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View Full Version : Replacing 2231 in 4333 with 2235



speakerdave
03-25-2006, 12:55 PM
Even though JBL has long since discontinued the 2231 kit and offered the 2235 as a replacement, I think it may not be ideal in some situations. I'm just trying some 2235's in my 4333's. The bass is clearly tighter with lower distortion, but the midrange is just as clearly not as good.

What the reasons are is a question. These are used 2235's that have not been tested in any way, but they look clean and seller maintains they have been lightly used. Another unknown variable is the condition of the Alnico magnets in my 2231's, although I know their history and am quite certain they have not been abused.

If you compare the published frequency response curves of the 2231 and the 2235 you will see significant differences in the range from about 600 Hz upward. The 2235 has a pretty sharp rise followed by a ragged decline, whereas the 2231 has a more gradual rise extending farther into the midrange and a smooth decline. At least, this is how the two are pictured.

With an 800 Hz crossover point those differences would be audible, I believe. Perhaps what is more important may be the measures that have been taken in designing the crossover for the 2231 which might suppress that midrange plateau. That would be exactly the wrong thing to do with the 2235. The upper range of the 2235 may not match up well with a crossover designed for the 2231, so the sound in the crossover region is being dominated by the horn. On the other hand, a crossover like the 3135 for the 4430 may have been tweaked to deal with the upper range of the 2235, but I wouldn't know how.

I would say a 2231 or 136 in a four-way, or a three-way with a lower crossover point could be reconed with the 2235 kit without hesitation. If, however, you have a 2231 in the 4333 or similar three way, and your 2231 cones are ok, and you are considering whether to refoam or recone, I would definitely suggest using the unsanctioned after market foams and keeping the original cones, based on my anecdotal experience. If your cones are gone, of course, there is no other option but to recone.

David

Edit: On reconsidering, it might have been better to put this thread in general discussion. I put it here, because I really wanted to elicit comment from anyone who might have technical information bearing on this issue.

4313B
03-25-2006, 01:05 PM
I would asbolutely use the 2235H kit. If you think the 2235H doesn't sound good in an L300 or 4333 then tweak the network.

speakerdave
03-25-2006, 01:24 PM
Yeah. I really wish I hadn't done this. I was enjoying these speakers a great deal. Now I don't think I would ever be happy with the 2231 bass, knowing the 2235 is better. On the other hand, I can't listen to them this way.

I'm using a zero feedback tube preamp now, and I noticed a little bloom in the bass with that change. It really wasn't objectionable, but I thought the 2235 might restore some of the overall tightness in the bass. They did. I'm so into the midrange of this preamp, though, that I'm not ready to give it up.

Rather than start digging around in the crossover of a classic, I think the next step for me is to biamp, using a crossover with selectable slopes for the low pass, but things are clearly pointing in the direction of a four-way. For biamping I really want a cone midrange driven by tubes.

David

Robh3606
03-25-2006, 03:45 PM
Hello Dave

If you thinking along those lines you might want to drop in the 10" to a 4344. Only uses the 2235 up to 300Hz or so and the 2122 is killer. It helps the 1' driver as well with crossover shifted up to 1.2K Sorry your not happy with the new kits.

Rob:)

Mr. Widget
03-25-2006, 04:46 PM
Unfortunately dropping a pair of 2122s into an existing pair of 4333s isn't exactly possible... and Dave's 4333s are in very nice shape... that said, maybe a pair of DIY 4344s are in order???

I must agree that pushing the 1" driver up a few hertz is a welcomed relief and the added sonic texture gained by adding the midbass driver is also quite an additional benefit.


Widget

speakerdave
03-25-2006, 05:47 PM
Well, I have a pair of gray 2122 frames waiting here, maybe it's time to have them reconed and do a mock-up of the top three drivers on top of these biwireable 4333's.

David

boputnam
03-25-2006, 06:06 PM
This thread is going in just the right direction... :applaud:

Mr. Widget
03-25-2006, 06:20 PM
Well, I have a pair of gray 2122 frames waiting here....Do it, do it, do it... think Animal House here.:D


Widget

Chas
03-25-2006, 11:07 PM
My 2 cents worth here: I swapped AlNiCo 2231's that had been re-coned as 2235's in my 2 channel system operating at the time from 100 - 800 Hz for factory 2235H's that I swiped from my 4430's.

Major change for the better, over here :yes:

The 4430's now sport old 2231's with 2235 cones......but they are on HT duty, so who cares?:p

speakerdave
03-26-2006, 01:31 PM
My 2 cents worth here: I swapped AlNiCo 2231's that had been re-coned as 2235's in my 2 channel system operating at the time from 100 - 800 Hz for factory 2235H's that I swiped from my 4430's.

Major change for the better, over here :yes:

The 4430's now sport old 2231's with 2235 cones......but they are on HT duty, so who cares?:p

All useful information. It's not that I don't think the 2235 has the range. It's just that I think the crossover/filter requirements for the 2235 and the 2231 are different.

