403H in ferrite. It was originally designed specifically for the L220. It uses a unique diaphragm. I believe that it has a moving mass that is between the 075 and 077.

The final model offered by JBL was the 2404H. It uses a mini butt cheek bi-radial horn. It uses the 2405 diaphragm, but is usable down to much lower frequencies than the 2405.


Here is an on axis plot comparing two brand new 2402Hs.

Mr. Widget
06-23-2005, 12:15 AM
This plot shows the off axis performance of a 2402H.


On axis is in Red
15° off axis is in Blue
30° off axis is in Green
45° off axis is in Purple

Mr. Widget
06-23-2005, 12:17 AM
Here is the plot of a 2405.


On axis is in Red
15° off axis is in Blue
30° off axis is in Green
45° off axis is in Purple

Mr. Widget
06-23-2005, 12:18 AM
Here is a plot of the 2403H (076 Cat Eye)


On axis is in Red
15° off axis is in Blue
30° off axis is in Green
45° off axis is in Purple

Mr. Widget
06-23-2005, 12:19 AM
Here is a plot of a 2404H.


On axis is in Red
15° off axis is in Blue
30° off axis is in Green
45° off axis is in Purple

Mr. Widget
06-23-2005, 12:21 AM
Here is a comparison we did between a pair of 2404Hs. One was labled 2404H and the other 2404H-1.

yggdrasil
06-23-2005, 02:34 AM
Widget, this is great.

The 2402 rolls off earlier than the 2405. Is this due to the horn and / or diaphragm? Have you tested 2402 with 2405 diaphragm?

Just curious?

johnaec
06-23-2005, 05:51 AM
Here is a comparison we did between a pair of 2404Hs. One was labled 2404H and the other 2404H-1.Thanks for posting those! I believe the 2404H-1 uses the 2402 diaphragm and the 2404H uses the 2405 diaphragm.

John

Robh3606
06-23-2005, 07:34 AM
Excellent Widget!!!

Thanks for posting those I have to save this thread for sure! It confirms some of my subjective impression when compairing the 2404/2405 when I was doing mock-up's for my 4344's. The 2405's seemed to have more detail and clarity up high with percusion and cymbals than the 2404. When I was building the 4344's I was tempted to try the 2404's but felt the 2405's were better in this respect and went with the stock set-up. Amazing how consistant the 2404's are off axis!!! Looking at the 076 you can keep them. I would just use the slot avoid the peaked response and save some bucks!

Rob:)

Zilch
06-23-2005, 11:04 AM
It's reassuring to note that, at least technically, JBL's been givin' us the straight poop about this stuff, it would appear. :D

076 DOES have "charisma" going for it.

[I'm over-invested in charisma, obviously....]

Biradial is real, not hype.

[Got my new 2405 diaphragms right here.... ;) ]

Steve Schell
06-23-2005, 11:36 AM
Thank you Mr. Widget for your very well and carefully done measurements. I agree that this thread is a keeper.

Just curious; what was the input power used for the measurements, and the distance of the measurement mic?

Mr. Widget
06-23-2005, 11:41 AM
The distance was 1m. The power was milliwatts. The SPL measurement is calibrated, so you should be able to get a pretty close answer by using JBL's published sensitivity numbers. We never measured the actual power level. The power level chosen was based on a comfortable listening level during the tests.

Widget

Steve Schell
06-23-2005, 11:57 AM
Thanks. I dislike doing 1W tests myself, as they are so doggone loud with high sensitivity drivers. It is also unnecessary, as the curves at lower levels seem to perfectly track the higher power ones.

mikebake
06-23-2005, 01:58 PM
Nice, Widgie. I wish I hadn't parted with my mint 2405's or tent sale 2404's now. The slot has always been one of my favorite JBL drivers ever since meeting a pair of L300's in the 70's.

Oldmics
06-23-2005, 09:59 PM
Come on Widget

Put the T.A.D. ET 703 plot in there for comparison.

Inquiring minds want to know.

Oldmics

Mr. Widget
06-23-2005, 10:59 PM
Come on Widget

Put the T.A.D. ET 703 plot in there for comparison.

Inquiring minds want to know.

Oldmics

But it's not a "ring radiator".;)

Widget

Ian Mackenzie
06-24-2005, 12:15 AM
Somewhere I have a design for a notch filter to improve the 2405, that peak below 8000 looks enormous.

Ian

Cyclotronguy
06-24-2005, 09:49 AM
As I recall the 703 on axis has a very broad peaked resonse around 15kHz, something to the tune of 10 dB, that must be addressed. Maybe Widget can enlighten us with off axis scans.

Cyclotronguy

Mr. Widget
06-24-2005, 11:30 AM
Yeah, the TAD does have a rather un-textbook like on-axis curve. The pair of ET-703s I currently have are stuck in these cabinets and I can't stop listening to them long enough to pull the tweeters out and do some measurements of them. I have ordered veneer samples and will eventually need to pull out the drivers and finish the speakers. I'll post the curves then.

Widget

Maron Horonzakz
06-27-2005, 07:07 AM
TAD Et703......Being a diffraction type horn I would like to see off axis poler plots of this tweeter.

Jan Daugaard
06-27-2005, 07:18 AM
Hi Widget,

there is a fifth ring radiator: The 2407H / 2407J which JBL is using from 1200 Hz. Any chance of some measurements for this new ring radiator?

Jakob
06-29-2005, 12:21 AM
Nice work Widget!

What driver and horn are You using for lows and mids?

Thank You for the measurments!

BR: Jakob

Mr. Widget
06-29-2005, 09:33 AM
Hi Widget,

there is a fifth ring radiator: The 2407H / 2407J which JBL is using from 1200 Hz. Any chance of some measurements for this new ring radiator?

I don't know anything about the 2407, but after doing a quick search on the JBL Pro site, it appears to be a 1.5" light weight compression driver with unique diaphragm. I would assume it is more closely related to the drivers we tested here:

http://audioheritage.org/vbulletin/showthread.php?t=6050

It does not appear to be a ring radiator.

Widget

Mr. Widget
06-29-2005, 09:35 AM
What driver and horn are You using for lows and mids?

The woofer is a JBL 1500AL and the mid driver is TAD TD4003 on a TAD TH4003 horn clone.

Widget

stevem
06-29-2005, 09:49 AM
How do you like your 1500AL woofers? Can you compare their performance to other JBL woofers like the 2235H or the 1401Nd? What size enclosure are you using? Thanks!

Ken Pachkowsky
06-29-2005, 01:21 PM
Wow, thats a kick in the butt. So much for adding these 2403's to my Westlakes. I will leave them stock 2405's.

Thanks Widget

Ken

Ian Mackenzie
06-29-2005, 02:17 PM
I would still try them....trust your ears..then read the graphs....not visa versa.

The Doctor

Zilch
06-29-2005, 02:26 PM
I wouldn't be surprised if Mr. Widget used 'em hisself.... :p

[The look alone is compelling....]

John
06-29-2005, 02:37 PM
I had a feeling the cat eyes would not be much different to the 2405. I mean if it was that much better than the 2405 you would think JBL would not drop it from production. Most likely westlake wanted a ultra hf unit on their top of the line system and figured the cat eye would look a bit more unique than the common 2405??? :blah:

Ian Mackenzie
06-29-2005, 04:24 PM
The lower mass and hence vastly superior transient capabilty is the issue.

You can EQ the crap out of any driver/ horn and it will look flat to the naked eye but that's not how it sounds.

The Doctor

Mr. Widget
06-29-2005, 05:37 PM
The lower mass and hence vastly superior transient capabilty is the issue.

You can EQ the crap out of any driver/ horn and it will look flat to the naked eye but that's not how it sounds.


I agree... the lower mass of the 077/2405 has my vote. We did run a measurement of the Cat eye with a 2405 diaphragm. It had essentially the same raggedness as the stock Cat eye, but with a slightly extended top end.

I will audition them at some point. While curves do not lie, they don't tell the whole story.

Widget

slxrti
07-01-2005, 09:52 PM
To My ears the 2405 are brighter than the 2404 (The curves bear this out).

The 2405 give up Vertical dispersion performance for Horizontal

Using the proper crossover/eq the response of the 2404 can be made flat,
with great off axis performance.


Slxrti

Steve Gonzales
07-02-2005, 09:42 PM
I would still try them....trust your ears..then read the graphs....not visa versa.

The Doctor You have infused this little "test" session with a HUGE dose of WISDOM! You must listen to these tweeters (076-2403's) before passing judgement, they are SWEET, and yes, I've owned 075's and 077's too, both very good in their own right also. Someone commented that Westlake put 076-2403's in their $125K studio monitors because the looked cool?. No doubt that they do but they did it because the darn things are VERY GOOD. But, if anyone wants to get rid of their 076's, send them to me and I will GLADLY "dispose" of them for you ;) . SG.

slxrti
07-02-2005, 11:38 PM
You have infused this little "test" session with a HUGE dose of WISDOM! You must listen to these tweeters (076-2403's) before passing judgement, they are SWEET, and yes, I've owned 075's and 077's too, both very good in their own right also. Someone commented that Westlake put 076-2403's in their $125K studio monitors because the looked cool?. No doubt that they do but they did it because the darn things are VERY GOOD. But, if anyone wants to get rid of their 076's, send them to me and I will GLADLY "dispose" of them for you ;) . SG.

I would have thought the Westlake's used either passive or active eq to flatten the on axis response.



I agree they look cool, I do doubt if that was the reason Westlake used them.


Slxrti

scott fitlin
07-03-2005, 12:29 AM
To My ears the 2405 are brighter than the 2404 (The curves bear this out).

The 2405 give up Vertical dispersion performance for Horizontal

Using the proper crossover/eq the response of the 2404 can be made flat,
with great off axis performance.


SlxrtiI bought some 2405,s to replace my 2404,s and also found them to be brighter, and sharper sounding than the 2404. I find the 2404 has a soft sounding top end! Found out I prefer it to the 2405!

Ian Mackenzie
07-03-2005, 01:10 AM
You have infused this little "test" session with a HUGE dose of WISDOM! You must listen to these tweeters (076-2403's) before passing judgement, they are SWEET, and yes, I've owned 075's and 077's too, both very good in their own right also. Someone commented that Westlake put 076-2403's in their $125K studio monitors because the looked cool?. No doubt that they do but they did it because the darn things are VERY GOOD. But, if anyone wants to get rid of their 076's, send them to me and I will GLADLY "dispose" of them for you ;) . SG.

Hi Steve,

Well this is the thing I like about audio.

There's the romance and there's the quirky logic to it all.

You never know what your going to get until you actually try it.

Another case in point was the post I put up recently in the 4343 crossover modifications thread where a member was hoaxed into running his 4343's in full passive mode for a taste test using his Passlabs X250 as the prime amplifier, something he had never previously done as his system was always bi amped. Up till this point the notion was held that it was difficult to imagine how his system could sound better.

Basically he back flipped with a long email at 2.00 am in the morning, now enlightened with enthusiasm and enjoyment.

Its a case of just trying different things and hearing it for yourself.

Ian

Ken Pachkowsky
07-03-2005, 08:49 AM
Thanks for the input on the 2403's guys. I will go ahead and test them when the time comes. I finaly get home after a month on the road this Tuesday and hope to have the Ians designed 5-way xover up and testing by August.

Ken

Steve Gonzales
07-03-2005, 11:10 AM
http://www.westlakeaudio.com/Speakers/Professional_Series/sm1.jpg


The SM-1 is a 5-way, high power, phase coincident monitor. Designed as the ultimate in high power monitoring, the SM-1 offers 6 dB more headroom at low frequencies than most studio monitors. While its physical dimensions and weight may preclude its use in many existing facilities, any substantial investment in updated facilities or new room designs should include serious consideration of this monitor. Careful selection of drivers, combined with a unique mechanical configuration and phase aligned crossovers, provide an acoustic depth of field unattainable with conventional designs. The SM-1 offers the user a choice of powering their system in a bi-amp or passive tri or quad amp set-up with the MRX-2, 2-way active crossover, a quad-amp or passive pent or sext amp set-up with the SM-1X, 4-way active crossover or fully active pent-amp set-up with both the SM-1X and MRX-2 being used. All this and more make the SM-1 the world's most powerful production reference monitor system.


Specifications (http://www.westlakeaudio.com/Speakers/Professional_Series/body_sm-1.html#)

Buy Now (http://www.westlakeaudio.com/Speakers/Dealers/dealers.html)

Accessories (http://www.westlakeaudio.com/Speakers/Professional_Series/accessories.html)

norealtalent
07-03-2005, 11:35 AM
[QUOTE=Mr. Widget]I agree... the lower mass of the 077/2405 has my vote. We did run a measurement of the Cat eye with a 2405 diaphragm. It had essentially the same raggedness as the stock Cat eye, but with a slightly extended top end.

I will audition them at some point. While curves do not lie, they don't tell the whole story.

[QUOTE=Mr. Widget]...Not all specs are created equally...

Yeah, Westlake throws tweeters in their world class monitors just because they look cool, while JBL posts inferior specs derived from multimillion dollar research facilities. For sure, not all specs are created equal. I'll go by the ones JBL provides, you know, the ones radiating from these "ragged" cats eyes and extending their warmth into my spectrum analyzers, EARS!!!;)

Steve Gonzales
07-03-2005, 12:07 PM
[QUOTE=Mr. Widget]I agree... the lower mass of the 077/2405 has my vote. We did run a measurement of the Cat eye with a 2405 diaphragm. It had essentially the same raggedness as the stock Cat eye, but with a slightly extended top end.

I will audition them at some point. While curves do not lie, they don't tell the whole story.

[QUOTE=Mr. Widget]...Not all specs are created equally...

Yeah, Westlake throws tweeters in their world class monitors just because they look cool, while JBL posts inferior specs derived from multimillion dollar research facilities. For sure, not all specs are created equal. I'll go by the ones JBL provides, you know, the ones radiating from these "ragged" cats eyes and extending their warmth into my spectrum analyzers, EARS!!!;) Don't confuse me with the facts, my mind is made up !:D

Robh3606
07-03-2005, 12:17 PM
"I would still try them....trust your ears..then read the graphs....not visa versa."

Hello Ian

I would too if I had them. As far as trust your ears and then the graphs only if your budget will allow it;) Them baby's are expensive!

"Yeah, Westlake throws tweeters in their world class monitors just because they look cool, while JBL posts inferior specs derived from multimillion dollar research facilities. For sure, not all specs are created equal."

Look at the 4300 series monitors, all of them, what do you see?? 2405's
With both drivers available why is that?? Westlake picks and chooses from any and all manufacturers for the best drivers for their applications. Why did they choose the 2403 over a 2405?? I think it has more to do with design philosophies.

