4435 diy build

[sheafer]

hi guys
my name is Sheafer from melbourne and i have the jbl bug thanks to you guys and this forum !!

i have always wanted to build a pair of jbl monitors and have decided to have a go at the 4435

here are some pics of the build so far and i have heaps of questions and advice to seek in my next posts

cheers Sheafer

[Lee in Montreal]

Hi Sheafer.

Welcome. It's an intersting project. What woofers are those?

[Champster]

Excellent work! Do you have any pics of the build process & details of the drivers & crossover?

[sheafer]

hi guys
the woofers are re-coned 2225h which will eventually be re-coned into 2234
the horn is the 2425j which i need some advice on to wheather i modify the crossover to suit or change the diaphrams to 2425h and run the otriginal jbl crossover

i have a few more pics of the cabs but not too detailed ,i made them from the dimensions on this site and have still to fit the ports and add the fiberglass
they are made from 18mm marine ply

cheers sheafer

[sheafer]

g,day all
can any one here advise on where i can get the frd/zma files for the 2225h and 2425j drivers ? i need them to import into pcd

cheers Sheafer

[richluvsound]

A pair of 2234's sitting here . Re-coned 3 years ago with genuine JBL CR82235 kits in a K130 Alnico basket . £350 for the pair + shipping

Rich

[sheafer]

hi Rich
thanks for the offer but i need 4 so that means $700 pounds which i think you will find is around $1300 au smackers
i dont think the difference in the low end vrs the 2225h is worth that much especially when they will be used in the home

i can get 2234 recones for $100 each so i will change over later on by reconing what i have for $400 au total



cheers Sheafer

[martin2395]

Wait a second......where are the bassreflex ports? :o

[sheafer]

hi Martin
they were drilled in today
100mm x 18mm deep and tuned to 40hz for the 2225h

can any one advise on if i can fit 8 ohm diaphrams into my 2425j ?

cheers Sheafer

[Robh3606]

Hello

Are you using the stock crossover?? The main difference between the 4430/35 is the power handling down low. Tuning up at 40 hz is going to effect how the woofers sum in the first two octaves. Have you ran any simulations. It's not going to have the reach or the power handling of the stock system.

Rob

[martin2395]

Good job then, they look very good :)

You can use the 8 ohm version (code D8R2425) from the 2425H in the 2425J motor, the only difference between these two is the diaphragm impedance.

[1audiohack]

[QUOTE]
In general you can scale all components by doubling L and halving C but the L pads may present a challenge. Components c9 and l1 are a series resonant that gives CD horn correction. Basically a 6dB per Octave rise to 15 kHz. Yes, bypass caps don't need to be doubled and can be omitted if your cap quality is good.


Getting full level at 15k was a challenge on the 4435 (96 dB sensitivity vs the 93 of the 4430), so having a 16 ohm compressiond driver will fight you on that.


look up the AES paper for some details on the design (Improvements in Studio Monitors, David Smith, Don Keele, John Eargle)


Regards,
David
[QUOTE]



Hi all;

I copied this over from DIY Audio for those here on Lansing folowing along. The David that made this comment is the David Smith in the above referenced AES paper and was employed at JBL and involved in this project. I was going to mention the efficiency issue but Dave's words should be taken as gospel on this subject, in my opinion anyway.

All the best,
Barry.

[sheafer]

Thanks guys
looks like i will be installing the 8 ohm diaphram so i can keep as close as possible to the standard crossover


cheers Sheafer

[Vahe Sahakian]

i have always wanted to build a pair of jbl monitors and have decided to have a go at the 4435



I always wanted to buy a pair of 4430’s for my second system, my main system is a DIY 4 way bi-amplified 4350’s, well I finally located a nice pair of 4430’s, so I took a number of test CD’s to hear how it sounds, this was the first time that I ever heard these two way JBL’s and I must say that it was a huge disappointment, something was definitely missing, the high frequencies just did not have the clarity and the sparkle of older four way JBL monitors that I am used to, and yes I double checked to make sure all the speaker settings were normal and that the higher frequencies were not deliberately turned down.

I must assume that 4430 and 4435 are essentially the same as far as their higher frequencies are concerned, if I wanted to build one of these I would definitely consider implementing a 2405 to help with the upper end, I realize that this is going against the grain and would require crossover modification/complication, but after testing a 4430 I do not see how I can live with the limitations of these two way designs.


Vahe

[1audiohack]

Hi Vahe;

I can agree with your sentiment for the most part. I keep the 4435's in my office and they are dialed flat as my most listened to (time wise) reference if you will. I use them to keep my in head reference honest since they are pretty close to clinically flat. I have been tempted to set a 2404 or 2405 on top but have always just left them be. The 4430's currently live on my tech bench.

My 4350's are much modified and I don't think anyone who has had 4350's wouldn't argue that they are indeed a different animal, quite possibly the most dynamic loudspeaker JBL ever built in one box. How close to flat are your 4350's? Mine are not, on purpose.

Just a suggestion, give your 4430's some time to show you what they are good at before you make them something they're not.

All the best,
Barry.

[Vahe Sahakian]

My 4350's are much modified and I don't think anyone who has had 4350's wouldn't argue that they are indeed a different animal, quite possibly the most dynamic loudspeaker JBL ever built in one box. How close to flat are your 4350's? Mine are not, on purpose.

Just a suggestion, give your 4430's some time to show you what they are good at before you make them something they're not.



I do not know how close to flat my DIY 4350’s are, my guess is that they are not flat.
This is a speaker with many faults as well as strengths, I am of the opinion that the 2” compression driver is responsible for the main fault with this monitor, this driver can easily fill a stadium by itself and at times I feel that it jumps out overpowering all other drivers in 4350, particularly at higher volumes. The stock 3107 crossover does not properly contain and control the compression driver from screaming too loud at times.

Although generally speaking JBL’s are considered better suited for pop/rock as opposed to classical, I am strictly into classical and some acoustic jazz and I prefer JBL sound to other brands for their effortless reproduction of dynamic recordings.

As for 4430, I decided not to buy for reasons cited in my previous post.

Vahe

[1audiohack]

I didn't get that you didn't buy them.

I absolutely love my 4350's. If one could only get a better horn on the 2440/2441 without modifying the baffle I would have done it for sure. I have modeled a rapid flare horn for use with a 1.5" driver that fits the stock cutout for the 2311 but I am not good at getting those type of things finished.

Mine are four way active and I don't think I could ever go back. If I could only keep one pair of speakers, the 4350's would be the ones, warts and all.

Best,
Barry.

[Woofer]

If it's of any help, I can loan you a pair of slots (with a 1uF cap) to try to hear if it's wot ur looking for.
They're not for sale, but I'm always happy to help out.....
(PM) me if you want.)

Woofer (George.)

[high123bid]

Hi,

I have been sitting on a pair of 4435s without cabinets for years and it is time to do something about that. I want to modify the cabinet design to be more like my L150A, so a tower design with JBL blue fronts and Maple veneer.

I understand that each cabinet is 5 cubic feet net. But can anyone help me with the following specs, please?

1. What is the interior volume taking up by each woofer and by the horn?
2. Does the hon sit in a separate internal inclosure? It looks like it does from the cabinet pictures I have seen.
3. If #2 is a yes, does it then reduce the net size of the one woofer cabinet on that size (how big?) or has the been size compensation for the horn enclosure such that net volume is 5 cu ft on both sides?

Best regards, Bo