David

speakerdave
03-26-2006, 01:32 PM
Do it, do it, do it... think Animal House here.
I'm still working in this allusion. I may need to watch the movie again.

David

toddalin
03-26-2006, 07:42 PM
I'm still working in this allusion. I may need to watch the movie again.

David

Instead of do it, do it, think toga, toga.;)

speakerdave
03-26-2006, 08:01 PM
Instead of do it, do it, think toga, toga.;)
Ah. OK. The idea being, there's a whole crowd repeating the chant. I hear it, I can hear it now.

herve M
03-27-2006, 03:45 AM
All useful information. It's not that I don't think the 2235 has the range. It's just that I think the crossover/filter requirements for the 2235 and the 2231 are different.

David

Yes, the 2235 in 4333a is very different. Disapointed !! :D bad medium frequency. the 2231 is better choice .
Hervé

4313B
03-27-2006, 07:30 AM
If you compare the published frequency response curves of the 2231 and the 2235 you will see significant differences in the range from about 600 Hz upward. The 2235 has a pretty sharp rise followed by a ragged decline, whereas the 2231 has a more gradual rise extending farther into the midrange and a smooth decline. At least, this is how the two are pictured.Please post both for a visual. I don't feel like hunting them down and doing it myself.

speakerdave
03-27-2006, 11:01 PM
Here they are:

johnaec
03-28-2006, 09:00 AM
Note that JBL used to smooth out all their earlier published response curves. The 2235 curve literally doesn't deviate more than + or - 2db from the 2231 curve in the high end. I just think they may have decided to forego smoothing by the time the published the 2235 curves...

John

4313B
03-28-2006, 09:44 AM
Yes, the 2235 in 4333a is very different.I've never heard that before.
the 2231 is better choiceGood luck with that then. Those kits have been gone for decades. You must be listening to 2231's with shot spiders and degaussed motors. I suppose some people could grow accustomed to such.

Note that JBL used to smooth out all their earlier published response curves.I thought perhaps someone had run across the real 2231 curve. I'll see if I can find one and then I'll post both curves.

Rolf
03-28-2006, 01:44 PM
Giskard. You are as always a perfectionist.:applaud:

4313B
03-28-2006, 02:41 PM
Giskard. You are as always a perfectionist.:applaud:Yeah, I should be shot and put out of my misery. Life is too messy and imperfect. Totally overated. Ick! :barf:

Well, except for the girls gone wild part. That part is pretty damn fun to witness. :rotfl:

Rolf
03-28-2006, 03:48 PM
Yeah, I should be shot and put out of my misery.


Well, I do not think so. Even you have your good sides.:p



Life is too messy and imperfect. Totally overated. Ick! :barf:


What would you do without it? (life).:blink:



Well, except for the girls gone wild part. That part is pretty damn fun to witness. :rotfl:

Make me believe it!:)

speakerdave
03-28-2006, 09:16 PM
Note that JBL used to smooth out all their earlier published response curves. The 2235 curve literally doesn't deviate more than + or - 2db from the 2231 curve in the high end. I just think they may have decided to forego smoothing by the time the published the 2235 curves...
Yeah, no doubt those published curves are irrelevant. There's probably something wrong with my setup. I'll try and look into it and see I if I can figure something out, and I'll get back to you all if I come up with something.

Regards,

David

Tom Loizeaux
03-29-2006, 06:30 AM
Yeah, no doubt those published curves are irrelevant. There's probably something wrong with my setup. I'll try and look into it and see I if I can figure something out, and I'll get back to you all if I come up with something.

Regards,

David

Why not put a 2231 in one cab and a 2235 in the other and listen to the mids? If you're set up for bi-amping, shut off the horn to really hear the differance.
I suspect the 2231 might have slightly more upper mids, while the 2235 might have slightly stronger low end. If find that you prefer the 2231s in the 4333s, then stick with the originally speced speakers. There are 2231s out there with the original cones.

Tom

4313B
03-29-2006, 11:49 AM
Well shoot. The 2231H curve no longer exists. Here's the 2235H curve.

I guess you guys will just have to run curves on both drivers and then see where the network needs to be adjusted to your requirements. I always found the 2235H to be an improved bolt-in in the L300/4331/4333.

The 2231 was flat to about 1000 Hz but then had a giant peak at 1500 Hz which doesn't work well with the crossover.

Earl K
03-31-2006, 07:24 PM
Dave,

- This has been said before / but I'll restate it .
- I'd tinker about with your networks Zobel. Heck, it's only a cap and a single resistor. The two woofers needed different Zobels / when crossed at the same frequency ( it's all there in the available schematics ).

- Too bad I'm not local to you. I'd loan you my single 2235/E130 hybrid to see if it's midrange response is more to your liking. Didn't Zilch say he was getting a pair of those made up ( sometime ago ) ?