If you look at the JBL crossovers they are high order while the Westlakes as minimum phase would be lower order. The Westlakes use a 1" driver and have the 2403 above where the rising response would work very nicely against the roll off in the 1 ' driver. You also have the directivity at crossover with the 1" horn to consider. I wouldn't be surprised if the 2403 matches better at crossover than the 2405. I am just blowing smoke here but I think what we really have are 2 drivers that were specifically engineered for their intended use. The 2405 was JBL's choice for their monitors and better meet their design philosophies. The 2403 meets the Westlake driver reqiurements with it's unique attributes better than a 2405 for the SM1. They each have there own strengths and will shine and give their best when they are used as they were designed to be.

Rob:)

norealtalent
07-03-2005, 02:20 PM
[QUOTE=Robh3606]

"I would still try them....trust your ears..then read the graphs....not visa versa."

[QUOTE=Steve Gonzales] Don't confuse me with the facts, my mind is made up !

I have never tried doing it but I have read everything there is on brain transplants. I am now offering lessons for pre-med students and need a patient for demonstrating my qualifications to the class.
Any volunteers???http://audioheritage.org/vbulletin/images/smilies/banghead.gif

slxrti
07-03-2005, 03:38 PM
[QUOTE=norealtalent][QUOTE=Robh3606]

"I would still try them....trust your ears..then read the graphs....not visa versa."

I agree, if I can fine neutral program material and I a perfect audio memory of what it should sound like.



Since I have neither I would use my hears to fine tune to a particular taste, then quantify the changes using measurements.



slxrti

Robh3606
07-03-2005, 05:55 PM
"I would still try them....trust your ears..then read the graphs....not visa versa."

Norealtalent, Slxrti

Double mis-quote nice;) Take a look through the thread.

"Since I have neither I would use my hears to fine tune to a particular taste, then quantify the changes using measurements."

I do the exact opposite I measure and then fine tune. The measurement confirms the engineering. If the engineering isn't right your wasting your time.

Rob:)

norealtalent
07-03-2005, 06:02 PM
Been there, done that, got the t-shirt, moved on to bigger and better things...

4350's for the next round:D

slxrti
07-03-2005, 06:46 PM
"I would still try them....trust your ears..then read the graphs....not visa versa."

Norealtalent, Slxrti

Double mis-quote nice;) Take a look through the thread.

"Since I have neither I would use my hears to fine tune to a particular taste, then quantify the changes using measurements."

I do the exact opposite I measure and then fine tune. The measurement confirms the engineering. If the engineering isn't right your wasting your time.

Rob:)

That's what I meant!!!!:eek:

spkrman57
07-03-2005, 06:50 PM
I have 075's and even crossed over at 2.4khz(N2400) to the D123, I have to work hard to find faults with that driver even though it is scoffed at many times.

I like the idea of getting the lighter diaphrams for them sometime in the future, but the little bit of listening I have used these for I find them quite pleasant sounding at the lower and medium levels.

I understand that they can sound quite "shouty", but I can find faults in a lot of drivers, not to mention my smallish room acoustics can make some of the best speaker systems I put together sound bad compared to when I might take them to friends houses with large rooms(my house when I win the lotto).

So I guess we are just picking the best of the best right?????

Ron (I guess I just wore out my 2 cents worth!!!)

Steve Gonzales
07-03-2005, 07:07 PM
[QUOTE=Robh3606]

"I would still try them....trust your ears..then read the graphs....not visa versa."

[QUOTE=Steve Gonzales] Don't confuse me with the facts, my mind is made up !

I have never tried doing it but I have read everything there is on brain transplants. I am now offering lessons for pre-med students and need a patient for demonstrating my qualifications to the class.
Any volunteers???http://audioheritage.org/vbulletin/images/smilies/banghead.gif Thanks for the offer, but my mind is made up, I'll just listen to my "ragged" 076's making SWEET harmonies on my "spectrum analyzers", ALL THREE PAIRS :bouncy:

Ian Mackenzie
07-03-2005, 08:57 PM
Steve,

Please let us know what happens.

Ian

Roddyama
07-15-2005, 12:46 PM
I don't know if this is a feature that extends to all of the above mentioned drivers or not, but I found the 077/2405 to have a very flat impedence curve in its "usable" range. It makes for very simple and predictable hi-pass filters.

Mr. Widget
07-16-2005, 01:58 PM
I should have posted these impedance plots earlier in this thread... I'm sorry that I overlooked it. I have posted it elsewhere but to make this thread more complete here it is again.

Here are impedance plots of 4 slot tweeters 2 are labeled 8 ohm and are alnico 077s and two are older 2405 alnicos labeled 16 ohms. All four drivers are in exceptional condition and have their original diaphragms and seals. As JBL technical literature states all of these drivers use the same diaphragms and therefore should have the same impedances. The differences seen in these plots shows a random sampling of these drivers exhibiting slight production differences.

Red 077 "8 ohm"
Purple 077 "8 ohm"
Green 2405 "16 ohm"
Blue 2405 "16 ohm"

Zilch
10-31-2005, 12:08 PM
Diminutive (2.75" diameter) neodymium 2407H has 1" threaded throat to mount on PT waveguides or OASR horns. Throat adapter (lower left) will mate them with 1.5" versions.

Pick your desired dispersion pattern.

Compare size to 2418H-1 in photos.

More info here: http://audioheritage.org/vbulletin/showthread.php?t=4695

Jan Daugaard
10-31-2005, 12:49 PM
Hi Zilch,

could we have a close-up photo of the front (= the part facing the horn) of the 2407H?

Thanks in advance!

Jan D.

John Sheerin
10-31-2005, 03:48 PM
According to DJK at AA (and it's obvious if you look at them), the 2406 is made by BMS - it's the H4550. The 2407 is the H4552ND. Cheaper to buy the BMS parts, I think...

scott fitlin
10-31-2005, 03:56 PM
According to DJK at AA (and it's obvious if you look at them), the 2406 is made by BMS - it's the H4550. The 2407 is the H4552ND. Cheaper to buy the BMS parts, I think...BMS H4552ND is $145.00 on this site! http://www.woodhorn.com/BMS/bms_4552nd.htm

Zilch
10-31-2005, 04:01 PM
Could we have a close-up photo of the front (= the part facing the horn) of the 2407?It's the standard SS mesh. I can't see inside. :( Maybe after dark with proper illumination.

RTA curves as follows:

1) OASR horn
2) El Cheapo PT-F95
3) PT-F1010 w/adapter
4) PT-F64 w/adapter, inline constrictions
5) PT-F64 w/adapter, opposed constrictions

Note: I have two PT-F64 waveguides. Pins in the adapter mate to holes in the waveguide flange to orient throat constrictions in the adapter with those in the waveguide itself. One waveguide is drilled one way, the other, opposite. I've shown results with both orientations. Opposed constrictions, the orientation used on all of the other waveguides, the last pic below, is the apparent correct one. Ahhhh, SCIENCE!

2407H is "Plug 'n' Play" on 2) and 5), above, probably. Others require compensaton. I'll try on any compatible horn/waveguide anyone's willing to send me. No 2360's or Everest horns, please.... ;)

Bear in mind, this is one unit only, and we don't know if the polar responses for these waveguides hold up. Listening to the pink noise, it seems to me like they do.

I'll ask Mr. Widget to run the REAL tests on these for this thread, his time and interest permitting.... :)

Zilch
10-31-2005, 04:12 PM
According to DJK at AA (and it's obvious if you look at them), the 2406 is made by BMS - it's the H4550. The 2407 is the H4552ND. Cheaper to buy the BMS parts, I think...Unless my metric conversions are FUBAR, they're different diameters. The construction and mounting is different, too.

Polyester diaphragm?

"The 2407H incorporates a center-clamped titanium diaphragm."

http://www.jblpro.com/pub/cspels/CBT4%205-5-03.pdf

"Radial slot phase plug" here:

http://www.jblpro.com/Control300/PDF/C322%20Prelim%20SS%200508C.pdf


It's also been claimed that 2407 is a repackaged 035tiA. :p

Don't think I'd use 2407H in place of 2426H or 2431H just yet, nope....

edgewound
10-31-2005, 04:17 PM
According to DJK at AA (and it's obvious if you look at them), the 2406 is made by BMS - it's the H4550. The 2407 is the H4552ND. Cheaper to buy the BMS parts, I think...

I think there's a serious engineering management problem that needs to be addressed at Harman/JBL...one of the world's foremost audio transducer/system manufacturer's is using another vendors drivers in their new systems....and this isn't the first time either. The early TR systems employed Eminence woofers until the dealer network figured it out....then they stopped, and made their own stamped frame woofers....because they could. Is this really Lansing Heritage as we know it? Anymore....it's just a becoming a brand name led bt a multinational sourcer named "Harman International". It wouldn't surprise me if BMS becomes a Harman division, like Audax.

edgewound
10-31-2005, 04:20 PM
Unless my metric conversions are FUBAR, they're different diameters. The construction and mounting is different, too.

It's also been claimed that 2407 is a repackaged 035tiA. :p

Don't think I'd use 2407H in place of 2426H or 2431H just yet, nope....

No...that would be the 2412H/-1....repackaged 035Ti/A

The 2406 and 2407 both are ring radiators with 2406 with polyester/mylar diaphragms, curiously similar....very similar... to the BMS.

Zilch
10-31-2005, 04:38 PM
The 2406 and 2407 both are ring radiators with with polyester/mylar diaphragms, curiously similar....very similar... to the BMS.Don't MAKE me open these up, now. :no:

We'll leave the actual internal construction for Mr. Widget to discover.... :p

scott fitlin
10-31-2005, 04:41 PM
No...that would be the 2412H/-1....repackaged 035Ti/A

The 2406 and 2407 both are ring radiators with 2406 with polyester/mylar diaphragms, curiously similar....very similar... to the BMS.To my eyes, the BMS driver looks just like the JBL driver but without the threaded flange!

Now If JBL is really using a BMS driver, it isnt difficult to have their driver made with the threaded flange and chamfered front! But the backcaps look identical! Even the connectors!

BMS could make it for JBL to JBL specs, and possibly the only difference is the diaphragm material.

Zilch
10-31-2005, 05:06 PM
To my eyes, the BMS driver looks just like the JBL driver but without the threaded flange!

Now If JBL is really using a BMS driver, it isnt difficult to have their driver made with the threaded flange and chamfered front! But the backcaps look identical! Even the connectors!

BMS could make it for JBL to JBL specs, and possibly the only difference is the diaphragm material.It looks more like the BMS in the coax I linked to above. Still, the 0.6" difference in diameters is significant, as is the difference in sensitivity and power handling capacities....

edgewound
10-31-2005, 05:10 PM
Don't MAKE me open these up, now. :no:

We'll leave the actual internal construction for Mr. Widget to discover.... :p

Here's a couple of pics from OCS website of 2407H diaphragm. Does this look like Titanium to you? Not me....unless it's that new, clear titanium.

scott fitlin
10-31-2005, 05:46 PM
It looks more like the BMS in the coax I linked to above. Still, the 0.6" difference in diameters is significant, as is the difference in sensitivity and power handling capacities....I dont know, I do know they look remarkably similar to each other, different mounting assemblies, and the JBL has a differently shaped front, but from the back they look really close. The 0.6" difference in diameter is not to be dismissed either.

BMS rates the 4552ND at 113db1w@1M! What does JBL rate theirs as?

What about the picture of the diaphragm Edgewound put online? It says 2407, is it the diaphragm for the 2407?

Zilch
10-31-2005, 06:08 PM
BMS rates the 4552ND at 113db1w@1M! What does JBL rate theirs as?

What about the picture of the diaphragm Edgewound put online? It says 2407, is it the diaphragm for the 2407?We don't have the specs on 2407, but in one of the systems it's used in, 110 dB.

A call to OCS or JBL Pro tomorrow will clear up the issue of the diaphragm material. I'm only restating what's in the literature. I know nothing but my tests, above.... :p

scott fitlin
10-31-2005, 07:32 PM
We don't have the specs on 2407, but in one of the systems it's used in, 110 dB.

A call to OCS or JBL Pro tomorrow will clear up the issue of the diaphragm material. I'm only restating what's in the literature. I know nothing but my tests, above.... :pAnd I know even less about this tweeter!

But from the side they look quite similar! Its only the front threaded flange and chamfered front that look different to me. The backs look identical.

Mind you, I am not saying anything bad about them, Ive never heard them, and they look interesting enough!

I wonder how they sound, and if they sound better than the slots and bullets?

Did you listen to them? If so, how did you like them? And compare them to the more traditional JBL tweeters, please!

:)

Zilch
10-31-2005, 07:52 PM
Did you listen to them? If so, how did you like them? And compare them to the more traditional JBL tweeters, please!All's I've heard on 'em is pink noise so far. :p

I s'pose, since they're MORE than merely tweeters, I COULD compromise the "NO TWEETERS" rule here and try 'em two-way in the S99 Hotrods. That'll cross them just above 1 kHz.

Gotta reconfigure stuff to make that happen using M552 active and biamping, as all of my crossovers here have compensation in 'em. These don't need it. Maybe I just use a cap for starters.... ;)

edgewound
10-31-2005, 08:13 PM
I dont know, I do know they look remarkably similar to each other, different mounting assemblies, and the JBL has a differently shaped front, but from the back they look really close. The 0.6" difference in diameter is not to be dismissed either.

BMS rates the 4552ND at 113db1w@1M! What does JBL rate theirs as?

What about the picture of the diaphragm Edgewound put online? It says 2407, is it the diaphragm for the 2407?

Yes!!! The picture and the label on this diaphragm don't lie. It's the replacement diaphragm for the JBL 2407H. The JBL Lit is not factual...it's NOT Titanium. I'ts polyester/mylar. I didn't make this picture up, and neither did OCS. I have a burned 2406H diaphragm in my shop...maybe a new one too. It's also polyester/mylar.

scott fitlin
10-31-2005, 08:22 PM
Yes!!! The picture and the label on this diaphragm don't lie. It's the replacement diaphragm for the JBL 2407H. The JBL Lit is not factual...it's NOT Titanium. I'ts polyester/mylar. I didn't make this picture up, and neither did OCS. I have a burned 2406H diaphragm in my shop...maybe a new one too. It's also polyester/mylar.This has my curiosity going.

Poly/Mylar diaphragm and I wonder, if in fact the 2407 does use this material for the diaphragm, how it sounds with todays source material?

It just makes me think of that old EV T-350 or something like that, the one that the klipsch, and a few other guys seem to love, and its diaphragm is not metal, either!

I am beginning to wonder about these 2407,s! Maybe want to try them!

edgewound
10-31-2005, 08:32 PM
This has my curiosity going.

Poly/Mylar diaphragm and I wonder, if in fact the 2407 does use this material for the diaphragm, how it sounds with todays source material?

It just makes me think of that old EV T-350 or something like that, the one that the klipsch, and a few other guys seem to love, and its diaphragm is not metal, either!

I am beginning to wonder about these 2407,s! Maybe want to try them!

The EV ST-350, T-35 is a 1" coil, phenolic diaphragm. The 2406H polyester/Mylar ring radiator is used in the JBL MP412 series speakers. Go to your local JBL Pro dealer and give them a listen.

scott fitlin
10-31-2005, 08:38 PM
The EV ST-350, T-35 is a 1" coil, phenolic diaphragm. The 2406H polyester/Mylar ring radiator is used in the JBL MP412 series speakers. Go to your local JBL Pro dealer and give them a listen.Good idea!

