2435HPL vs. 435Be

[jim henderson]

Does anyone know the differences between the 2435HPL and 435Be? They're both 3" beryllium diaphragms. Are they both 1.5" exit? The cases are obviously different. The 435Be are apparently Aquaplas coated.

[Mr. Widget]

They both use the same motor and diaphragm, but the civilian version has a larger rear cavity as well as those pretty fins.

I don't know if the 2435HPL has aquaplas or not. They both use fero fluid and take the same 1.5" horns.

Widget

[subwoof]

Hey there - I have a pair of the 2435HPL's - no aquaplas, no pretty fins but are 1.5" and damn light...

sub

[Mr. Widget]

The 435Be is a shockingly light driver as well. Probably only a tad heavier due to the larger cast aluminum rear chamber.

Subwoof,

How do they sound? What horns are you using with them?

Widget

[subwoof]

Right now they are stuck on the new 2313's I made ( see other post ) and they are much smoother than the 2421B they replaced.

Below is a picture.....

However I am awaiting the 2332's.....gonna retrofit the baffles on the 4345's to allow those ( and the original ) horns to be used.

When I get them I will try a number of driver / horn combinations and post my observations.

I have never been a big fan of having short wavelength audio splattered by plastic ( or metal ) plates to create width. This also allows me to make shallow depth grills to minimize the overall cabinet depth.

sub

[Guido]

Hi Sub!

Can you provide us with response measurements of the driver? I heard at the music fair in frankfurt that the 2435 needs a strong HF EQ as the Mids are soooo much louder.

Thanks!

[johnaec]

Any idea how the 2435HPL compares with the 2430H? Is the only difference the aluminum diaphragm in the 2430H? I'm on the verge of getting a pair of 2430H and the 2332 horns...(gathering all the parts for a custom HT system...).

John

[subwoof]

hey there... I have no current way to measure this driver - I have retired ( sold ) all the old analog test gear and will be jumping into the newer DSP based measurement setup when I get a settlement this summer.

I don't even have a functional RTA at the moment...:(

Every time I restore one a customer begs to buy it and *poof* it's gone...

sub

[jim henderson]

I'm finally getting my test equipment together. Here's some preliminary measurements:

http://www.pogeyrealestate.com/personal/measurements.htm

[johnaec]

So any impressions on what the 2435HPL with the 2332 horn sounds like yet?

John

[jim henderson]

So far it appears to be rather harsh, but that's probably a result of my test components:

Source: computer with M Audio 2496 card
Ashly 4.24G crossover/EQ
QSC 502 for the 1400ND
McCormack DNA 0.5 for the 2435

My good source equipment is in a rack in another room, so I haven't tried it yet.

The pulse artifact concerns me, so I'd like to solve that mystery first.

[speakerdave]

Originally posted by jim henderson
So far it appears to be rather harsh . . .

The pulse artifact concerns me, so I'd like to solve that mystery first.
Is it possible the pulse artifact is stored energy in the diaphragm surround or back chamber? What about changing the damping to see if that has an effect? (That is, if you dare mess with a diaphragm that would cost $700+ to replace . . . I don't know as I would.)

I wonder if anyone at JBL would talk about it.

[speakerdave]

Widget says, "the civilian version has a larger rear cavity."

I wonder if the reason is to do something about this echo you've found.

[Alex Lancaster]

Hi:

It wouln´t be too hard to make a spacer to increase the back chamber volume.

[jim henderson]

The "echo" comes about 1.4 ms after the pulse response. Does that seem to be too long to be stored energy in the diaphragm surround or back chamber?

I'll continue to mix and match components and environments this weekend.

Has anyone taken a 2435 apart? I've never taken a compression driver apart. Would I have to realign the diaphragm?

I wonder what the back chamber volume difference is and why JBL added volume to the 435Be? Is there damping material in the 435Be back chamber?

[speakerdave]

Originally posted by jim henderson
The "echo" comes about 1.4 ms after the pulse response. Does that seem to be too long to be stored energy in the diaphragm surround or back chamber?