:)

speakerdave
03-31-2006, 07:27 PM
What would I do, check the inductance of the 2235 voice coil and build a zoebel to make it zero phase? I mean no reactance.

Earl K
03-31-2006, 08:13 PM
What would I do, check the inductance of the 2235 voice coil and build a zoebel to make it zero phase? I mean no reactance.

Yeh, you could do all that & more for the sake of accuracy . The David Weems book can walk you through that process quite well .

Alternately; just find an existing schematic that uses the 2235H (plus has a Zobel along with the same crossover point as the 4333 ) . Then swap in this 2235 specific Zobel for the 2231 specific Zoebel .

- Disconnecting the existing Zobel , is always another option / though the results become a crap shoot .


:)

4313B
03-31-2006, 09:45 PM
The two woofers needed different Zobels:yes: Very likely.
Alternately; just find an existing schematic that uses the 2235H (plus has a Zobel along with the same crossover point as the 4333 ) . Then swap in this 2235 specific Zobel for the 2231 specific Zoebel .:no: JBL uses those conjugates to trim the filters.

Chas
03-31-2006, 10:20 PM
Hold on a second. Maybe I am a relative JBL newbie here BUT, wasn't the Zoebel there to curtail sub 100 Hz impedance issues? Is Zoebal relevant here?

speakerdave
03-31-2006, 10:23 PM
Whatever a Z . . . b . . . l is or does we now have three different ways of spelling it.

Zilch
03-31-2006, 11:13 PM
Didn't Zilch say he was getting a pair of those made up ( sometime ago ) ?What I have learned thus far is that three out of four E140's with "shifted" magnets actually have fractured magnets. The glue holds, and varying amounts of ferrite stays with it.

I've also learned that eBay sellers of E140 baskets that "need reconing" actually mean "virtually worthless - need rebuilding from scratch with new magnets" and get really, really bent when I call it misrepresentation and get my $$$ back from Paypal. :(

Notwithstanding the above, I'll have a pair of good ones back from the reconer tomorrow, looks like, if Dave wants to try them.... :thmbsup:

Earl K
04-01-2006, 06:06 AM
Dave, substitute in some stock Zobel, stolen from a stock 2235H circuit , :blah: :blah: :blah:

:no: JBL uses those conjugates to trim the filters.

Right, thanks for the sobering second thought .

- Dave ( my best guess ), since this is an impedance equalizer / with an emphasis placed on impedance for the moment, retain the present 10 ohm resistor ( in the N333 ) and only replace the stock 20uF cap with a 14 to 16uF capacitor. The smaller capacitor will raise the effective turnover frequency of this equalizer. By keeping the 10 ohm resistor in place , the circuits working impedance in that upper area will be closer to what the network designer wanted / rather than if it was lowered to 7.5 ohms .
- This is still a crap shoot / but at least it's a cheap thrill for those who want to muck about .

:)

Earl K
04-01-2006, 06:11 AM
Whatever a Z . . . b . . . l is or does we now have three different ways of spelling it.

Okay,,, Zoobal ! :p ( happy now ? it's still easier to type than "impedance equalizer" ) :)

Earl K
04-01-2006, 06:29 AM
Hold on a second. Maybe I am a relative JBL newbie here BUT, wasn't the Zoebel there to curtail sub 100 Hz impedance issues? Is Zoebal relevant here?

- Relevance ??, Yes this Zobel is relevant for this application. This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).

- You may be getting this type of conjugate impedance equalizer confused with the conjugate LCR ( though these are typically used only on uppermid & tweeter type transducers .

:)

Earl K
04-01-2006, 06:40 AM
I'm just trying some 2235's in my 4333's. The bass is clearly tighter with lower distortion, but the midrange is just as clearly not as good.

A statement like that leads me to believe that you would really appreciate the extra articulation that the ME150H has in its midrange ( & everywhere else ). I assume the 1500Fe/1500AL also share this trait.

Once again, too bad I'm not local to your area / or else, I'd loan you my extra pair of ME150Hs for a spin in those boxes .


:)

4313B
04-01-2006, 07:25 AM
This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).Here's a picture for those who like a visual. One can see this conjugate has a target of ~ 10 ohms.

Chas
04-08-2006, 09:05 AM
- Relevance ??, Yes this Zobel is relevant for this application. This type of impedance equalizer is used to negate/flatten the typical rising motional (AC) impedance that usually occurs somewhere after 250 to 300 hz ( for JBLs' 15" woofers ).

- You may be getting this type of conjugate impedance equalizer confused with the conjugate LCR ( though these are typically used only on uppermid & tweeter type transducers .

:)

Oh, okay I guess I had it backwards, frequency-wise, I should actually study the schematic before making stupid posts...!:p

Thanks for the graphics, Giskard. The zeebull makes quite a difference.