It just occurs to me alot of guys love that EV tweeter, and many say it is easier to listen to than a JBL metal diaphragm!

Same way some guys love the 2482,s for mids!

Ill be in Manhattan Thursday!

Jan Daugaard
11-01-2005, 09:15 AM
http://i6.ebayimg.com/03/i/05/47/d8/18_1.JPG

This is a picture of a 2416H. Does this compression driver have an SS mesh like the 2407H?

edgewound
11-01-2005, 09:25 AM
http://i6.ebayimg.com/03/i/05/47/d8/18_1.JPG

This is a picture of a 2416H. Does this compression driver have an SS mesh like the 2407H?

Yes...it's a screen to keep debris from entering the throat

Rudy Kleimann
11-01-2005, 05:47 PM
http://i6.ebayimg.com/03/i/05/47/d8/18_1.JPG

I saw this ebay auction a couple days ago, and emailed him about it. The auction is still up...:biting:

These are NOT JBL drivers... take a look at the phase plug, No annular slits! Round holes instead. Accepts a JBL or aftermarket clone diaphragm.

I have several JBL MR Series speakers with 2416H drivers, and none of them have "holes" in the phase plug like this pic.

I saw a pair of these same drivers on ebay awhile back, and knew they were not. I cut'n'pasted the pics from that auction into an email to JBL PRO Tech support. The next day, they confirmed with this reply:
Dear Rudy,

Definitely not JBL component. I asked around to see if anybody might know who made this, and it seems to be a Radian, but not absolutely sure.

Hope that helps,

Best Regards,

Alphonso H. Ochoa
JBL Professional
Technical Support


-----Original Message-----
From: Rudy J. Kleimann III
Sent: Thursday, September 08, 2005 3:48 PM
To: Ochoa, Alphonso
Subject: 2416 Drivers: JBL or fakes?

Robh3606
11-01-2005, 07:47 PM
"These are NOT JBL drivers... take a look at the phase plug, No annular slits! Round holes instead. Accepts a JBL or aftermarket clone diaphragm."

Did they check out a 2415??? I also have one of those salt and pepper phase plugs. If it's not a JBL it's a dead ringer. You can't tell one from another asside from differences in the phase plug.

Rob:)

edgewound
11-01-2005, 08:30 PM
http://i6.ebayimg.com/03/i/05/47/d8/18_1.JPG

I saw this ebay auction a couple days ago, and emailed him about it. The auction is still up...:biting:

These are NOT JBL drivers... take a look at the phase plug, No annular slits! Round holes instead. Accepts a JBL or aftermarket clone diaphragm.

I have several JBL MR Series speakers with 2416H drivers, and none of them have "holes" in the phase plug like this pic.

I saw a pair of these same drivers on ebay awhile back, and knew they were not. I cut'n'pasted the pics from that auction into an email to JBL PRO Tech support. The next day, they confirmed with this reply:
Dear Rudy,

Definitely not JBL component. I asked around to see if anybody might know who made this, and it seems to be a Radian, but not absolutely sure.

Hope that helps,

Best Regards,

Alphonso H. Ochoa
JBL Professional
Technical Support


-----Original Message-----
From: Rudy J. Kleimann III
Sent: Thursday, September 08, 2005 3:48 PM
To: Ochoa, Alphonso
Subject: 2416 Drivers: JBL or fakes?


As Rob noted....these are JBL 2415 drivers. They were used in the old MI-series systems from JBL Pro. Some of the youngins at JBL haven't been around long enough to know any better....and all the veterans that built JBL are now long gone.....It's definitely not a Radian. :blink:

louped garouv
11-01-2005, 08:38 PM
how funny....


but maybe the employee's name should be removed?


lest he become the running joke at company retreats.... :o:

heck they may start bringing him all kinds of legacy drivers and request that he ID 'em....

Rudy Kleimann
11-01-2005, 09:24 PM
Well, fellas... don't know what to say:o:

I guess I'll be pullin' diaphragms in my cabs to see what I've REALLY got. Happy to report, I've only replaced diaphragms in JBL compression drivers that were abused by others.

Robh, you are certain? Notice however, the drivers in both cases were advertised as "2416H". Note also the "-1" written on the magnet plate with a sharpie. Maybe 2416H-1? I have seen similar markings on 4" compression drivers too, with "-3", "-1", etc. I recently read somewhere (I think there was a posting on this forum) that these markings, as well as similar markings on the inside of the voice coil formers on diaphragms, were markings for production variations to optimally match drivers and diaphragms. I don't know; I've apparently been wrong once today already.:banghead:

After all the drivers I've seen apart, JBL or others, I've only round holes once before, on a cheap no-name speaker with a 1" diaphragm where the sound wave did not pass through the magnet. ALL the JBL drivers I've had the diaphragm off of used the annular slits.

After finding this site several years ago, and learning of Jim Lansings' fight with Western Electric over rights to the annular slit phase plug design, and Altec going with thr radial slits, I never thought I'd see the day...

As for sympathy towards the JBL Tech support guy over his ignorance and the misinformation provided, should he suffer for his ignorance? :dont-know

edgewound
11-01-2005, 10:36 PM
Well, fellas... don't know what to say:o:

I guess I'll be pullin' diaphragms in my cabs to see what I've REALLY got. Happy to report, I've only replaced diaphragms in JBL compression drivers that were abused by others.

Robh, you are certain? Notice however, the drivers in both cases were advertised as "2416H". Note also the "-1" written on the magnet plate with a sharpie. Maybe 2416H-1? I have seen similar markings on 4" compression drivers too, with "-3", "-1", etc. I recently read somewhere (I think there was a posting on this forum) that these markings, as well as similar markings on the inside of the voice coil formers on diaphragms, were markings for production variations to optimally match drivers and diaphragms. I don't know; I've apparently been wrong once today already.:banghead:

After all the drivers I've seen apart, JBL or others, I've only round holes once before, on a cheap no-name speaker with a 1" diaphragm where the sound wave did not pass through the magnet. ALL the JBL drivers I've had the diaphragm off of used the annular slits.

After finding this site several years ago, and learning of Jim Lansings' fight with Western Electric over rights to the annular slit phase plug design, and Altec going with thr radial slits, I never thought I'd see the day...

As for sympathy towards the JBL Tech support guy over his ignorance and the misinformation provided, should he suffer for his ignorance? :dont-know

FYI....the 2416H-1 diaphragm is a suitable replacement for the 2415H. These drivers are nearly 20 years old so to see a 2415H fitted with a 2416H-1 diaphragm is certainly no surprise. The 2415H has a copper round wire voice coil, the 2416H-1 has an aluminum edgewound voice coil, which is an upgrade fitment. Should Alphonso suffer? Not really....he should just learn from his mistake....I have been corrected here on this forum....and have learned new details about some things, and I've been JBL Authorized Service since 1988....17 going on 18 years. There's over 50 years of products to account for.

Rudy Kleimann
11-02-2005, 03:12 PM
So... you are confirming that the driver pictured with round holes in the phase plug is a JBL 2415 driver?

If so, I learned something new today.

I knew that the 2416 diaphragm was a direct replacement. What I didn't know was that JBL made any compression drivers with this phase plug design :o:

However, the 2 ebay auctions I saw these on still advertised the drivers as 2416H.:bs:

Just goes to show that ebay is the place where, as ebay puts it, "caveat emptor"...

edgewound
11-02-2005, 03:59 PM
So... you are confirming that the driver pictured with round holes in the phase plug is a JBL 2415 driver?

If so, I learned something new today.

I knew that the 2416 diaphragm was a direct replacement. What I didn't know was that JBL made any compression drivers with this phase plug design :o:

However, the 2 ebay auctions I saw these on still advertised the drivers as 2416H.:bs:

Just goes to show that ebay is the place where, as ebay puts it, "caveat emptor"...

Well...with all fairness to eBayers not educated in the internals of the 2415 and 2416 phase plugs....the only place the model number exists on these two variants is on the diaphragm assembly and nowhere else. So if a guy has a 2415H that's been rebuilt with a 2416H/-1 diaphragm, as far as he knows, that's what it is. But yes...as always with eBay "caveat emptor".

Zilch
11-16-2005, 12:32 PM
"Real" 2416H-1:

Zilch
11-16-2005, 12:38 PM
"Are ya STOOPID, Zilchster? 2407H is a TWEETER!"

Yeah, well, lookie here:

http://www.jblproservice.com/pdf/AE%20Series/AM4212,95-WH.pdf

Also, here:

http://www.bmspro.com/products/4540nd.html

WT2 impedance curves on 2342:

1) JBL 2407H
2) BMS 4540nd-8

Rudy Kleimann
11-16-2005, 03:21 PM
"Real" 2416H-1:

Thanks for the pic, Zilchster. That IS what a 2416 driver looks like from the diaphragm/phase plug side.

Like I said, I never knew or would dream that JBL would make a driver with anything but the annular slit phase plug design. I guess it is yet another sign of what Harmon might "require" to make a "competitively priced" driver even 15 or more years ago?

Jan Daugaard
11-17-2005, 01:57 AM
So is JBL buying OEM drivers from BMS, or is it the other way round?

Or are JBL and BMS buying OEM drivers from a third, as yet unnamed company?

Guido
11-17-2005, 03:25 AM
So is JBL buying OEM drivers from BMS, or is it the other way round?

Or are JBL and BMS buying OEM drivers from a third, as yet unnamed company?

Yeah! I could bet this 2407 is a BMS!!! Please Zilch some more pics to be sure.
Anyway it is one of the best BMS Drivers ;)
As for your question Jan I'm almost sure the BMS drivers are made here in Germany.

Guido
11-17-2005, 03:35 AM
Zilch, could you post an RTA plot of 2342 with BMS/2407? with several of your networks please?
Could you also post the same info with the 2344 and or even with the PT Waveguide 100x100 you sent me?

This would be MOST interesting!!!! :bouncy:

Zilch
11-17-2005, 09:36 AM
Zilch, could you post an RTA plot of 2342 with BMS/2407? with several of your networks please? Could you also post the same info with the 2344 and or even with the PT Waveguide 100x100 you sent me?Yup, that's the plan. This weekend, probably.

Preliminary report: 2407 sounds VERY good on 2342 biradial horn, the only combination I've really listened to thus far. Using NL200t3 crossover, I have it padded down about 6 dB more....

edgewound
11-17-2005, 11:45 AM
Zilch,

Have you peeked at the diaphragm yet?

Zilch
11-17-2005, 11:51 AM
Guido: Simple crossover for your horn is here:

http://www.jblproservice.com/pdf/AE%20Series/AM4212,00-WH.pdf


Edge: I'm tempted, of course, but I don't wanna mess until the testing is complete here. ;)

Oldmics
11-17-2005, 12:35 PM
2407 Info

Coil O.D 1.530 (fudge factor)

DCR 5.6

Phase Plug is plastic

Diaphragm material appears to be polymer as it is clear and you can see thru it

Zilch
11-17-2005, 12:50 PM
Polyester or titanium diaphragm?

Phase plug is metal or plastic?

Guido
11-17-2005, 01:47 PM
Definitely a BMS Driver.

Made in USA? Interesting :p

Guido
11-24-2005, 03:31 AM
Yup, that's the plan. This weekend, probably.

Preliminary report: 2407 sounds VERY good on 2342 biradial horn, the only combination I've really listened to thus far. Using NL200t3 crossover, I have it padded down about 6 dB more....

Hi Zilch!

Do you have any news here? I'm toooo curious ;)

Zilch
11-24-2005, 10:53 AM
Sorry, diverted by the arrival of 275nd diaphragms, a different puzzle. :p

More listening results for 2407: Clear, bright, perhaps overly so, independently verified by forum visitors. I may have to use AutoEQ or build up the requisite crossover (link above) to hear how they really should sound.

I'll get back on it, I promise. Also have DDS horns to try with them. Gonna take a little effort, is all.... :thmbsup:

bbrown
11-25-2005, 02:11 PM
A good friend of mine (who unfortunately lives on the other side of the U.S.) has just finished his own design for a cornerhorn, and is using a BMS 4590 (coaxial) for the mid and tweeter. After listening a while and getting over the idea that it's better just because it's different idea, he says the BMS units are really, really good. He doesn't even have it on an optimal horn yet. He is using a P-Audio PH-4525. He would like to try some kind of wood horn or tractrix.

Of course, two drivers at $320 each ought to sound good.

Bruce

Zilch
12-03-2005, 11:14 AM
Do you have any news here? I'm toooo curious ;)
Hang on, Guido.

I'm building AM4212/00 crossovers to run 'em.... :thmbsup:

[Next week, maybe....]

Gotta be steeper slope (24 dB/octave) to play them down at 1.3 kHz successfully....

TimG
12-07-2005, 10:42 AM
I have measurements of the BMS 4540 on the DDS ENG 1-90 horn. It has real extension beyond 20kHz but I wouldn't try to cross it over at 1000Hz. The JBL 2406 is actually closest to the BMS 4552ND ($145) and the 2407 is closest to the BMS 4540ND ($96). BMS will build custom diaphragms for their drivers so the resonance frequency and sensitivity of the BMS and JBL drivers may not be equivalent. I have been using BMS drivers for years and think they sound great. I have used the 4552, 4540 and 4590.

I measured some of these drivers for tomp787 (http://member.php?u=121) and the DDS ENG 1-90 horn with the BMS 4540 would be my top choice for the top end of a 3 way system with a crossover above 1600Hz. If you want to crossover at 900Hz the 4552 would be the more appropriate driver although it does not have the same high frequency extension as the 4540.

I will post some screen captures of measurements tomorrow.

TimG
12-08-2005, 12:41 PM
The first image is the BMS 4540ND on the DDS ENG 1-90 horn and the second is the JBL OASR horn. My sound card and measurement system with a 96kHz sampling rate allow measurement up to 48,000Hz, but my microphone only has a calibration file up to 20,000Hz, so I can't be sure of the response above 20kHz.

Zilch
12-08-2005, 03:17 PM
Just completed 24 dB/octave 1.3 kHz AM4212 crossover to run these (right), here shown on PT-F1010HF waveguide. Comparing LP performance to N3134 (left).

1) The crossover
2) BMS 4540nd on DDS ENG-1-90
3) BMS 4540nd on JBL OASR
4) JBL 2407H on DDS ENG-1-90
5) JBL 2407H on JBL OASR

Zilch deems them, ummm ..., "similar."

[Gotta order up some 2406H's now.... ;) ]

Jan Daugaard
12-09-2005, 08:50 AM
A week ago, I asked BMS through this contact form
http://www.bmspro.com/contact/index.html
if the JBL 2407H is identical to the BMS 4540nd. I didn't get a reply.

Zilch: Is the limited low frequency extension of JBL 2407H and BMS 2540nd due to the horns? What frequency response do these drivers have on other (bigger) horns?

