JBL 4350 - Upgrading 3107 to 3155 - Do I need to change to 2441 Diaphragm?

[kelossus]

Currently in the process of building biased 3155 networks based on 4313b's "Final Revision Schematic".

Of note regarding these two networks are the varying crossover frequencies between the woofer to mid-bass (250hz vs 290hz) and the 2405 to the CD (9khz vs 10khz).

Seeing as the HPF/LPF for the woofer is done via a electronic crossover am I able to just leave it at 250hz? I am more concerned with the new crossover point between the CD and 2405 tweeter. Am I going to have to upgrade to 2441 diaphragms or is the 2440 capable of 10khz without any major negative drawbacks.

I have always intended to change the diaphragms to the 2441's so if this is necessary it would be a first priority of mine.

[Mr. Widget]

Yes, the 3155 network is designed for the extended range of the 2441. The 2440 has a very different response curve at the top end.

I wouldn’t worry too much about the crossover between the pair of 15s and the 2202 midbass drivers. Ideally your electronic crossover allows you to massage the crossover point to best fit in your application, but the difference between 250Hz and 290Hz is negligible.



Widget

[kelossus]

Ok looks like I am up for a pair of Diaphragms.

Will leave the Woofer/Mid-Bass filters as they are. I am still utilizing the 2231a/2202a drivers so I see no reason to change it.

[Challenger604]

You would need to change the subs as well to 2235’s

[kelossus]

You would need to change the subs as well to 2235’s

Why would I need to change the subs?

Am I the first person to ever do the 3107 to 3155 upgrade? I can't find any threads where 4313b or someone else experienced states you HAVE to change the diaphragms and the woofer, the diaphragms I can understand though. If it is that important I am extremely surprised it has never been mentioned before or I am looking in the wrong place?

[kelossus]

The 2235h is a recommended upgrade for the L300 which uses the 2231. There is/was no known or spoken about compatibility issues between the 2231 and 2235 in that system so how is the 4350 any different?

Are you implying that there is a technical reason why the 2231A can't be used in the 3155 network? Some sort of impedance difference between the two drivers that would severely compromise the system? Or are you just recommending the 2235H as it is a known improvement over the 2231A.

[Challenger604]

Why would I need to change the subs?

Am I the first person to ever do the 3107 to 3155 upgrade? I can't find any threads where 4313b or someone else experienced states you HAVE to change the diaphragms and the woofer, the diaphragms I can understand though. If it is that important I am extremely surprised it has never been mentioned before or I am looking in the wrong place?

Oh no! You’re not the only one! But are you taking about 4313? The 3155 is for the 4355!
oh whatever. Do what you want...

[kelossus]

Oh no! You’re not the only one! But are you taking about 4313? The 3155 is for the 4355!
oh whatever. Do what you want...

I was referring to forum member 4313b, the crossover I am building is based on his schematic.

As you have offered no reasoning as to why the 2235 must be used I am going to assume you have no idea. You should really not post comments like you did with no reasoninng behind them. If you don't know or unable to explain why then stop. Most DIYer's use this forum as a guide for upgrades and reading a post like yours can throw people off track.

[Challenger604]

I was referring to forum member 4313b, the crossover I am building is based on his schematic.

As you have offered no reasoning as to why the 2235 must be used I am going to assume you have no idea. You should really not post comments like you did with no reasoninng behind them. If you don't know or unable to explain why then stop. Most DIYer's use this forum as a guide for upgrades and reading a post like yours can throw people off track.

Smart ass! The 2235 is the latest of this series. The 2235 has been especially made with the 3155 crossover for the 4345 and 4355! The 2235 has a ring inside to lower the frequency of the driver itself!


I don’t offer anything more because you seem to be very ignorant!

[speakerdave]

Smart ass! The 2235 is the latest of this series. The 2235 has been especially made with the 3155 crossover for the 4345 and 4355! The 2235 has a ring inside to lower the frequency of the driver itself!


I don’t offer anything more because you seem to be very ignorant!

The 2235 has nothing to do with the 4345; that system uses the 2245.

Based on the brochures and every thread about the speakers in these forums the 4350 and the 4355 are both biamp only for the woofer to midbass handoff. The recommendation for a crossover frequency of 290 rather than 250 has not been explained as far as I know (I could be wrong). But since the built in crossover is not in play for that handoff, whatever the reason was, it probably has to do with a difference between the capabilities of the 2231 and the 2235. But it may also simply be JBL designers rehearing the interaction of the 2202 and the woofer. I see no problem with the OP continuing to use the 2231 woofers after his crossover upgrade.

How could the OP's changing the passive crossover for the midbass to treble and treble to tweeter handoff require a change of woofer?

Do you mean to write a sarcastic burlesque of past forum disputes?

[kelossus]

The 2235 has nothing to do with the 4345; that system uses the 2245.

Based on the brochures and every thread about the speakers in these forums the 4350 and the 4355 are both biamp only for the woofer to midbass handoff. The recommendation for a crossover frequency of 290 rather than 250 has not been explained as far as I know (I could be wrong). But since the built in crossover is not in play for that handoff, whatever the reason was, it probably has to do with a difference between the capabilities of the 2231 and the 2235. But it may also simply be JBL designers rehearing the interaction of the 2202 and the woofer. I see no problem with the OP continuing to use the 2231 woofers after his crossover upgrade.

How could the OP's changing the passive crossover for the midbass to treble and treble to tweeter handoff require a change of woofer?

Do you mean to write a sarcastic burlesque of past forum disputes?

Finally an educated response.

[Ian Mackenzie]

All the background on the 2231A-2235H and the 4350 is in Don’s History of JBL article.

None of this information is hard to find. You just have to want to find it.

If you look in the Jbl 5235 active crossover manual the answers on the crossover information for the 4350 and the 4355 is there. http://www.jblproservice.com/pdf/Vin...5%20manual.pdf

The 4350 used the same 5235 crossover card as the 4343. It was a butterworth 12 dB crossover with the frequencies spread so the crossover point is 230 hertz on the Low Pass and and 284 hertz on the high pass.

The 4355 used the same 5235 crossover card as the 4345. It was a butterworth 18 dB card with a crossover point of 290 hertz.