I don't know. Too long for the diaphragm surround, probably. Figured on the back of an envelop that's enough time for sound to travel a little less than a half-meter, so "echo" may not have been a good term to use. I was really thinking that the energy might be being "stored" in something that is flexing and then springing back the way a cabinet panel does. Ever since Bo and Widget posted those photos of the fins on the 435 I've wondered about them. If they are for heat dissipatiion why would they be needed more on a domestic driver than on one used in the big concert arrays? Could they be there to give the back chamber total rigidity? Is it possible the relatively plain back cover of the 2435 has a ring to it? If that's what is happening wrapping the back of the driver in a thick layer of modelling clay should reduce that artifact you are seeing.

Do we in fact know that the internal dimensions of the back chamber are different? Is there damping material in there similar to what is in other drivers? If the answer to both of these questions is yes, is there MORE damping material in the 435?

Jim, Widget, I totally understand your hesitancy to remove the back cover of those drivers. Maybe we can get this information from JBL.

Subwoof has had his apart. Subwoof, what's it like in there?

I wonder what the chances are of the back cover of the 435 showing up on the miscellaneous parts list.

Is it possible that "echo" or "artifact" is not big enough to worry about?

Also, I see a blip in the 035 trace with approximately the same delay. Could the source be elsewhere in the setup?

Lots of questions.

David

[jim henderson]

Subwoof,

Can I safely remove the back shell without affecting the diaphragm alignment?

[subwoof]

no problem...just be sure to align the input terminals when re-assembling. To save space, the old "lead wire" method is replaced by ittybitty spade leads.

sub

BTW - I am selling off the entire "I'll get around to building these someday" collection of components. I have all the parts to build a set of DMS-1 and 4345's....and about 50KW of crown power...

need stuff????

[jim henderson]

I removed the back shell to see what's inside and was surprised to find that the diaphragm is attached to the back shell and not the body as I expected. The 3" dome occupies most of the tiny back chamber leaving very little volume behind the diaphragm.

[johnaec]

Jim - did you ever come to any conclusions about the anomolous pulse respone you were seeing with the 2435/2232 combination, or is that what you're tracking down with opening the drivers?

John

[jim henderson]

I'm trying to track down the cause of the 1.4 ms pulse. I planned to open the back shell and measure the pulse while it was open, but I can't do that because the diaphragm is in the back shell and the magnet is in the body.

The next challenge will be EQ. They get very efficient in the upper vocal range and that needs to be tamed somehow.

[Mr. Widget]

Greg Timbers at JBL initially suggested we use the 2435HPLs for the Project May. He told us that to better the performance we would want to increase the rear chamber. We never pursued this as shortly there after JBL donated the 435Be drivers. I have no idea what the improvement would be.

Are your drivers ferro fluid cooled?

Widget

[Don McRitchie]

Actually, Greg's original suggestion was to use 2430's since these aluminum diaphragm drivers were much less costly than either the 2435 or 435Be. However, I believe that his comment regarding the rear chamber was equally valid for both pro drivers. However, as with Mr. Widget, I'm not sure what the difference would be. Greg did mention that the AL versions really needed to be aquaplased for hi-fi use to smooth out an otherwise harshness in the midrange.

[speakerdave]

Originally posted by Mr. Widget
Greg Timbers at JBL initially suggested we use the 2435HPLs for the Project May. He told us that to better the performance we would want to increase the rear chamber. We never pursued this as shortly there after JBL donated the 435Be drivers. I have no idea what the improvement would be.
Widget

I'm going to guess this has to do with the lower crossover frequency. In the arrays I'm aware of using the 2435 it is used above the neodymium 8" midrange. What do you all think?

[johnaec]

Originally posted by Don McRitchie
Actually, Greg's original suggestion was to use 2430's since these aluminum diaphragm drivers were much less costly than either the 2435 or 435Be.It's good to hear Greg holds the 2430 as good enough for this application, since those are the versions I'm primarily interested in. I'd really like to hear someone's impression and/or measurement of those with the 2332 horns. Actually, I think what got me started on those in the first place was someone else's thread here in the past about their positive impression incorporating that combination in a custom system...

BTW, I'd be crossing them over above the 2012H midrange, (realizing EQ will probably be necessary, barring a good passive crossover design).

John

[Mr. Widget]

speakerdave,

What is your x-over frequency? The Project May will be around 800Hz.