Zilch
12-09-2005, 09:53 AM
Zilch: Is the limited low frequency extension of JBL 2407H and BMS 2540nd due to the horns? What frequency response do these drivers have on other (bigger) horns?In the latest RTA curves above, the crossover is shutting them down. It's essential to do that in order to play them that low.

The "shelf" from 1 kHz to 3 kHz is also apparent in both drivers.

The specs say the useful range begins about 1200 Hz. TimG's measurements confirm response limitations below that. See also:

http://audioheritage.org/vbulletin/showthread.php?p=75158&highlight=standard+mesh#post75158

The diaphragm is only 1.5" diameter. It's not the horns; it's a tweeter....

Zilch
01-02-2006, 03:03 PM
Go here: http://www.uspto.gov/patft/index.html

Hit "Quick Search" at the top left.

Put this number in Term 1: 5,878,148

Make Field 1 "Patent Number."

Hit "Search."

Hit "Images" to see the original, with drawings....

scott fitlin
01-02-2006, 03:28 PM
WHAT do the JBL 2407,s sound like? Compared to traditional JBL slots and bullets?

Zilch
01-02-2006, 03:37 PM
They are "Mellower," though all of the HF response is there. The diaphragms are Mylar, generically speaking, not metal.

2406 sounds the same.

You'll have to wait for others to hear them to confirm this. I don't have slots, only bullets and 2404 mini-butts to compare.

edgewound
01-04-2006, 01:04 PM
Go here: http://www.uspto.gov/patft/index.html

Hit "Quick Search" at the top left.

Put this number in Term 1: 5,878,148

Make Field 1 "Patent Number."

Hit "Search."

Hit "Images" to see the original, with drawings....

Interesting find, Zilch. Looks like maybe JBL is licensing the technology or having them OEM'd by BMS. We'll probably never know definitively....unless BMS is a takeover target of Harman:p ...wouldn't surprise me.

JBL 4645
06-21-2006, 09:49 PM
Zilch

I can see on the RTA some nice HF extension there:) , are you using “wideband pink noise” to test the JBL HF horn?

Zilch
06-21-2006, 09:53 PM
Yes. Behringer RTA sources the pink noise....

JBL 4645
06-25-2006, 11:26 AM
Zilch

I knew it, as it can come in the form of many other sources like CD, sound generator, or the (Behringer), any I like your threads, very clear and detailed.:)

Timothy Bailey
06-27-2006, 10:18 PM
can anyone advise me if it is practical to use a simple first order xover on these @ say 3.5 K

Above a 91db/w unfiltered mid bass Foster 8 incher from the late 1970's. Spherical enclosures!

The amp driving them would be a 'modified Leak Stereo 20' in triode mode IE about 6 watts maximum. It currently has a 1st order R/C input filter -3db @ 175 hz, and I would consider increasing this to ~ 420 hz OR 850, but I don't want to get closer than 2 octaves to 3.5K.

yes I WILL need to level match.

I would also probably be mounting them so the baffle's face neatly meets the lip of the horn ie _/\/\_ okay?

Roughly how much do a pr go for on Ebay?

THEN I'll think about ST's. I am 55 after all ;-)!

TIA from Timbo in Oz

Timothy Bailey
06-27-2006, 10:24 PM
_|/\/\|_ :)

IE the visble part of the bullet tweeter would be the curved in throat and no the straight sides of that throat.

I would hope that this might provide a little support for that part of bandpass immediately above 3.5 k.

As well as minimising early reflections of the mid-bass driver's output.

After all they'll be in spheres ;).

TIA again,

Robh3606
06-28-2006, 04:37 AM
Hello Tim

You may want to drop a post in the Market Place Forum. I am sure you can get them, Mike cadwell has a lot of lenses and may be able to cobble a set together for you. If you can get a pair of 2405's you can change out the phase plug and horn to make 2402's. They are also readilly available on Ebay. I would think you would want the alnico version as they are relatively small and that would make enclosing them a bit easier. Just a thought but you could also continue the flare from the driver into the sphere however I don't know what the loading effects would be.

Rob:)

http://audioheritage.csdco.com/vbulletin/showthread.php?t=11133

Old Pink
02-04-2008, 07:05 AM
You are wrong, the 2407 is a 1" screw-on neodymium ring radiator with a 1.5" voice coil. In fact it is identical to the BMS 4540 but the BMS is rated 8 Ohms while the JBL is rated 16 Ohms. It would be interesting to measure the impedance curves of both types, to see if they really are different. The replacement diaphragm is much cheaper from BMS than from JBL (at least here in Europe).




I don't know anything about the 2407, but after doing a quick search on the JBL Pro site, it appears to be a 1.5" light weight compression driver with unique diaphragm. I would assume it is more closely related to the drivers we tested here:

http://audioheritage.org/vbulletin/showthread.php?t=6050

It does not appear to be a ring radiator.

Widget

Old Pink
02-04-2008, 07:08 AM
The 2407 is identical to the BMS 4540 but the BMS is rated 8 Ohms while the JBL is rated 16 Ohms. It would be interesting to measure the impedance curves of both types, to see if they really are different. The replacement diaphragm is much cheaper from BMS than from JBL (at least here in Europe).



A week ago, I asked BMS through this contact form
http://www.bmspro.com/contact/index.html
if the JBL 2407H is identical to the BMS 4540nd. I didn't get a reply.

Zilch: Is the limited low frequency extension of JBL 2407H and BMS 2540nd due to the horns? What frequency response do these drivers have on other (bigger) horns?

Zilch
02-04-2008, 11:25 AM
2407 is (was) available in both "H" and "J" versions, 8 and 16 Ohms, respectively.

Similarly, BMS4540 is available in either impedance.

There are mechanical differences in BMS vs. JBL implementations of the driver.... :yes:

Old Pink
02-04-2008, 09:22 PM
Yes indeed, you are right. The german BMS distributor (where I got mine) is only stocking the 8 Ohms version. About the mechanical differences I don't know, I never had the opportunity to compare both brands directly. They might result by the fact that JBL is not buying the magnetical structure from the germans; they only buy the plastic part with the diaphragm and voice coil.


2407 is (was) available in both "H" and "J" versions, 8 and 16 Ohms, respectively.

Similarly, BMS4540 is available in either impedance.

There are mechanical differences in BMS vs. JBL implementations of the driver.... :yes:

Old Pink
02-04-2008, 09:45 PM
I dont know, I do know they look remarkably similar to each other, different mounting assemblies, and the JBL has a differently shaped front, but from the back they look really close. The 0.6" difference in diameter is not to be dismissed either.

BMS rates the 4552ND at 113db1w@1M! What does JBL rate theirs as?

What about the picture of the diaphragm Edgewound put online? It says 2407, is it the diaphragm for the 2407?

You cannot compare the 2407 to a 4552ND because the 2407 has a 38mm voice coil and the 4552 has a 44.4mm voice coil. The plastic body is fastened with 4 screws to the magnet assembly with all 38mm types, while all 44.4mm types are fastened with 6 screws.

Old Pink
02-04-2008, 11:54 PM
You cannot compare the 2406 to a 4552ND because the 2406 has a 38mm voice coil and the 4552ND has a 44.4mm voice coil. The plastic body is fastened with 4 screws to the magnet assembly with all 38mm types, while all 44.4mm types are fastened with 6 screws.


I have measurements of the BMS 4540 on the DDS ENG 1-90 horn. It has real extension beyond 20kHz but I wouldn't try to cross it over at 1000Hz. The JBL 2406 is actually closest to the BMS 4552ND ($145) and the 2407 is closest to the BMS 4540ND ($96). BMS will build custom diaphragms for their drivers so the resonance frequency and sensitivity of the BMS and JBL drivers may not be equivalent. I have been using BMS drivers for years and think they sound great. I have used the 4552, 4540 and 4590.

I measured some of these drivers for tomp787 (http://member.php?u=121) and the DDS ENG 1-90 horn with the BMS 4540 would be my top choice for the top end of a 3 way system with a crossover above 1600Hz. If you want to crossover at 900Hz the 4552 would be the more appropriate driver although it does not have the same high frequency extension as the 4540.

I will post some screen captures of measurements tomorrow.

Old Pink
02-05-2008, 12:04 AM
They really do sound great, and at $320 they are a bargain compared to the price of a 2446.


A good friend of mine (who unfortunately lives on the other side of the U.S.) has just finished his own design for a cornerhorn, and is using a BMS 4590 (coaxial) for the mid and tweeter. After listening a while and getting over the idea that it's better just because it's different idea, he says the BMS units are really, really good. He doesn't even have it on an optimal horn yet. He is using a P-Audio PH-4525. He would like to try some kind of wood horn or tractrix.

Of course, two drivers at $320 each ought to sound good.

Bruce

Doctor_Electron
02-06-2008, 08:31 AM
Using the proper crossover/eq the response of the 2404 can be made flat,
with great off axis performance.


Can someone on this forum help me as to how this is done? I have a pair that I used to replace the 035ti's on my 4410s. They seem better, but I know they are performing far from optimum. Also, any help with properly padding them down to make up for their greater efficiency compared with the 035ti's.
BTW, these monitors are used in a near-to-midfield enviornment.
Thanks.

RKLee
02-06-2008, 12:27 PM
can anyone advise me if it is practical to use a simple first order xover on these @ say 3.5 K
.
.I am NOT an expert at this. I am just regurgitating from a JBL brochure, but JBL recommends a xover of 3.5K with a 2nd order xover, ie 12db octave, rather than a 1st order for their 075/2405 tweeter. I would suspect that you could damage 075/2405 because it was not really designed to reproduce sound loudly below 3.5Khz

Rudy Kleimann
02-06-2008, 01:24 PM
After doing a lot of research a couple of years ago here, on the JBL pro website, and anywhere else I could find (including the local JBLPRO service dealer) a couple of things became evident:

All of the old ring radiators used the same magnet structure, except the old ones are AlNiCo and the newer ones (from about 1976 on) were ceramic-ferrite. All four designs use uniquely different phase plugs and corresponding horn throat/bell assemblies. The only other difference was the mounting flange: early ones have a round neck with a circular clamping ring to mount it to the cabinet baffle board, and the later ones had integral mounting flanges that use through-bolts to hold it on the baffle board.

Originally, these diaphragms were made of an alloy JBL called "duralumin" in the old JBL catalogs, but that name has been dropped. Supposedly, this alloy was obtained by recycling the skins of WWII airplanes, and the supply was eventually exhausted. Newer diaphragms are referred as simply "aluminum". Different material or the same? Who knows? Some aftermarket diaphragms are made from Titanium, with uniquely different properties and sound, according to some. Those who have heard them parallel their impressions regarding the sound difference to those about JBL's dome compression drivers equipped with aluminum or Titanium diaphragms.

JBL makes three slightly different diaphragms for these older ring radiators (075/2402 "bullet", 076/2403 "cat-eye", 2404 "baby-butt", and 077/2405 "slot") All are interchangeable, but with slightly different performance and reliability advantages.


All of these ring radiators have the same impedance, about 12 ohms, regardless of the part number having an 8 or a 16 in it as the impedance. The same is true of the drivers- some are marked 8 ohms while others were marked 16 ohms. All the voice coils are the same.

the D8R075 diaphragm material is apparently a little thicker. It's total effective mass is a little higher. Its HF extension is not as good as the others, but it is much more durable. It is the diaphragm of choice for high-level playback for a HP crossover frequency of 2.5-3.5KHz or higher. This is the standard replacement diaphragm for some "-1" variants of the 2404H. This is also noted on some of the exploded diagrams of certain production models that used a 2404H or a 2404H-1 The metal plate in the center and edge of the diaphragm on these are almost always golden in color.

The D8R076 is uniquely for use in the 076/2403 "Cats-eye" tweeter. The center and outer diaphragm plate is almost always blue in color. Not much else I can say about this driver or diaphragm except that they are a cult clssic JBL driver and ungodly expensive -if you can find them to buy.

The D16R2405 is a lighter, thinner diaphragm with better HF response than the D8R075, but are more easily damaged from overexcursion and metal fatigue at high levels when crossed over lower than about 7KHz. Don't know if the inner and outer rings have any coloration other than silver to them at all. They are the replacement diaphragm for most 2404 "baby butt" and 2405 "slot" drivers. Exceptions include some 2404H-1 which used the D8R075. It is good reccomendation to use the D16R2405 in appliocations from 7KHz up, and the D8R075 for applications starting above 3-3.5KHz (as in 2-way systems), with a little UHF rolloff characteristics in the D8R075.

To minimize the risk of damage and get the cleanest response, all of these really should be crossed over at a minimum slope of 12dB/octave. 24dB/oct is really much better in all ways.

Note: be oh-so-careful not to allow the phase plug to twist even a slight amount during tightening down onto the diaphragm and magnet assembly, or the phase plug will put twisted wrinkles in the diaphragm like the tires on a drag car launching from the starting line, resulting in the death of perfectly good -and expensive to replace- diaphragm.

johnaec
02-06-2008, 04:55 PM
...twisted wrinkles in the diaphragm like the tires on a drag car launching from the starting line, resulting in the death of perfectly good -and expensive to replace- diaphragm.Aw, c'mon now - we all know "it makes no difference to the sound...". :p ;) :D

John

subwoof
02-06-2008, 07:56 PM
In about 2 weeks I will do a "mechanical" thread of all the ring radiator mechanical variations over the many years. braclets, horns, throats, clamps, magnets, etc. Even the LE30 variant.

note: the ferrite's were sold beginning in spring 1982. I bought bullets for 2 club installs that year and the january ones were anlico and the april ones were ferrite.

One thing to note - I kept a bag full of bad diaphrams and the color of the outside and inside ring has NEVER been consistent with ANY of the models over the years.

I have silver and gold bullets. I have gold, blue and silver slots. Some with part numbers, some without. Thick leads and thin leads. OEM models and on and on.

With ONE exception. A large group of factory 2403's came in some years ago and the outsides were silver and the insides were blue. Those were the ONLY bi-colored ones I have seen in 30+ years.

I was going to make a hanging mobile of them and title it "blow me" but the wife nixed that idea even though it was in the shop...;(

sub

ps - see avatar.

Rudy Kleimann
02-07-2008, 08:24 AM
Good to see you chime in, subwoof. Looking forward to that thread. Will you PM or email me when you post the thread?

BTW- do you have any of the ring radiators used for ultrasonic railroad crossing, traffic signal controlling, or military variants (or information about them) to post?

I always wondered if the colors were kept consistent as a means of identification of the variants of the diaphragms, apparently not, according to your experience.

I do know that the D8R075 D8R076 and D16R2405 diaphragms are different, and it's not the impedance. It's the thickness of the diaphragm or perhaps the size of the inner support ring, corresponding to the diameter of the phase plug?

subwoof
02-07-2008, 09:40 AM
I will have *some* parts and pix of the tideland signal / and general railway variants.

As far as thickness, I have examples of each - maybe even a 1950 era bullet with the old alloy..? I have yet to see official comment / docs from JBL on this though. Nobody knows anymore. All the old timers have retired.

