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.