I would assume a larger rear cavity will lower the driver's resonance allowing a lower x-over point. I would assume your x-over point is above 800Hz, so that might be the thinking.

Widget

[speakerdave]

In the VT4889 array the 2435 is used above the neodymium 8" midrange. Crossover frequencies are not given in the spec sheet I've seen. I would think it to be much higher than either the 650 or 800 the 435Be cuts in at in the K2 or Synthesis speakers. What do you all think?

[speakerdave]

Originally posted by Mr. Widget
speakerdave,
What is your x-over frequency?
Widget

I'm not there yet, but for some reason I've had a hunch I would need to add a driver between the 1400nd and the 2435. Right now I'm dreamin' 2250, but they're $500 each.

David

[speakerdave]

Also, in the array the 2435 is the tweeter and is spec-ed out to 16k. Some of that high end would be lost with the larger chamber. If I use it stock I may not need a supertweeter and could put that savings toward the midrange. (heh heh). Only thing is, it's not a K2 anymore; it's a hybrid three-way that JBL never bothered to build, and that gives me the willies. Also, I would be completely without a starting point on crossover design--not even frequency response curves for the drivers. Without a genius-level crossover it would be a mere collection of very expensive drivers. Just thinking out loud here. The chances of my making it sound more accurate than the LSR32 are practically nil.

David

[speakerdave]

Here's a picture of the neodymium 8" midrange. I've put it up so everyone can see what I'm talking about.

[johnaec]

Don't they use the 2250 in a front "slot" loaded enclosure? I wonder how it'll sound as a plain direct dadiator? 'Probably real good, at least in its range...

John

[speakerdave]

Hey, John,

Yes, that's right, and I'm not aware of another application. That and the 2435 are really very raw material. It's a challenging project, but with some prospects for significant success. The 2250 might actually be the key element.

I don't have much in the way of test equipment, but I do have a VTVM so I suppose I could begin by ascertaining the resonance point of the 2435.

David

[subwoof]

I'm thinking of customizing a pair of 2102H by replacing the surround with foam and relaxing the spider...but that 8" 2250J looks nice...

Or maybe getting the 10" 2251J as used in the HLA..?

2405
2332 / 2435HPL
2012H*
1400Nd
1400Nd

enclosure of soild ash and similar to the 250ti in appearance.

has preliminary spousal acceptance factor ( at least it's not the 4345 "refridgerator" look...:) but cost for those mids....ouch

sub

[jim henderson]

See http://www.dovecanyontech.com/personal/jbl2435-2.htm

Sandwiching the 2332/2435HPL between a 2012H and a 2405 might work perfectly. The upper crossover point should probably be near 9 KHz. What crossover freq would you use for the 2012H?

[subwoof]

Well a urei 525 will be used in stereo 3 way so it will be passive to the 2405's at around 10K.

The 525 will have seperated ( cocentric ) freq controls to allow under / overlapping and independant freq counter switches. The coupling caps will be bypassed, the transformers ( and totum pole ckts ) will be bypassed and the usual powersupply stuff....

sub

[jim henderson]

subwoof says the 2435 diaphram should *stay* in the driver when the cap is removed. My 2435 diaphram stayed in the cap. How should the diaphram be affixed?

[tomp787]

Hello,

Is the aquaplas 2430 mentioned above available from JBL?

Thanks,
Tom

[mikebake]

Originally posted by subwoof
Well a urei 525 will be used in stereo 3 way so it will be passive to the 2405's at around 10K.

The 525 will have seperated ( cocentric ) freq controls to allow under / overlapping and independant freq counter switches. The coupling caps will be bypassed, the transformers ( and totum pole ckts ) will be bypassed and the usual powersupply stuff....

sub

Mike;
Let me know when/if you end up with a realized design; maybe something for me to copy if you like it.
MBB

[Don McRitchie]

Originally posted by tomp787
Hello,

Is the aquaplas 2430 mentioned above available from JBL?

Thanks,
Tom


Not to my knowledge. JBL had offered to do this as custom work just for Project May until they offered us the 435Be driver instead.

[speakerdave]

Originally posted by subwoof
I'm thinking of customizing a pair of 2102H by replacing the surround with foam and relaxing the spider...but that 8" 2250J looks nice...