Maybe I will get them measured at cornell ( next door ) when I find the right contact.

As soon as the borrowed 2403's get here, I will post. Expect odd humor, it might be ale-influenced.

:cheers:

Rudy Kleimann
02-07-2008, 08:11 PM
Actually, a lot of my information came from this site- I did a whole lot of reading researching this about three years ago. I may not remember correctly WHERE I read all this, but I do know it is verifiable fact since I had heard contradictory information from "authority" sources including the local JBL service center and I was determined to find the truth for my own sake. Since I own a couple 075 AlNiCo drivers, a 2404H, a 2405 AlNiCo, and a couple 077/2405H ferrites, I wanted to know details for properly designing a passive crossover and was baffled by the whole impedance controversy surrounding the driver labels and the diaphragm part number nomenclature.

IIRC, Widget posted the impedance details, including his own measurements (with the aid of Zilch) of at least 4 variations and combinations of drivers with 8 or 16 ohm labels and different diaphragm part numbers.The weights of the diaphragms was a common denominator in one of the many threads about ring radiators and diaphragms. In that thread, someone had known part number dia's and weighed them, measured DC resistance, and measured the thickness of the inner and outer mounting rings. I think someone provided a measurement spec for the thickness of the diaphragms... and someone else may have verified that the free air resonance was different between the part numbers. Zilch nailed the "-1" variant of the 2404 in a JBL Cabaret Series cabinet he had at the time that used a D8R075 as the diaphragm, and the exploded diagrams on jblproservice.com listed it as a 2404-1 and a replacement diaphragm part number of D8R075. Other threads here, and some deep reading in JBL tech notes and the JBL PRO Service manual (which either giskard or subwoof emailed me) confirmed this.

Do search for 2-3 year old posts by Widget, Zilch, Steve Gonzales, 4311B (aka Giskard and that oriental princess whatever :D), and myself containing or pertaining to ring radiators, D8R075, and D16R2405.

I'll dig up my notes next time I'm at my own house and can fire up the right PC where I have all these notes saved. In fact, your new thread will be just the impetus I need to do it;)

And now, back to business -Weller 107* over rocks :cheers:

It's been a long day...

Rudy

Mr. Widget
02-07-2008, 09:35 PM
Widget posted the impedance details...Yep... post #51 in this thread.

Quite a while back I was at a friend's house measuring some of his other gear and realized he had a mint collection of these drivers... I already knew from other comparisons and posts by Harvey Gerst and Robert G among others that JBL wasn't really labeling some of their drivers as consistently as we might wish.

Here is the comparison between four original slot tweeters:

http://www.audioheritage.org/vbulletin/showpost.php?p=62922&postcount=51

Widget

Rudy Kleimann
02-07-2008, 10:02 PM
I re-read this thread after my last post... apparently my memory is holding up pretty well (better than my eyes lately:p) Anyway, didn't you and zilch have another thread that also discussed these (and other) drivers? Seems that is where the whole bit about diaphragm weight, thickness, resonant frequency, and F.R. came up, as well as Zilch and the 2404-1 with the D8R075 diaphragm spec'd for it in the Cabaret Series speaker system. Do you recall?

Also worth noting is another thread discussing labels with 8 or 16 ohm impedance ratings on early drivers (woofers in this case) with the same DCR and same recone kits. Harvey Gerst commented that it was (most likely) due to following popular trends at the time and output transformer taps on tube amps (some didn't have 8 ohm taps, only 16 or 32 ohm) of the day- the drivers were actually the same, only the labels changed as 8 ohm drivers became more popular to match up with 8 ohm output taps on the amps of the time.

As you demonstrated, all of the ring radiators tested were closer to a nominal 12 ohms impedance in their operating range, and pretty consistent among the aggregate.

I just put my GF on a plane and am house/dog-sitting at her place tonight. I hope to get by my house tomorrow and open up my JBL notes on these ring radiators to add my documentation to Subwoof's new thread on this. I especially hope to find the JBL documents regarding the Duralumin alloy from WWII aircraft skins and the applications details regarding the D8R075 and D162405 diaphragms to corroborate my story here.

Rudy

Waiting for Spring and warm water...

Allanvh5150
02-07-2008, 11:42 PM
The use of duralumin is interesting. Duralumin is the old name for an alloy of aluminum, or aluminium as we call it, with copper, magnesium and manganese. It is roughly equivalent to the modern spec AA2024 aluminium. The stuff was originally made for airships if my memory serves me correctly. Later on it was used for aircraft. It is a lot harder than normal aluminum, but is more corrosion prone. To improve the corrosion qualities there is a pure coat of aluminum applied to the faces of the sheet. This stuff is used in the aircraft industry today and is commonly called "alclad". Chances are the modern aluminum diaphragms are made of the same stuff.

Allan.

Zilch
02-08-2008, 12:12 AM
Four of us participated in the Widget Works "Ring Radiator Test Fest," as I recall: Infredible, Johnaec, Widget, and me. We all brought stuff, so there was an abundant sample... :yes:

hjames
02-08-2008, 04:07 AM
Four of us participated in the Widget Works "Ring Radiator Test Fest," as I recall: Infredible, Johnaec, Widget, and me. We all brought stuff, so there was an abundant sample... :yes:

Would that be this 8 page long thread?

Horn/Driver Comparision (http://www.audioheritage.org/vbulletin/showthread.php?t=6050&highlight=Ring+Radiator+Test&page=8)


Used the following horns:

1) PT-F1010 - 100° X 100°, 6.5" X 12"
2) PT-H1010, 100° X 100°, 12" square
3) PT-F64, 60° X 40°, 6.5" X 12"
4) SF-95, (Sound Factor), 90° X 50°, 1" thread-on throat, 6.5" X 12"
5) P-Audio PH-230, 100° X 100°, 2342 Clone, 1" bolt-on throat, 9" Square

And used these drivers:

1) 435Be 3" Beryllium Diaphragm 1.5" exit from JBL Consumer
2) 2435HPL 3" Beryllium Diaphragm 1.5" exit
3) 2431 3" Aluminum Diaphragm 1.5" exit
4) 2418 1.75" Titanium Diaphragm 1" exit
5) 2426 1.75" Titanium Diaphragm 1" exit
6) LE85 1.75" Aluminum Diaphragm 1" exit

johnaec
02-08-2008, 06:41 AM
... 4311B (aka Giskard and that oriental princess whatever :D)That would be 4313B .

John

johnaec
02-08-2008, 06:46 AM
Would that be this 8 page long thread?

Horn/Driver Comparision (http://www.audioheritage.org/vbulletin/showthread.php?t=6050&highlight=Ring+Radiator+Test&page=8)Nope. The meeting Zilch mentions was exclusively for testing ring radiators. We *may* have also tested the 035Ti for comparison - I'd have to go back over the thread...

John

Rudy Kleimann
02-08-2008, 07:57 AM
...and controversy:bomb:


That would be 4313B .

John

That would be him. But, what was her name?

I just stick to the name I got in the beginning...:D

Whatever the name, the man has got his data right. Just don't be an idiot and piss 'em off :bash:

and suffer at the hands of the master :flamer:

Rudy Kleimann
02-08-2008, 08:01 AM
[quote=hjames;199893]Would that be this 8 page long thread?

Horn/Driver Comparision


No, but Zilchster has other long threads. All very informative, and shows a lot of fun in his R&D. Though some may find it tiresome or frustrating, I always enjoyed them. Learned from them too.

Zilch
02-08-2008, 04:06 PM
The lovely Miss Orchid jousted with Lancer and another character I will remember next week sometime.... :p

Oldmics
02-08-2008, 09:15 PM
Rudy
Perhaps this is the info that you are seeking?

http://audioheritage.org/vbulletin/showthread.php?t=1462&highlight=diaphragms

Oldmics

Rudy Kleimann
02-08-2008, 10:49 PM
Good job, oldmics! Right on the money. Confirms my memory about subwoof having said some of the things I remember too, although now he has said he doesn't think there is a correlation to diaphragm type and color. I thought you had been a source for some of this, but I've slept (many times) since reading it all, and my PC is unavailable to me at the moment. Bo and Earl K came to mind too, but I couldn't "re member" for sure...

Oldmics, I guess that old moniker of yours "can't re member" is a paradox of its own?;)

Anyway, thanks for chiming in here. I knew I had the data committed to memory right, but couldn't justify it with references. At the time, all I had was two old AlNiCo bullets from (believe it or not) custom stage monitors that belonged to Z*Z*TOP* in the early '70's.

One of these old bullets I have had a twist-wrinkled diaphragm that I still have. If I knew for sure what part number it is, I would slice it, dice it, measure it, and post my findings here now. But how do I know what I have? I do have a dial caliper and know how to use it... maybe it's time to dig it up and do just that-

I think there is still another thread (or two) that is pertinent here. It would've been written prior to August 2005. Anybody else here remember?

grumpy
08-26-2009, 01:11 PM
http://www.audioheritage.org/vbulletin/showpost.php?p=60871&postcount=4

If all goes well, I'll be able to concur with the above measurements in a week
or two :bouncy: ... if not, I'll be looking for some diaphragms.

grumpy
08-28-2009, 06:55 PM
got 'em faster than I expected...

192KHz samplerate, 30KHz calibrated mic, ~1m vert over DUT
2uF in series. If I ever get a mic level calibrator, I'll set units to dbSPL.

Who cares? Performance curves of this model appear rare,
nice to compare measuring systems, and what one might expect
from old/used drivers.

Tracking between 5-10KHz appears reasonable for 30 year old drivers.

Running a 3rd series of tests (1st unit back at test location) confirmed
positioning of test unit was accurate enough for .1dB repeatability
(so I believe the differences between units is real). No attempt was
made to clean up, adjust, or otherwise 'blueprint' the drivers.

Units are within 20, serial #-wise.

Some characteristics from Widget/Zilch plot can be recognized
(appended for ready comparison). I did not repeat the off-axis
measurements.

In-system listening tests will be more interesting, but here's the plots:

grumpy
08-28-2009, 11:32 PM
and an 076 CSD plot for those into such things:

pos
08-29-2009, 01:04 AM
thanks grumpy!

When you're at it... could you mesure horizontal *and* vertical dispersion please? :D

looking at the horn I just cannot understand it how it can have a wider horizontal than vertical dispertion. Is it using pattern flip? (ie loss of directivity control in the shortest horn dimension in its lowest frequency range of use)

John W. drawings :


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8959&stc=1&d=1121438770

toddalin
08-29-2009, 10:41 AM
Ah yes, the classic ~9-10 KHz dip characteristic of the ring radiator and its derivations.
http://audioheritage.org/vbulletin/attachment.php?attachmentid=41483&stc=1&d=1251510534

Zilch
08-29-2009, 10:54 AM
looking at the horn I just cannot understand it how it can have a wider horizontal than vertical dispertion. Is it using pattern flip? (ie loss of directivity control in the shortest horn dimension in its lowest frequency range of use)

It's an elliptical diffraction slot....

pos
08-29-2009, 11:50 AM
but the horn looks big enough to provide pattern control down under 10khz with its profile!...
Say for exemple I put some foam on the face plate of the horn, à la LE25. This would eliminate the diffraction altogether, and leave us with a classic horn, right? The profile of the horn would dictate its directivity down to at least 8khz, don't you think?

grumpy
08-29-2009, 01:20 PM
off-axis measurements? sure, as I have time.

9KHz dip? perhaps, ...much more present on one than the other (in my
limited/old sample of two), but the 4.5KHz response wiggle seems consistent
between at least three 076 units and two measurement system types.
Below the suggested crossover freq at any rate...

I'd -expect- the horizontal pattern to be somewhat diffraction generated as the
transition is so abrupt (something less extreme than the 2405) and the
vertical to be more defined by the horn exit angle... but I'm no horn designer.

If I find some foam to cut up, I might try some "backyard experiments" ;)

pos
08-29-2009, 02:36 PM
:bouncy:

grumpy
09-01-2009, 02:55 PM
some crude, but perhaps illustrative cartoons (program is entertaining,
...after a fashion):

grumpy
09-05-2009, 03:45 PM
just shy of 1m (.86m), and using a much larger cap (13uF) to still protect
drivers from really stupid mistakes but affect measurement less than before (2uF),
stimulus was limited to 1KHz on low-end.

Plotted x-axis is 2.4-24KHz. Happy to take questions/comments/criticism.
(graphs are a bit choppy as I had to manually cut/paste the 30/45 traces)

pos
09-06-2009, 05:37 AM
VERY interesting, thank you grumpy!!

could you try adding a LE25 foam pad on them?
maybe that would suppress that 8khz off axis peak (in both plans)?

here is what Widget did mesure (without 0° normalization) :
http://audioheritage.org/vbulletin/attachment.php?attachmentid=8615&stc=1&d=1119511085

pos
09-06-2009, 05:43 AM
also, here is the L220 directivity measurement (from the brochure...)
It is said to be 90x45 at 12khz
(the 076 starts at 5khz)

grumpy
09-06-2009, 09:21 PM
My measurements don't seem to support the brochure directivity plot,
(at least the 5KHz+, 076-specific portion, understanding that the LE5
will have increasingly less output beyond that frequency)...

...but then I don't claim to have knowledge of the procedure used at JBL,
and I don't recall what threshold (-6dB, -10dB, ?) might have been used
to define angular coverage (neither seem to fit consistently).

I put a mic directly ~1m over the DUT, rotating the DUT in place, keeping
the center of the face directly below the mic (just tipping it, without
recentering, would add an error to the measured angle).

Also, the DUT was not on a baffle ... (Device Under Test). To be a valid
comparison vs. the brochure, one would need to create a similar environment
(baffle size and mounted driver location, and rotate the unit/baffle).

Given all that, I'll see what kind of foam I might have available to test
your hypothesis.

Allanvh5150
09-06-2009, 11:36 PM
The lens on the 220 was on the LE5 was it not?

pos
09-07-2009, 02:01 AM
The lens on the 220 was on the LE5 was it not?
Yes it was. The part in the graph we are interested in is past 6khz

4313B
09-09-2009, 11:17 AM
If I find some foam to cut up, I might try some "backyard experiments" ;)
Happy to take questions/comments/criticism.
Given all that, I'll see what kind of foam I might have available to test
your hypothesis.You could just sell them for vast sums of cash and make them someone else's problem. ;)

Then buy a nice pair of 077/2405's and call it done. :yes:

boputnam
09-09-2009, 12:15 PM
Tracking between 5-10KHz appears reasonable for 30 year old drivers.Yeah - not bad at all for that age. Above that, not so much...

grumpy
09-09-2009, 12:47 PM
OK, ok... I'll just do the one more test for POS-terity :) (I hope mangled
puns translate).

Ducatista47
09-09-2009, 01:20 PM
Just read this thread. In the spirit of just listen to it, I used the slot for years with nothing but listening pleasure. The bullet has given me instant listener fatigue every time. I won't have one in the house.

