4350 project

[rakoni]

Hello all
First sorry for my English but I will try.
I found empty boxes 4350 and now I am baying components but instead of original I decided to make some changes.
4 x LE 15a (I try them in 4343 before and they sounded very nice)
2 x K 120
2 x 2445J
2 x 2402

up to now I have all of this except network (3107) not easy to find
here in Europe.I would like to hear any comment from you ,I think that I am improveing system but maybe I am doing just stupid changes.

For amps I have
Phase Linear D500
Phase Linear 400
Pre amp HK citation 25

Regards to everybody
Rakoni

[Triumph Don]

Well I think you have a good pre amp, just make sure you have some low amp in line fuses [from personal history] with those Phase Linear [once again, IMO] grenades. As for the rest, as luck would have it, the expert [ah..world wide?] on 4350's is a member here. He will be posting soon!

[speakerdave]

To me it is interesting that your choice of components moves away from the stock 4350 and toward the original prototype of the speaker which became known as the "Texas bookshelf" speaker. that speaker used the LE15A, the D131, the 375 on the 2311 horn and the 077.

The 3107 shows up on ebay with fair regularity. I have a pair myself but you don't need them, because at this level of speaker engineering crossovers are made for certain combinations of drivers, so the 3107 does not apply to what you are doing.

David

[rakoni]

Thanks Don and David for your opinion so I will order
networks for my drivers and then I am missing active
filter 5235 or m552 ?? I never use them before so which one is better
in my case?

[speakerdave]

I think your idea is interesting, as I said before, but I wonder if you really know what you are getting into by diverging from an existing JBL design in your choice of components. Your question about the 5235 and 522 would indicate that you do not. Those crossovers are both designed to provide just one crossover point. Also, I'm not sure what you mean when you say you are ordering crossovers.

The prototype for the 4350 was made by the engineers at JBL who are geniuses at designing crossovers to blend the sound characteristics of different drivers. Can you do that? That speaker was designed to show what JBL speakers could do for the reproduction of rock and roll recordings. Is that what you want?

If you like a very forward sounding speaker, you could hardly do better than to use the original components for the 4350 (as I understand; I haven't heard it). Using the components you list there's a very good chance your experimental speakers will really not sound very good at all.

How much reading have you done on this forum? I would suggest you spend about a week searching the old threads for information about the 4350, about all of the drivers you are not planning on using that were in that original speaker, all the drivers you are talking about using, the crossovers you have mentioned, and the many threads dealing with past efforts to build good speakers while striking out in strange new directions with the choice of components. Read the threads dealing with designing crossovers to blend different drivers together so the combination is capable of reproducing music. None of this is easy. Also explore the library here and the various resources at the JBL PRO website regarding the drivers in question.

Why not get copies of the original 4350 components and rebuild the speakers as stock?

David

[rakoni]

Hi David
About crossovers I don't know nothing,just I heard that for 4350 I must use 3107 plus one active like 5235 ,why both of them I really don't know.
Like you said I must do a lot of reading.
Rakoni

[speakerdave]

The original woofers for the 4350, the 2230 and the 2231, and their recones, are no longer available unless they appear on the used market; that happens occasionally. The 2235H is the replacement for those drivers. That is the woofer that would be recommended. If you want to use the LE15A instead, it will not sound exactly the same. Speculatively (I have not done this) I would expect that two LE15a's would sound a bit bass-heavy.

I would suggest you forget the K120. That driver has a sound tailored for playing guitar, and its rising response in the midrange combined with the two LE15A's would give your speaker a sway-back response curve that would sound fat on the bottom and shrill at the same time. I don't think you could listen to a speaker like that for very long. I would suggest you go with the 2202H. It is not a rare driver and usually not very expensive when it shows up on ebay. By reputation it has plenty of pop. If you want the Alnico magnet, then find some Alnico frames (2202A, D131, K120) needing rebuilding and have them reconed as 2202's.

The 2445J motor would be OK. The 2440 in the original used an aluminum diaphragm with a half-roll surround, though, and that has a different response from the stock titanium diaphragm of the 2445J or the later aluminum of the 2441. This is not a big issue unless you happen to end up using the original 3107 crossover. If you use the 3107 you must use a 2440-type diaphragm or modify the crossover.

Substituting the 075/2402 for the 077/2405 makes no sense to me. The HF to UHF crossover in the 4350 is around 9-10k, and the 075 only goes out to about 15k. But, I think you could do it if you like the sound of that driver over that frequency range.

The configuration for making a 4350 would be: 2235 (x2), 2202H, 2440/375 with original diaphragm type on the 2311/H93 with 2308 lenses, and 2405/077. Crossovers would be the 5235 with the special cards for the 4350 and the 3107. The 5235 is an active line-level crossover that biamps the speakers at the crossover between the woofer and the midbass cone. It uses plug-in circuit cards to achieve the frequency division, and JBL tailor-made cards for certain speakers, including the 4350 and 4355. The 3107 is a passive high level crossover that provides filtering and frequency division for the upper three elements.

What would actually be recommended would be to upgrade to a 4355. You would use the 2235 (x2), the 2202H, the 2441/376 with correct diaphragm on the 2311/H93 with 2308 lenses, the 2405/077. Crossovers would be the 5235 with the cards for the 4355 and a handmade copy of the updated, charge-coupled crossover for the three upper elements of the 4355.

A final note: I have not built or even listened to a pair of 4350's or 4355's. However, I have followed all of the discussion about them in the forum because I had planned to build some, and I have assembled all of the necessary components for a pair of 4350's (except the 2440 dias). So nothing I have said comes from the standpoint of expertise; rather, I am sharing my accumulated opinions about a work in progress.

David

[Mr. Widget]

I have messed around in these waters a bit myself and would agree with every recommendation that Speakerdave has made. As for the LE15A vs. 2235H comparison, you may find the LE15As to have a warmer sound, but they lack the deeper bass extension of the 2235H. I have used both drivers in the same cabinets and found the 2235Hs to have deeper bass and are a step up if accuracy is your goal. If you are after a vintage sound, the LE15A certainly fills the bill and is a nice woofer too.


Widget

[yvonf]

The 2445J motor would be OK. The 2440 in the original used an aluminum diaphragm with a half-roll surround, though, and that has a different response from the stock titanium diaphragm of the 2445J or the later aluminum of the 2441. This is not a big issue unless you happen to end up using the original 3107 crossover. If you use the 3107 you must use a 2440-type diaphragm or modify the crossover.

I also plan to rebuilt a pair of 4530 and i baught a pair of empty grey enclosure :p
I planned too to buy 2445 but forget it :eek: : the ferrite doesn't have enought place in the 4350 ! (2202 enclosure is to close !)

Today i have 2441.

BTW can you help me :

I only have 2 x 2231 (alnico) and cant find two more ... :(
I have 2441 and i can easily (a bit more !) buy 4 x 2235 : SpeakerDave your idea to build 4355 is a good idea but what about events :confused: . On 4350 you have six (!) events and on 4355 only two (bigger) :confused: :confused: :confused:

Thanks for any comment !

Yvon

[speakerdave]

. . . . your idea to build 4355 is a good idea but what about events :confused: . On 4350 you have six (!) events and on 4355 only two (bigger) :confused: :confused: :confused:

Thanks for any comment !

Yvon

Ok. I gather you are talking about vents or ports. The larger sizes were probably chosen to reduce noise in the openings. Don't worry about it; they will work as is.

David

[yvonf]

Ok thanks a lot for this information.:)

yvon

[speakerdave]

You're doing just fine.