Or maybe getting the 10" 2251J as used in the HLA..?

2405
2332 / 2435HPL
2012H*
1400Nd
1400Nd


sub

Subwoof,

Looks as though we've been thinking along similar lines.
Couple of questions:
Why the 2332 instead of the 2313?
How are you using the 2 1400nd?

David

[speakerdave]

I think the JBL speaker closest to what we're talking about here is the 4348.

Interesting to note that they used the 2251J (10" neodymium) and not the 2250J (8" neodymium).

Can anyone identify the midhorn used in that speaker? Is it available as a part over here? It looks like it might be just the horn for the 2435.

They used the 435AL driver. Does anyone know the differences/similarities of this driver and the 435Be or the 2435 or 2430? Functionally, I mean?

David

[subwoof]

OK - what's the 2313?? I am not near my library due to home remodeling projects...

I have some 2352's if size isn't an issue..:)

The 2332 is a nice size ( real close to the 2308 footprint on a baffle ) and is black... 90 degrees and minimum vert dispersion.

Haven't decided on the 1400 chamber issue but look at this thread:

http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=646&highlight=1400

I have (9) urei 65-5 amplifier modules to power all this with so I *can* eq a bit...

sub

[speakerdave]

subwoof: "OK - what's the 2313??"

Isn't that what you called your shortened 2307?

David

[subwoof]

oh yeah.....it's been a REAL crazy 2 months here....those are STILL sitting on a shef awaiting installation....:0)

And I never have been real crazy about using plastic / metal plates to obstruct the sound either...

mike

[speakerdave]

Well, I personally think the "2313" is a gem of an idea.

I understand about the remodelling projects. My speaker plans are months behind because of a big plumbing project that needed to be done. And to some people a grown man messing with speakers looks like a person in need of some suggestions.


David

[jim henderson]

And to some people a grown man messing with speakers looks like a person in need of some suggestions.

Uh, I think you just described all of us ;)

[subwoof]

Yeah, well the wife was somewhat lukewarm on man-eating size speakers until I mentioned my hobby *could* of been greasy car engines or bass boats....

:)
:cheers:
:cheers:

[speakerdave]

A guy could put some of these together. I happened on a fellow once in San Francisco who ended up showing me his collection of '50's Packards. His garage speakers were Bozak Concert Grands.

And you could build a wooden bass boat.

David

[subwoof]

OK giskard - a quick question....is it possible to get the larger backshell to upgrade my 2435's to the 435Be?

I will be playing in that crossover region.

paint, decals, etc not needed and I can deal with the wiring.

sub

[speakerdave]

Originally posted by Giskard
The 2435 is the Pro version of the 435Be. The 2435 is "good" down to ~ 1 kHz and is designed to work well with the loaded 8", 10", and 12" midbass transducers. The 435Be has the larger can in order to extend response down to ~ 650 Hz. It also has a fancy exterior for Consumer appeal. High frequency roll-off is such that passive EQ isn't very successful. Parametric EQ is the way to go with these compression drivers.

I'm going to try an interpretation here. With the digital controller used for the arrays the response out to 16.5k can be brought up to work with the level of the 5k-9.5k region (in Jim's response curve), but if using passive EQ to stifle the stronger region to match it to the highs it takes too much out of the response.

So . . . . does that leave open the possibility of using the 2435 as a midrange from say 1.6k to about 9k or 10k using passive EQ to bring down the 5k-9k region and horn support to bring up the response in the low thousands ???

What horn you ask? I dunno. Jim's response curve was taken with the 2332, and the support in the low thousands does not seem adequate. I'm going to guess that in the arrays JBL is cutting the 2435 in up around 2500-3k at least or is applying active EQ in the low thousands. Either way the use of the 2435 seems to be getting thornier.

The horn used in the 4348 would help, I think. The midhorn in that speaker is cut in at 1k. Some additional compensation probably would be needed to account for the differences between the 2435 and the 435 back chambers.
The 4348 also shows the 2251 could be used instead of the 2250, at a savings of more than $300/pair. Low crossover in that speaker is 300Hz, better with a ten inch, and leaves a wide lattitude for woofer choice.