Of course there might be some suitable application for it. A 25mm soft dome Audex matches up well with my twelve inch full range driver. Perhaps the bullet matches up well with a cat getting its tail stepped on.

Caption of the picture: "Well named. Paladin would have put a bullet through it alright, to put it out of its misery."

Clark

IsakAlexander
10-28-2009, 01:51 PM
Well can any of you experts tell me what this is?
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers040.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers041.jpg
It`s the one 2404 I`ve got, the other two will arrive in 14 days or so. Guess I`ll need new diaphragms for all of them.

grumpy
10-28-2009, 01:58 PM
Thanks for the post... reminded me I was supposed to run a test for POS. :o:

toddalin
10-28-2009, 02:43 PM
Well can any of you experts tell me what this is?
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers040.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers041.jpg
It`s the one 2404 I`ve got, the other two will arrive in 14 days or so. Guess I`ll need new diaphragms for all of them.


Looks to me like a 2404 magnetic assembly and phase plug with a 2402 diaphram that looks aftermarket.

Allanvh5150
10-28-2009, 05:52 PM
Of course there might be some suitable application for it. A 25mm soft dome Audex matches up well with my twelve inch full range driver. Perhaps the bullet matches up well with a cat getting its tail stepped on.


Probably one of the longest produced drivers in history. I am sure the maketing people at JBL can tell you more than a few useful aplications. As for the Audex soft dome, I can give you a few very useful applications for it.

pos
10-29-2009, 04:29 PM
Thanks for the post... reminded me I was supposed to run a test for POS. :o:
:bouncy:

IsakAlexander
01-09-2010, 01:48 AM
Well the bargain I got from ebay turned out to be dissapointing. This is what the diaphragm looked like and this was supposed to be the good one:
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers067.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers068.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers069.jpg
Is it aftermarket or original and if so what type?
Looks like I will have to get 3 new ones :(

yggdrasil
01-09-2010, 06:10 AM
I have seen worse... begin sold as good.

Anyway that looks like a JBL 2405 dia.

The 2404 was sold with both 2402 and 2405 dia's.

juud
03-03-2010, 08:34 AM
Well the bargain I got from ebay turned out to be dissapointing. This is what the diaphragm looked like and this was supposed to be the good one:


The pictures posted by Isak show that there is no guide pin for the diaphragm.
I wonder whether the genuine 077/2405 should has two guide pins? My Frankenstein 2405 from ebay has two guide pins. I suspect that my Ebay's 2405 might be just a 2402 alnoco being assemblied to the 2405 phase plug and horn flare.

Mr. Widget
03-03-2010, 08:49 AM
The pictures posted by Isak show that there is no guide pin for the diaphragm.
I wonder whether the genuine 077/2405 should has two guide pins? My Frankenstein 2405 from ebay has two guide pins. I suspect that my Ebay's 2405 might be just a 2402 alnoco being assemblied to the 2405 phase plug and horn flare.I am not certain, but I believe all of the older ring radiators had guide pins and later they were phased out to make diaphragm installation easier to adjust.


Widget

Rudy Kleimann
06-09-2010, 02:02 PM
Judging by the markings, i'd say it is a real JBL diaphragm and was installed by a JBL Factory Service center, since they almost always hand-write the date of installation on the diaphragm or recone kit. Often, the tech will mark the service center name and the tech's initials, if space permits.

That is a 2405 diaphragm, judging by the width of the moving diaphragm and the width of the inner and outer mounting rings.



Well the bargain I got from ebay turned out to be dissapointing. This is what the diaphragm looked like and this was supposed to be the good one:
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers067.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers068.jpg
http://i132.photobucket.com/albums/q26/IsakAlexander/Speakers069.jpg
Is it aftermarket or original and if so what type?
Looks like I will have to get 3 new ones :(

1audiohack
11-01-2010, 09:53 AM
A 2405 and a 2402 diaphragm. So what is an 076?

1audiohack
11-01-2010, 10:04 AM
The 076 looks to be just a combination of the two.

Robh3606
11-01-2010, 10:20 AM
Can you accurately measure the thickness of the 3 diaphrams?? You can see the compliance in the 2402 I wonder if the 2403 uses the same form as the 2402 but with a thinner diaphram thickness??

Rob:)

Earl K
11-01-2010, 10:28 AM
Hey, some great new info here , many thanks !!!

Btw, nice sectional-slicing of those diaphragms !

Neato set of pics :)

cheers <

grumpy
11-01-2010, 02:16 PM
... the most illuminating 240x physical comparison I've seen to date.
Thanks for taking the time to do the work and post the pics!

1audiohack
11-02-2010, 12:14 AM
With a recently calibrated L.S.Starrett double ball tipped micrometer, all three diaphragms shown in the previous pictures measure right at 0.0020" to 0.0021". No more speculation.

I have to say that pinching an NOS 076 diaphragm between two 0.200" balls almost made me nervous, almost. ;)

pos
11-03-2010, 01:24 AM
Great pictures! Thank you!
Rob, maybe you could post them in the ring radiator transducteur info thread (http://www.audioheritage.org/vbulletin/showthread.php?23869)?
(by the way Rob, thanks a lot for what you posted in that section recently, especially the 2123H data!!)

ivica
11-05-2010, 05:30 AM
The 076 looks to be just a combination of the two.
what a nice work, and lot of info for all JBL "ring radiator" fans.
I have a pair of old 077-alnico drivers. Unfortunately I have to replace diaphragm to one of the driver. Unfortunately only D16R2405 (gold-gold ring dia is possible to get, not blue-blue rings).
Here are responses. I put Beyma CP21F as reference.
First is ORIGINAL 077
Second 077 "motor" with D16R2405
Third Beyma CP21F

ivica
11-05-2010, 06:10 AM
The pictures posted by Isak show that there is no guide pin for the diaphragm.
I wonder whether the genuine 077/2405 should has two guide pins? My Frankenstein 2405 from ebay has two guide pins. I suspect that my Ebay's 2405 might be just a 2402 alnoco being assemblied to the 2405 phase plug and horn flare.

I have a pair of 077, and they have TWO guide-pins

1audiohack
01-05-2011, 09:57 PM
Next up, what's inside the Factory Franken Tweeters, brand new from sealed boxs courtesy of Jeff Keel, the original purchaser/owner. Don't worry Jeff, I'll be gentle!

Steve Schell
01-05-2011, 10:13 PM
Hi folks, I recently found and scanned this 1958 article by George Augspurger. This thread seems like a good place for it.

Rudy Kleimann
01-06-2011, 12:13 AM
Thank you, Steve! Another GEM for the LHS Archives!

Thanks also to LHS member 1audiohack. You have resolved most all the pertinent questions regarding ring radiators IMHO. Grumpy has also been a help too, along with many others including Widget, 4313B (Giskard), Subwoof, Zilch, and many others... a lot of input from many members. that's what makes this site so great!

The only thing that I want to add is that there is a distinct difference between the AlNiCo motors and "Tops" i.e. horn parts, and the Ferrite versions of the same:

1: The AlNiCo magnets have the guide pins, and corresponding holes in the "tops" that bolt on to the magnet assemblies.
2: The AlNiCo magnets are smooth across the top, where the Ferrite magnets have a machined recess of approximately .015"-.017" across the face of the magnet to accept and align the diaphragm.
3: The pole piece is aligned with the outer portion of the top plate in both the AlNiCo AND the ferrite magnets; meaning the diaphragm sits "flat" in either magnet- the diaphragms' inner clamping ring and outer clamping ring sit in the same plane on either magnet: the top of the pole piece is aligned with the diaphragm seating surface on both magnet versions.
4: the "Tops" are machined accordingly to mate with their intended magnets: the AlNiCo magnets mate up with "tops" that have a recess for the diaphragm that is approximately .035" deep, and the ferrite magnets mate up with "tops" that have a diaphragm recess that is approximately .015"-.017" deep.

IIRC, diaphragm clamping rings measure approximately .040" in all cases, I did these measurements last summer and was in regular communication with 1audiohack during the course of our measurements and other sleuthing regarding the distinctions among the various incarnations of JBL Ring Radiators.

I measured this on my AlNiCo 075 and 2402, and compared it to a pair of 2405H as well as the magnet for a 2404H-1 that I have. I used a machinists' straightedge and feeler gauges to measure the diffeneces, and I feel confident in my findings. I believe that 1audiohack would support me on this as a viably accurate method.

That being said, I feel that anyone concerned about "bastardized" combinations of parts could use this method to validate a proper combination...

1audiohack
01-06-2011, 09:07 PM
These just in, whats missing?

1audiohack
01-06-2011, 09:13 PM
I am glad I got all my drivers built last year, from a quality standpoint the future does not look promising from here.:crying:

JeffW
01-06-2011, 09:16 PM
These just in, whats missing?

Polarity dot?

1audiohack
01-06-2011, 09:24 PM
Zactly.

How do you like the voice coil to diaphragm glue job not to mention the gap in the former?

This stuffs not ready for prime time yet here it is. Sad.

4313B
01-07-2011, 10:53 AM
from a quality standpoint the future does not look promising from here.:crying:We've been over this ad nauseum. I get the impression that alot of you guys think JBL was joking when they said it was going to be a real problem moving out of Northridge.

The end of June 2010 was the end of JBL as we know it. Alot of people seem to be in denial which I think is kind of tragic.

toddalin
01-07-2011, 11:18 AM
Will be a real shame when the cheap aftermarket units have better quality (sound???) than the new, more costly OEMs.

1audiohack
01-07-2011, 01:55 PM
I get the impression that alot of you guys think JBL was joking when they said it was going to be a real problem moving out of Northridge.

I didn't, I rebuilt literally every driver and speaker I had and some more to spare when the word came out. I've been through this before with other suppliers.

There has been a lot of speculation, I didn't want to start it all up again but this is proof.

ratitifb
01-07-2011, 02:06 PM
The end of June 2010 was the end of JBL as we know it. :(

Those have done stock don't have to regret :p

Rudy Kleimann
01-08-2011, 01:01 AM
You missed it- how long could N.O.S. last- and who has access to it?

I have a couple of friends I made at JBL in their service and in their Engrg. Tech. Support depts. that I'll have to look up and forward these pics to them. One in particular was critical of the move, yet spoke of the quality increasing quite well down in ole' Mexico.

I'll have to bust his chops' er eyes. with these pics.

Hod forbid if the Chinese outdo us and the Mexicans- I'll forward these pics to Congressmen too.

Remember this in upcoming Elections-

ratitifb
01-08-2011, 05:42 AM
Sorry but i prefer the VC quality from my "old" stock :p

1audiohack
01-08-2011, 11:51 AM
You know there are people in Mexico with fine motor control, in just about every tourist town there is someone who will write you name on a single grain of rice with a pen for a buck. Did they try to find one or two of them to wind coils? Nope. They got the stucco guy that winds them with chicken wire and cement and leaves you a window or two in the process. QC? Obviously non existent. I hope these don't just get looked at and sent back out to someone else, I hope.

This has managed to stay a fairly technically oriented thread so this is the last of this from me, back on to the 2402H-05.

1audiohack
01-08-2011, 09:34 PM
Remember a while ago there was a whole bunch of "nonsense" about attempting to use a D16R2405 diaphragm in a 075 / 2402? Shims, spacers, elastic bands and all?

This is how the JBL factory did it.

The bottom of the phase plug is the same outside diameter, as the standard 075 / 2402, 1.720" and the "shroud" on the bottom of the phase plug is the same depth as all the 075 / 2402, 077 / 2405, 076 and 2404's (both variations) I have measured, 0.040".

What is different is the inner flat area diameter, it is 1.450" rather than the standard 1.400" bullet. Since the outer diameter of the bullet is the same and the inner flat area diameter is different the angle of the shroud is increased to some degree.

Don't mind the dings and burrs huh?

1audiohack
01-08-2011, 09:37 PM
It's a D16R2405 for sure.

1audiohack
01-08-2011, 09:51 PM
Here is a performance comparison.

That's a pretty damn fine performance for a bullet. From a 5kHz to 20kHz average it is 3dB down at 4878Hz and 19,122Hz!

The top chart is magnitude (white) and phase (red) of the 2402-05, the bottom chart is magnitude of the 2402-05 in white and an 075 in yellow. Both charts have zero smoothing applied, all measurments taken at 1 meter on axis.

toddalin
01-09-2011, 11:17 AM
Remember a while ago there was a whole bunch of "nonsense" about attempting to use a D16R2405 diaphragm in a 075 / 2402? Shims, spacers, elastic bands and all?

This is how the JBL factory did it.

The bottom of the phase plug is the same outside diameter, as the standard 075 / 2402, 1.720" and the "shroud" on the bottom of the phase plug is the same depth as all the 075 / 2402, 077 / 2405, 076 and 2404's (both variations) I have measured, 0.040".

What is different is the inner flat area diameter, it is 1.450" rather than the standard 1.400" bullet. Since the outer diameter of the bullet is the same and the inner flat area diameter is different the angle of the shroud is increased to some degree.

Don't mind the dings and burrs huh?


My "shim" was far more elegant, doesn't require butchering the cone, and achieved the same results. My beef with the 075 is not the high end roll off so much as the dip observed at ~9KHz. The dip removes both cymbol "splash" and well as intelligability.

http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Concrete_Rocks/shim1.jpg
http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Concrete_Rocks/Shim2.jpg

The "elastomeric filter" can easily extend the FR of the 2405-diaphragmed 2402 well about 20KHz while further smoothing it out. There is a loss of few dB though.
http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/DSC_0039.jpg
http://www.largescaleonline.com/eimages/lsolpics/Team_Member_Pics/toddalin/Concrete_Rocks/DSC_0037.jpg

1audiohack
01-09-2011, 10:03 PM
The answer to using a D16R2405 diaphragm in the 075 / 2402 is a bullet / phase plug with the correct geometry machined into the bottom. The example shown, nicks dings and all is from a brand new 2402-05. The profile machined into the bottom of the phase plug is that of the 077 / 2405, done at the factory. Hardly butchery in my book besides the obvious lack of care.

Don't get me wrong, I am all for experimentation. For clarification, the nonsense I made reference to was all the serious negativity that came out in that thread. Not to be mean honestly, if you want to use an 075 for an ash tray I couldn't care less. There yours, do with them what you will.

Robh3606
01-10-2011, 06:20 AM
We also had a mystery with 2 different diameter phase plugs in the 2404. Using this as a guide would it be correct to say the the smaller phase plug would go with a 2404-1 using the 2402 diaphram?

Rob:)

toddalin
01-10-2011, 10:10 AM
The example shown, nicks dings and all is from a brand new 2402-05. The profile machined into the bottom of the phase plug is that of the 077 / 2405, done at the factory. Hardly butchery in my book besides the obvious lack of care.



http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=49325&stc=1&d=1294550931
Butchery in my book. :barf:

1audiohack
01-10-2011, 11:02 AM
Hi Rob;

As a guide I would say that is right. However,,,

I have been working to get a good handle on the 2404 / 2404-1 thing. There is a fair amount of uncertainty, I will review my notes tonight and post what I know.

