JBL 4331 rebuild using 2445J and JBL woofer - would this be a good idea? Help pls!

[Mazza]

Wow Ian - DD67000 that's quite some exhalted company the the 4331 can keep up with!

The DD66000 inspired me to convert my beloved Klipsch KG 5.5's to a 2.5way after I inspected the crossover schematic.

I would ideally completely restore the old ladies. Especially seeing as they are that good comparatively.

And no I've not ever heard not seen an all original 4331 or 4333.

I'm in two minds about my way forward with the cabinets. Finding the original mid horns and CD's seems like a long shot in Australia or for a reasonable price anywhere these days. The crossovers even more unlikely.

I can mostly recreate and redesign the crossovers from original schematics and my own measurement rig.

I've toyed with using the modern JBL HL1425 with the D220ti as a near alternative tho not exact replacement to stay close to the original design and use the 2502's to again get close if not completely original.

I'd then use the 2445's with the 2226's to create a copy cinema series 4507 clone in a new enclosure.

[Ian Mackenzie]

The 4331 isn't a DD67000. It just much sounded better than we expected in comparison.

This is the thing.

A very good loudspeaker can sound so so if not set up so it has a fighting change.
Even some dated legacy systems still shine when set up in the hands of an expert.

The 4331 has stock original components.

The system was placed in two milk crates central in the room well away from room boundaries. Something to bare in mind is these low boy systems have the woofer and horn relatively close to the floor. Raising them well off the floor does reduce the influence of the floor particularly the bass and midrange. These monitors in use were used above ear height in control rooms and were the industry standard for quite a while.

We tried a number of active crossover settings and measurements taken with REW at 5 different positions. Unfortunately I don't recall what Greg settled on but they were closer to 4th order acoustic slopes. Some room correction was applied with DEQX. What you end up with is hearing what some good classic driver designs can really do. The basic 2 way JBL system is the cornerstone of JBL systems. Some are enhanced with LF and Uhf drivers but they are basically two way systems. The drivers have improved over time and so has how they are used.

The JBL networks back in the day were about low losses and power ratings according to Greg Timbers. They focussed on the drivers. At the time (60's to70's) network design was in its infancy. What Greg did was improve a number of these legacy systems when he arrived at JBL with revised networks and drivers. Greg went on to develop some new systems that started out at home. Greg become a master at blending multi way loudspeaker systems and designed numerous transducers. You can read about this in the library and who were the founding fathers that shaped the evolution of JBL studio monitors. The Array series and the Everest DD65000-DD67000 were some of the most innovative systems that Greg was involved in developing.

Unfortunately Greg was unceremoniously separated from employment on 30 September 2015 ending a 43 year career.

They may as well have thrown the baby out with the bath water. Greg is still evolving his system at home which is now very sophisticated and has recently designed and fabricated a new horn using 3D printing for his home theatre system. There are many things to like about Greg. Its the way Greg applies his mind to solving practical problems that jumps out at you taking an idea and making it real. Greg walks the walk and his designs do the talking.

https://en.wikipedia.org/wiki/Don%27..._the_bathwater

[Mr. Widget]

This is the thing.

A very good loudspeaker can sound so so if not set up so it has a fighting change.
Even some dated legacy systems still shine when set up in the hands of an expert.

+1

The 4331 and the rest of the 43XX series are far from perfect, but they can be made to sound surprisingly good. The 4331 has the advantage of having less going on than the others so there is less to “correct”.

FWIW: If I ever find the time and space to put them, a pair of DIY 4331 or 4333s is on my short list.


Widget

[Ian Mackenzie]

Ditto.

I have a pair of mint LE 85, 2312/2307 and reconed 2235 waiting for that project.