Haven't even thought about the supertweeter yet.

When does an apparently modest statement actually veil the most incredible presumption? When it says: "The chances of my making (this speaker) sound more accurate than the LSR32 are practically nil." Sorry about that.

David

[speakerdave]

This might be one possible answer--the horn from the S4800. It is used to cut the 435Al in at 900. Looks quite compact and short.

339360-002 HORN $250 (from Giskard)

on this thread:
http://audioheritage.csdco.com/vbulletin/showthread.php?s=&threadid=2106&highlight=045ti

David

[jim henderson]

I'd love to test one of those horns out. Maybe somebody could lend me one (secured by a deposit of course). Is there any documentation on it, besides the S4800 docs? (I already know the answer ;) )

[speakerdave]

Looks like this horn is used in the S4800, S5800 and the SK2-1000. All of these are products available on the consumer side in the US, so at SOME POINT it, as well as the 45ti supertweeter that fits into it should be available from Harman. This horn will accomodate a 1K hz crossover into the midhorn (the frequency Giskard was told the 2435 was good down to), and so, with perhaps some additional compensation, this problem may be solved. The three speakers that use this horn with the 435Al may also provide a starting point for the crossover design.

Incidentally on that thread you will see that the 435Al with the oft-mentioned larger back chamber is available for about $367. It would be nice, as you said, subwoof, if the back chamber were available as a part on its own.

David

[speakerdave]

Does anyone know of any experimentation with the 2435 on a bi radial like the 2344? Do those horns give more support in the lower frequencies than the FFBR like the 2332? I won't mention any names right here, but I know where I can get a 100 X 100 1000 Hz horn like that with a 1.5" entry diameter. Here's Jim's response curve with the 2435 on the 2332 (you'll need to scroll down to the third chart):
http://www.dovecanyontech.com/personal/jbl2435-2.htm
And here is the response curve of the 2425 mounted on a 2344.
http://www.lansingheritage.org/images/jbl/specs/pro-comp/2344/page3.jpg
The curves seem to complement one another somewhat.

Does anyone know if the tube-mounted curves of the 2425 and the 2435 differ? If so how so?

David

[herve M]

Originally posted by subwoof
oh yeah.....it's been a REAL crazy 2 months here....those are STILL sitting on a shef awaiting installation....:0)

And I never have been real crazy about using plastic / metal plates to obstruct the sound either...

mike

Hello Mike, have you use 2313 ? Disappointed by 2332 /2430, I would to use 2307 modified.
Herve M

[PSz.]

Howdy all,

I just got my 2435hpl set and couldn't resist popping off the back covers. It looks like JBL gave us a convenient way to "enlarge the rear cavity." IF you are willing, you can remove the label on the back of the drivers where it says 2435hpl... underneath you will find a pre-threaded hole. If you leave this hole open or put a small air filter on it (like those used on gas powered radio control cars), then you will have increased the apparent volume of the rear cavity. I would call this aperiodic damping. This should lower Fs and distortion as long as you drive it at reasonably sane levels. Please let me know what you think! :cool:

Thanks,
PSz.

[speakerdave]

For comparison purposes in trying to figure out horn loading and equalization for the 2435HPL can anyone steer us toward a plane wave tube response graph for the 2425 or other legacy driver?

Thanks

I have found some additional information about the 2435H:

1) The wave guide used in the arrays is primarily designed to simulate a line source for the high frequencies. This means, I would say, that although there may also be response tailoring in the wave guide, the driver is not limited to use with this horn and could be used with other loading.

2) I have found a plane wave tube response graph of the driver. It is in a Doug Button paper available here:
http://www.jblpro.com/vertec1/doug%20button%20258%20final%20rev%20c.pdf

3) The graph shows that in the plane wave tube response at 10k is down only about 5 dB referred to 1k. I think that is much better than the legacy drivers with Al and Ti diaphragms. I think for hi fi use this is still a midrange driver, but . . .

4) Unlike mere mortal metal diaphragms which go into break-up modes around 3 or 4K, the Be phragm does this at 14-15k. I think this means the driver should be smoother sounding and require less upper frequency compensation. (This may explain the response curve and the harshness Jim hears with the driver on the 2332 horn). This frequency response combined with the superlative transient response provided by its light-weight diaphragm should make this a very, very nice midrange driver.