Tod, for clarification, machining the correct geometry in the phase plug for the diaphragm to be used is the right way to go about it. The clown that installed the beat up phase plug pictured as is, is a butcher.

4313B
01-10-2011, 12:05 PM
There is a fair amount of uncertainty, I will review my notes tonight and post what I know.No one wants to pull all the drawings and parts lists so I doubt there will ever be a definitive answer. I know that there are more variants than anyone cares to know about, especially amongst the 075's. That might be why no one wants to pull all the drawings and parts lists...

"Would you want to compile a list of all the ring radiator variants?"

"Oh HELL no!"

:rotfl:

ivica
08-23-2011, 05:17 AM
I have done some measurements all with AlNiCo 'motors' and 077/2405 horn ("slot")
First figure 077 with "Blue-Blue" rings diaphragm
Second figure 077 with "Golden-Golden" rings diaphragms (D16R2405)
Third figure with 2405 (AlNiCo) with "Silver-Silver" rings diaphragm (marked as 2405 from year '84)

It seems to me that nowadays D16R2405 dia is somewhere "in between" older sisters 'blue-blue' and 'silver-silver'(from early 2405-AlNiCo) diaphragms.

Mr. Widget
08-23-2011, 09:06 AM
I have done some measurements all with AlNiCo 'motors' and 077/2405 horn ("slot")
First figure 077 with "Blue-Blue" rings diaphragm
Second figure 077 with "Golden-Golden" rings diaphragms (D16R2405)
Third figure with 2405 (AlNiCo) with "Silver-Silver" rings diaphragm (marked as 2405 from year '84)

It seems to me that nowadays D16R2405 dia is somewhere "in between" older sisters 'blue-blue' and 'silver-silver'(from early 2405-AlNiCo) diaphragms.Did you attempt multiple tests? I imagine you can get that level of change just by taking out and remounting the same diaphragm in the same driver a couple of times.


Widget

grumpy
08-23-2011, 05:15 PM
Indeed. Simply changing the tightness of the phase plug screw can produce a fair amount of FR variability... That, and ensuring the dia is clean and physically distortion free (especially after snugging the screw).

... not to dismiss the measurements taken, but it would be easy to weigh them too heavily for the reasons stated above, -and- that variability of old, used parts, vs new is likely to be large anyway. It would be a large task to obtain enough samples ...

ivica
08-23-2011, 11:44 PM
Did you attempt multiple tests? I imagine you can get that level of change just by taking out and remounting the same diaphragm in the same driver a couple of times.


Widget

Yes, I have done several test with same driver after several days. Of course curves ware not absolutely identical, but "trends" remained, even after 'phase-plug' remounting.
I have one 'silver-silver' diaphragm that has to be replaced (inner part of the membrane is crumpled), so I will make some experiments with the influence of the distance of the phase-plug from the diaphragm (as toddalin did -http://www.audioheritage.org/vbulletin/member.php?230-toddalin).
Changing the sound level in to more then 12dB has almost no influence in the response.

ivica
08-24-2011, 12:08 AM
Indeed. Simply changing the tightness of the phase plug screw can produce a fair amount of FR variability... That, and ensuring the dia is clean and physically distortion free (especially after snugging the screw).

... not to dismiss the measurements taken, but it would be easy to weigh them too heavily for the reasons stated above, -and- that variability of old, used parts, vs new is likely to be large anyway. It would be a large task to obtain enough samples ...

I absolutely agree, but concerning that the trends of the responses are quite different, especially between 'silver-silver' on one side and 'blue-blue' or 'gold-gold' on the other side.
Interestingly almost the same results I have got with JBL 2405/077 "look-alike" slot -ring driver from Beyma CP21F (old model under branded name Mulicell) and DCR4541 on one side and newer model CP21F on the other side.

The older driver (2405,DCR4541 and old CP21F) has relatively flat response up to say 16~18Khz, as 2405 'silver-silver', with some (more or less) peak and sharp "cut-off" after, while 'blue-blue' or 'gold-gold' or new CP21F has wider response, not so flat, but without sharp cut-off at high end.
I believe that there are some technical reason for such behaviors, depending on the aluminum alloy stiffness, thickness, or some minor differences in the membrane shape.

Here we have heard the story about the lady working in JBL who had "repaired" rejected diaphragms for 2405/077 with "blue ball-pointing pen"....so it seems that even small change in the membrane shape has great influence on the driver response.
May be only myth
http://www.audioheritage.org/vbulletin/showthread.php?18519-Ring-Radiator-Production&p=187592&viewfull=1#post187592
http://www.audioheritage.org/vbulletin/showthread.php?18519-Ring-Radiator-Production&p=188524&viewfull=1#post188524

1audiohack
08-24-2011, 07:56 AM
Some part of the pen story is true. I have several D16R2405 diaphragms that have the "rolled rings" in them with the ink color still in them. The proof that it was done during manufacture is evidenced by the fact that the radius and ink is visible under the voice coil lead-ins. I will try to get a good picture of some of them.

Did the measure better? I can't remember.

ivica
08-25-2011, 01:06 AM
Some part of the pen story is true. I have several D16R2405 diaphragms that have the "rolled rings" in them with the ink color still in them. The proof that it was done during manufacture is evidenced by the fact that the radius and ink is visible under the voice coil lead-ins. I will try to get a good picture of some of them.

Did the measure better? I can't remember.

Such photos would be very, very interesting to be seen.
From the fact that the ink and radius is "under" voice coil leads-ins, mean that there were some kind of 'test-bead" for checking the diaphragm operation before fixing outer ring.

ivica
08-29-2011, 05:48 AM
I have one 'silver-silver' diaphragm that has to be replaced (inner part of the membrane is crumpled), so I will make some experiments with the influence of the distance of the phase-plug from the diaphragm (as toddalin did -http://www.audioheritage.org/vbulletin/member.php?230-toddalin).


Here are measured responses what has been done with 2405 (AlNiCo) with 'silver-silver' diaphragm, that has some amount of mechanical
imperfection in inner part of the membrane. Response presented on second figure.
I believe that that is the main reason why this driver does have almost "ruler-flat" response
as the second one with "silver-silver' diaphragm whose FR was presented earlier
( http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&p=319031&viewfull=1#post319031 ).
I have realized that in this special case there is some amount of "hole' around 9kHz, with some frequency "boost" around 11~12kHz, with some kind of hole and peak about 18kHz
I have used "paper shims thick about 0.1mm", that I have put under "central phase plug" only.
Generally my conclusion would be:
-no shims or only one shim has almost no influence (may be flatten 11~12 kHz boost)
-adding any shims more would reduce efficiency by some amount
-2 shims would reduce mentioned HF peak which is about 18kHz
-up to 4 shims would reduce HF peak, but HF response would remain over 16.5kHz
-8 shims would reduce efficiency much more (about 3dB) and would reduce HF response more, but total response would come flatten almost up to 16kHz.

toddalin
08-29-2011, 11:08 AM
I have realized that in this special case there is some amount of "hole' around 9kHz, with some frequency "boost" around 11~12kHz, with some kind of hole and peak about 18kHz.


I found that the 9kHz hole is probably a product of the ring radiator design and it shows in the bullets (the worst), butt cheeks (about as bad as the bullets with 2402 phragms but better with 2405 phragms, and slots (the best).

Even JBL recognizes this and the crossovers are designed with this dip in mind to augment this area. That's why they have the 1 mfd/0.18 mH choke/1.5 mfd. The combination of the two caps creates a peak in this area.

ivica
08-30-2011, 12:03 AM
I found that the 9kHz hole is probably a product of the ring radiator design and it shows in the bullets (the worst), butt cheeks (about as bad as the bullets with 2402 phragms but better with 2405 phragms, and slots (the best).

Even JBL recognizes this and the crossovers are designed with this dip in mind to augment this area. That's why they have the 1 mfd/0.18 mH choke/1.5 mfd. The combination of the two caps creates a peak in this area.

Yes, your words about JBL crossover networks really explain the reason for presence of some overshoot in UHF network section (alone), and some time this 'overshoot' has to be lowered by putting the resistor 'in parallel' with the choke (N3145), especially if planed other ring radiator to be used instead of 240x (such as Beyma CP21F for example, or some "good" sample of 2405)

maxwedge
03-01-2012, 01:26 PM
Need a few more stickies here.;)

Steve Schell
12-17-2012, 12:56 AM
Here's an interesting aside to this essential old thread. My Cogent speaker partner Rich and I have recently made what we think are significant improvements to our field coil compression drivers, and are considering jump-starting our company Cogent Loudspeakers again after several years of minimal activity. We are keeping mum about the nature of these improvements, at least until we get a little further along. I will hint that they are due to the little-known contributions of a genius engineer from RCA's past. The newly modified drivers have brought new life to our systems, and we are once again stoked and in hot pursuit of the most accurate sound possible. One side effect of our driver mods is reduced top end in our DS-1428 mid/high frequency driver, so I tried adding a pair of JBL 075 tweeters crossed in with simple 2 mfd. oil caps to cover the top couple of octaves. We have actually been experimenting with various horn tweeters in our systems in recent months, with some degree of success, after years of attempting to extract adequate top octave performance from our 1428 mid driver.

Anyway, I have come away with new found respect for the 075! As a way to help evaluate our driver progress, I fetched an oldie but goodie 1970s Tama drum set from the closet and set it up in my living room, right in front of the big folded 15Hz. flare horn sub. I set up my usual recording rig in the position of my listening chair and made some recordings while flailing away on the drum kit ( I am a former mediocre drummer from elementary and first year high school). The recording rig is a pair of English Reslo ribbon mics in a classic Blumlein array, feeding a line stage hi fi tube preamp pressed into service as a mic pre with gain wide open, feeding an Alesis Masterlink hard disc recorder set at 24 bit, 96 kHz. On the recordings I speak as well as bang on the drums and cymbals, and the spoken word is a good way of establishing the correct in-room playback level. Jeez, talk about source material, the drum kit is the sh**, both in terms of frequency and dynamic range.

The fun part of this experiment is that the playback sounds remarkably similar to the live sound! The 075s play an important part in this as they handle the 5kHz. and up range remarkably well. Big snare, tom tom, kickdrum and cymbal hits sound very much (I'd say 90% +) like the real thing in a direct comparison to live drumkit debauchery. I had thought that we were still miles away from verbatim reproduction (as JBL used to call it), but now I think that we may occasionally come closer than that. The 075s hold up their end of the frequency range extremely well, and are the only tweeters on hand that keep up with the Cogent drivers in sensitivity. I'm really impressed by them at the moment, and will have to study this thread and others here to come up to speed on these fine JBL ring radiator drivers that I really don't know much about.

Any LH dudes or dudettes in so. CA that would like to have a listen to my "live vs. reproduced" demo are welcome to contact me at (562)421-5145.

Predrag Dukic
12-20-2012, 12:31 AM
Could You say something about DS-1428.. I am interested in TS parameters: Mmd, BL Le etc... Could You reveal at least that?

ivica
12-20-2012, 02:34 AM
Here's an interesting aside to this essential old thread. My Cogent speaker partner Rich and I have recently made what we think are significant improvements to our field coil compression drivers, and are considering jump-starting our company Cogent Loudspeakers again after several years of minimal activity. We are keeping mum about the nature of these improvements, at least until we get a little further along. I will hint that they are due to the little-known contributions of a genius engineer from RCA's past. The newly modified drivers have brought new life to our systems, and we are once again stoked and in hot pursuit of the most accurate sound possible. One side effect of our driver mods is reduced top end in our DS-1428 mid/high frequency driver, so I tried adding a pair of JBL 075 tweeters crossed in with simple 2 mfd. oil caps to cover the top couple of octaves. We have actually been experimenting with various horn tweeters in our systems in recent months, with some degree of success, after years of attempting to extract adequate top octave performance from our 1428 mid driver.......



Does your improvements being applicable to the 'ordinary' -"DOME-type Diaphragm" (ferrite, alnico, Neodymium) permanent magnet (such as JBL 244x~245x) drivers ?

http://www.oswaldsmillaudio.com/steve.html


Regards
Ivica

pos
11-20-2013, 01:37 PM
Here we have heard the story about the lady working in JBL who had "repaired" rejected diaphragms for 2405/077 with "blue ball-pointing pen"....so it seems that even small change in the membrane shape has great influence on the driver response.
May be only myth
http://www.audioheritage.org/vbulletin/showthread.php?18519-Ring-Radiator-Production&p=187592&viewfull=1#post187592
http://www.audioheritage.org/vbulletin/showthread.php?18519-Ring-Radiator-Production&p=188524&viewfull=1#post188524

Some part of the pen story is true. I have several D16R2405 diaphragms that have the "rolled rings" in them with the ink color still in them. The proof that it was done during manufacture is evidenced by the fact that the radius and ink is visible under the voice coil lead-ins. I will try to get a good picture of some of them.

Did the measure better? I can't remember.

This was confirmed by David Smith (http://www.audioheritage.org/html/perspectives/smith.htm) here: http://www.diyaudio.com/forums/multi-way/246196-jbl-2404-dsp-has-someone-done.html#post3710662

Those curves are from a really good one. The ring radiators vary all over the place. The 3 peaks that make up the response can be quite nasty. They did get somewhat better when they trained a lady to go around the perimeter with a ball point pen to crease the edge just inside the suspension point. (I kid you not. You can usually see the blue ink line.)

4313B
11-20-2013, 01:43 PM
:rotfl:

Yeah, G.T. once said that the various model numbers didn't matter so much as finding a matched pair. In other words, if you had to run an 075 on the left channel and an 077 on the right channel to end up with a matched pair then so be it. I love his sense of humor.

:rotfl:

Very cool that David is so active on that forum. Great guy! :yes:

How does he feel about the whole DSP thing? I noticed that he mentioned it in that post. I consider the M2 a great advancement of his 4430/4435 design.

pos
11-20-2013, 04:59 PM
He is not that much into constant directivity these days it seems. He preaches for smooth power response, but no necessarily flat. I think he tends to prefer slowly increasing directivity with frequency, similar to what multiway direct radiator speakers do.

Here is what he has to say about the M2 waveguide, compared to the 2344:
My sense is that the JBL designers today are much less obsessed with polar curves and achieve a reasonable overall compromise in their horn designs. Less good in the polars but better in frequency response and with a flaster flare to hold the distortion down.

Probably the smartest approach.

Their current trend is to forego the diffraction slot and simply do a blend of fairly straight side walls and end flaring. As mentioned a few posts back, this will give less perfect polars but better frequency response. They are quite far from classic exponential so I would like to see some raw horn curves to see what the low end looks like.

Odd
11-21-2013, 01:23 AM
:rotfl:

Yeah, G.T. once said that the various model numbers didn't matter so much as finding a matched pair. In other words, if you had to run an 075 on the left channel and an 077 on the right channel to end up with a matched pair then so be it. I love his sense of humor.

:rotfl:

Very cool that David is so active on that forum. Great guy! :yes:

How does he feel about the whole DSP thing? I noticed that he mentioned it in that post. I consider the M2 a great advancement of his 4430/4435 design.


I bought 6 units 2405 and found two that matched well!

4313B
11-21-2013, 08:50 AM
I bought 6 units 2405 and found two that matched well!Excellent! :)

grumpy
11-21-2013, 09:05 AM
Excellent!

... if you're a "the glass is 1/3 -full-" kind of person ;)

toddalin
11-21-2013, 10:32 AM
When I last obtained three 2405s (for L/C/R), two had consecutive serial numbers and the other was maybe a few hundred away. Logic would put the two consecutive numbers in the L/R and the other in the C. But the one that was a few hundred away was much closer in response to one of the consecutive numbered one, and the other consecutive numbered unit actually had the best response (smoothest and most extended). So the one with the best response (but most different) became the center channel.

Dr.db
03-31-2014, 06:13 AM
BTW; how do 2405 and 2403 compare in terms of efficiency :confused:

2405 has 105db/1w, but how about the cat-eye...???

ratitifb
03-31-2014, 08:05 AM
BTW; how do 2405 and 2403 compare in terms of efficiency :confused:

2405 has 105db/1w, but how about the cat-eye...???:hmm: seems to be specified at the same value @1m

from http://www.audio-heritage.jp/JBL/unit/2403h.html

2405H FR
61792

2403H FR
61793

pos
03-31-2014, 10:33 AM
Here are my own measurements, including 30° off axis horizontal and vertical (this is where the 2403 shines).
It is quite similar to the measurements published by ratitifb (where did you find those?), especially when you consider unit to unit differences (even when new). According to these measurements, -10dB would be around 110dB/1w/1m...

2405H:
61794

2403:
61795

Dr.db
04-01-2014, 12:57 AM
Thanks a lot....

Efficiency seems to be at 105db for both of them, right ?

ivica
04-01-2014, 01:52 AM
Here are my own measurements, including 30° off axis horizontal and vertical (this is where the 2403 shines).
It is quite similar to the measurements published by ratitifb (where did you find those?), especially when you consider unit to unit differences (even when new). According to these measurements, -10dB would be around 110dB/1w/1m...



Hi pos,

I am not sure whether 2405 or 2403 is better for home listening as too large vertical dispersion of 2403 (relative to 2405) can introduce comb effect owing to the reflection from the floor or ceiling.

Regards
Ivica

pos
04-01-2014, 12:23 PM
Hi Ivica

Some directivity is probably a good thing, but I think the 2405 is way to extreem in the vertical plan: -15dB at 30° is way to much for neafiled or midfiled listening, and it already bears its own comb filtering and lobing on its own...
Beside that, what horn would match that directivity at the crossover point, and still maintain a >90° directivity in the horizontal plan?...

The 2404 is probably not directive enough, and I think the 2403 does hit a sweat stop, and will be a perfect match for most horns, crossosed over anywhere from 5kHz up...

ivica
04-02-2014, 03:15 AM
Hi Ivica

Some directivity is probably a good thing, but I think the 2405 is way to extreem in the vertical plan: -15dB at 30° is way to much for near-filed or mid-filed listening, and it already bears its own comb filtering and lobing on its own...
Beside that, what horn would match that directivity at the crossover point, and still maintain a >90° directivity in the horizontal plan?...

The 2404 is probably not directive enough, and I think the 2403 does hit a sweat stop, and will be a perfect match for most horns, crossed over anywhere from 5kHz up...

Hi POS,

if +/- 15 deg vertical dispersion angle is acceptable, and if 2405/077 is located around 90cm from the floor , and about 250cm distance from the listening place that would correspond to 90cm+/-67cm (=23cm/157cm) height region, what seems to me quite acceptable for home listening region (in the vertical plane).
If about +/- 40 degs horizontal dispersion (around 9kHz) is the figure what can be expected from 2405, then I would not expect to have a large (if any) 2405 incompatibilities with the most of the CD or bi-radial horns.
I have 2311horn + 2308 lenses "coupled with" 2405 driver, (crossover around 9kHz) and I can not hear any anomalies moving either left-right or sitting-standing while listening.
While measuring (because of the drivers/horn geometry as VHF driver is about 20cm behind UHF) a large comb-filter effect can be seen, but I would expect the same would happen with the 2403/076 either.

Regards
Ivica

audiomagnate
04-06-2014, 10:52 AM
I think the dispersion characteristics of the 2405 are close to ideal. My L300's put out a lovely image in a three person wide area of the listening couch, and great balanced sound throughout the room, especially in the area behind the couch. I also hear nothing strange happening when I stand up. This is NOT the case with any planars I've tried of course, or even conventional systems with dome tweeters, like my Cremonas.

ivica
04-07-2014, 01:50 AM
I think the dispersion characteristics of the 2405 are close to ideal. My L300's put out a lovely image in a three person wide area of the listening couch, and great balanced sound throughout the room, especially in the area behind the couch. I also hear nothing strange happening when I stand up. This is NOT the case with any planars I've tried of course, or even conventional systems with dome tweeters, like my Cremonas.

Hi audiomagnate,

I can not agree more with your words, and want to say that 2307/2312/2311 with 2308 Lenses help too.

Some useful reading may be:

http://libinst.com/PublicArticles/Setup of WG Speakers.pdf


Regards
Ivica

martin_wu99
04-07-2014, 08:16 AM
Here are my own measurements, including 30° off axis horizontal and vertical (this is where the 2403 shines).
It is quite similar to the measurements published by ratitifb (where did you find those?), especially when you consider unit to unit differences (even when new). According to these measurements, -10dB would be around 110dB/1w/1m...

2405H:
61794

2403:
61795
Pos,excellent job:applaud:

audiomagnate
04-07-2014, 08:36 AM
Hi audiomagnate,

I can not agree more with your words, and want to say that 2307/2312/2311 with 2308 Lenses help too.

Some useful reading may be:

http://libinst.com/PublicArticles/Setup of WG Speakers.pdf


Regards
Ivica

Broken link.

hjames
04-07-2014, 08:41 AM
Broken link.

The link works if you copy paste the whole link WITH THE SPACES EMBEDDED

http://libinst.com/PublicArticles/Setup of WG Speakers.pdf (http://libinst.com/PublicArticles/Setup of WG Speakers.pdf)

martin_wu99
04-07-2014, 09:00 AM
Hi Ivica

Some directivity is probably a good thing, but I think the 2405 is way to extreem in the vertical plan: -15dB at 30° is way to much for neafiled or midfiled listening, and it already bears its own comb filtering and lobing on its own...
Beside that, what horn would match that directivity at the crossover point, and still maintain a >90° directivity in the horizontal plan?...

The 2404 is probably not directive enough, and I think the 2403 does hit a sweat stop, and will be a perfect match for most horns, crossosed over anywhere from 5kHz up...
I like the sound of 2404 in my 4628B.
But why is only 2405(077) in old 43xx series and not 2403(076)?2403(076) can only be seen in some big Westlake speakers:blink:

ivica
04-08-2014, 02:02 AM
I like the sound of 2404 in my 4628B. But why is only 2405(077) in old 43xx series and not 2403(076)?2403(076) can only be seen in some big Westlake speakers:blink:
I believe that a "complex marketing reasons" is the main "issue" as 2405 has wider ( about 2kHz ~ 3kHz, but over 18kHz) frequency range then 2403 (as can be seen from the measurements).
Almost the same as the usage of 045 driver in DD66000 box.
045 is working "almost from 19kHz and up" ?????

regards
ivica

martin_wu99
04-08-2014, 11:11 PM
I believe that a "complex marketing reasons" is the main "issue" as 2405 has wider ( about 2kHz ~ 3kHz, but over 18kHz) frequency range then 2403 (as can be seen from the measurements).
Almost the same as the usage of 045 driver in DD66000 box.
045 is working "almost from 19kHz and up" ?????

regards
ivica
You said 2405 has wider frequency range than 2403,means it is more hi-fi than 2403,but 2404 also has wider range as 2405.does 2403 cost really more expensively than 2405?since so many people think 2403 is better than 2405,why JBL only use 2405 in old 43XX series,there must be another reason,who knows?:dont-know:

best regards
Martin

ivica
04-09-2014, 07:10 AM
You said 2405 has wider frequency range than 2403,means it is more hi-fi than 2403,but 2404 also has wider range as 2405.does 2403 cost really more expensively than 2405?since so many people think 2403 is better than 2405,why JBL only use 2405 in old 43XX series,there must be another reason,who knows?:dont-know:

best regards
Martin

Hi Martin,

As I have remembered 2405 is the only driver (from 240x family: 2402, 2403, 2404) reproducing over 20kHz .

regards
ivica

martin_wu99
04-10-2014, 12:00 AM
Hi Martin,

As I have remembered 2405 is the only driver (from 240x family: 2402, 2403, 2404) reproducing over 20kHz .

regards
ivica
Hi ivica,
I think that is not the truth,
2404H:Frequency Response ( ± 3 dB): 4 kHz to 19 kHz,Usable Frequency Range ( - 10 dB): 3 kHz to 21.5 kHz
2405H:Frequency Response ( + 3 dB): 7 kHz to 20 kHz,Frequency Range ( - 10 dB): 6.5 kHz to 21.5 kHz
2402H:Frequency Response (±3 dB): 3 kHz to 15 kHz,Frequency Range (–10 dB): 2.5 kHz to 15 kHz
2403:105 dB SPL 5khz-21.5kHz @ 1watt 1 meter, freq range 5kHz-21kHz
It seems only 2402 can not reach 20khz:blink:
regards
Martin

ivica
04-10-2014, 01:39 AM
Hi ivica,
I think that is not the truth,
2404H:Frequency Response ( ± 3 dB): 4 kHz to 19 kHz,Usable Frequency Range ( - 10 dB): 3 kHz to 21.5 kHz
2405H:Frequency Response ( + 3 dB): 7 kHz to 20 kHz,Frequency Range ( - 10 dB): 6.5 kHz to 21.5 kHz
2402H:Frequency Response (±3 dB): 3 kHz to 15 kHz,Frequency Range (–10 dB): 2.5 kHz to 15 kHz
2403:105 dB SPL 5khz-21.5kHz @ 1watt 1 meter, freq range 5kHz-21kHz
It seems only 2402 can not reach 20khz:blink:
regards
Martin

Hi Martin,

May be MY understanding about the upper frequency response of the driver is not correct, but looking at
the curves 2405 vs 2403
http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&p=360551&viewfull=1#post360551

on MY OPINION 2405 has higher FR then 2403, for the others You haven given us.

regards
ivica

tomee
04-10-2014, 06:00 AM
Hi ivica,
I think that is not the truth,
2404H:Frequency Response ( ± 3 dB): 4 kHz to 19 kHz,Usable Frequency Range ( - 10 dB): 3 kHz to 21.5 kHz
2405H:Frequency Response ( + 3 dB): 7 kHz to 20 kHz,Frequency Range ( - 10 dB): 6.5 kHz to 21.5 kHz
2402H:Frequency Response (±3 dB): 3 kHz to 15 kHz,Frequency Range (–10 dB): 2.5 kHz to 15 kHz
2403:105 dB SPL 5khz-21.5kHz @ 1watt 1 meter, freq range 5kHz-21kHz
It seems only 2402 can not reach 20khz:blink:
regards
Martin

for marketing purposes (because the market is fixated on 20kHz as some 'magic' number to reach), it appears that the 2405 wins.

martin_wu99
04-10-2014, 09:58 PM
Hi Martin,

May be MY understanding about the upper frequency response of the driver is not correct, but looking at
the curves 2405 vs 2403
http://www.audioheritage.org/vbulletin/showthread.php?6368-Ring-Radiator-Comparisons&p=360551&viewfull=1#post360551

on MY OPINION 2405 has higher FR then 2403, for the others You haven given us.

regards
ivica
Hi Ivica

Back to the previous question,why dose Westlake only choose 2403 to being used in his most expensive high-end speakers SM-1 and HR-7,but not 2405?it is beyond my ken:crying:

regards
martin

martin_wu99
04-10-2014, 10:10 PM
for marketing purposes (because the market is fixated on 20kHz as some 'magic' number to reach), it appears that the 2405 wins.
Maybe JBL engineers themseve did not realize how good 2403 is untill Westlake reveal it.

ratitifb
04-11-2014, 02:17 AM
Maybe JBL engineers themseve did not realize how good 2403 is untill Westlake reveal it.i doubt of that but certainly it's true for a specific enclosure design for a specific use like Westlake recommends in studio environment...

ivica
04-11-2014, 05:50 AM
Hi Ivica

Back to the previous question,why dose Westlake only choose 2403 to being used in his most expensive high-end speakers SM-1 and HR-7,but not 2405?it is beyond my ken:crying:

regards
martin

Hi Martin,

I have no exact answers, but
1. 2403 (owing to the ellipse-look horn mouth) is more attractive to be seen then "edgy" 2405 (slot)
2. May be they prefer 2403 wider vertical dispersion (up to 16kHz) as we have seen from the measurements
3. May be they not pay their their attention on FR over 16kHz (as just a few listeners can be aware of)

regards
ivica

ivica
04-11-2014, 06:15 AM
Maybe JBL engineers themseve did not realize how good 2403 is untill Westlake reveal it.

May be, but not to forget some names that have been there at that time in JBL ( Mr. G.T, Mr. Gary Margulius,.....).

Reagrds
ivica

Mr. Widget
04-11-2014, 08:40 AM
Back to the previous question,why dose Westlake only choose 2403 to being used in his most expensive high-end speakers SM-1 and HR-7,but not 2405?it is beyond my ken:crying: I would bet Westlake has used the 2403 primarily due to it's rarity. Who else in the world has used them since the '80s... also, I don't think even Westlake has them any more. A few years back Ken Pachkowsky was scouring the used/NOS market trying to find a pair for them.

I'm going to say it is marketing driven not engineering/performance driven.


Widget

pos
04-11-2014, 10:51 AM
IMHO the 2403 is far more usable than the 2405 (lower crossover point, much more controlled off axis behavior, etc.)
The on axis response of the 2405 is indeed more linear and a bit more extended (but really, how cares about extension above 17kHz ??), but if you look at unit to unit matching all these consideration become moot anyway...
Point is: on axis response can be equalized, beamwidth cannot...

Dr.db
05-18-2014, 09:17 AM
Most people recommend the 2405 over the 2402 due to its wider freq. range....

But is their a lot happening above 15khz in reality ?
And is the usual individual aged above 30 still capable of hearing these frequencies anyway!?

toddalin
05-18-2014, 11:12 AM
Most people recommend the 2405 over the 2402 due to its wider freq. range....

But is their a lot happening above 15khz in reality ?
And is the usual individual aged above 30 still capable of hearing these frequencies anyway!?
No, I don't agree. Most people recommend the 2405 over the 2402 due to the much more linear response at ~9kHz (even if they don't know it). Most of us have no problem with ~9 kHz and the drop out in the 2402 is substantial compared to the 2405. The ear really picks up on this on ride cymbols, etc., but also in vocal intelligibility.