5) In the 4889 array this driver is crossed over at about 1k. The array is strictly used with digital system controllers which can provided extensive response tailoring. These controllers and the software can be obtained, but the software would not be applicable to non-array use of the drivers. To me this is not a problem. I think these drivers and the midrange 8" can be used in other ways.

6) The curve provided had been smoothed with 1/3 octave EQ.

I think crossover and filter design for this driver will need to be done based on measurement and may not be possible (as suggested above by Giskard's source) using passive filtering alone unless the most serious anomolies are at one end of the frequency range and can therefore be avoided by changing the crossover point(s). I also think that having the plane wave tube responses of other drivers would give us a starting point in seeing what horns would be most suitable and what compensation would be needed.

Also, my comments in an earlier post in this thread guessing at what EQing the 2435H may need are all wet and should be disregarded.

David

[PSz.]

If you assume similarities with the 435be/horn from the K2S9800, then quite a bit can be gleaned from the passive x/o in that speaker. You can find the schematic at http://manuals.harman.com/JBL/HOM/Do%20it%20yourself%20guides/K2S9800-9800SE%20Troubleshooting%20Guide.pdf

PSz.

[speakerdave]

OK. What is all them little doo hickies?

[PSz.]

Them little doo hickies constitute JBL's best try at how to cross the 435be at 800 and 10kHz along with their try at smoothing the overall response, Oh yeah, it also includes their 9 volt battery biasing for the network. :cool:

Speakerdave wrote:
I think crossover and filter design for this driver will need to be done based on measurement...

I figure if you measure then you can tailor the response to your special combination of room, horn, driver etc. instead of settling for a cookie cutter design.

Speakerdave wrote:
For comparison purposes in trying to figure out horn loading and equalization for the 2435HPL can anyone steer us toward a plane wave tube response graph for the 2425 or other legacy driver?

They are in the driver data sheets. Start here:
http://www.jblpro.com/pages/components/componts.htm

PSz.

[speakerdave]

Originally posted by PSz.

They are in the driver data sheets. Start here.

No. That's not what I'm looking for. Those graphs are made using various horns. I'm looking for tests done with the standard 2" plane wave tube damped at the end with a wedge of fiberglass. Those tests can be used as standard of comparison between drivers. Tests done with horns cannot.

David

[speakerdave]

Originally posted by PSz.
Them little doo hickies constitute JBL's best try at how to cross the 435be at 800 and 10kHz along with their try at smoothing the overall response, Oh yeah, it also includes their 9 volt battery biasing for the network.


I guess that means you don't really understand it either. Right?

Anyway, thanks for the lead on the schematic. It may come in handy.

David

[PSz.]

Scroll down a little further on the data sheet. I have verified that the plane wave terminated tube curves are present on the 2447 and the 2451, but they are using a 1.5 inch tube. (which is probably most appropriate since those drivers are 1.5 inch exit like the 2435);)

PSz.

[speakerdave]

Originally posted by PSz.
Scroll down a little further on the data sheet.

OK. Thanks. That is helpful. I think what I'm seeing means that this driver should be used on a constant directivity horn. It will require somewhat less lift in the higher frequencies than other drivers.

David

[PSz.]

I plan to use mine in a two way configuration with a 15 inch driver taking care of the mid/bottom. I will be using something along the lines of a small edgarhorn or sierra brooks tractrix horn to load the 2435s.

see:
http://www.sierra-brooks.com
and
http://www.edgarhorn.com

PSz.

[speakerdave]

What crossover frequency are you contemplating?

[PSz.]

Somewhere between 800 and 1300 Hz. L/R 24db per octave active filter. In order to pull off the 800 Hz I think that the rear chamber on the driver must be enlarged. This is what my first post on this thread dealt with.

:)
PSz.

[PSz.]

Howdy,
I am wondering if anyone has had luck getting the large finned backshells from the 435be to convert their 2435s. I tried calling JBLPro and JBL Consumer directly but without a part number I didn't get too far. Subwoof have you had any luck?

Much Thanks,
PSz.