I built JBL 4343 clones in 1978 with the help of my stepfather. All I had was the sales literature. I wrote to JBL, but they wouldn't provide more information. I used 1" and 2" oak glue blocks inside. Parts of the back are 2" MDF. I banged on the outside with my fist and added material to get rid of resonances. The baffle panels are two layers of (void-free) ½" marine plywood. I seal them with cork. I was going to use veneer on the outside, but opted for Wilsonart teak plastic laminate. It has better sound characteristics, has held up extremely well, and fools woodworkers. Applied polyurethane to all internal surfaces to prevent moisture intrusion. I replaced the 2231As with 2215As. I replaced the 2307 horns and 2308 diffraction lenses with Transylvania Power Company "The Tube" (Karlson couplers) on the 2420 compression drivers. That got rid of the nasal tone and allowed them to go above 20 kHz. I couldn't afford the 2405s, but decided I didn't need them. I borrowed an HP Wave Analyzer to tune the 4" ports, which are much longer (with elbow), and tuned for smooth lower response. I used polyester rather than fiberglass batting. It took a lot of experimentation to get the amounts and locations right. I bought active crossovers and tri-amped, mainly because I didn't feel skilled to design good crossovers. Had the surrounds replaced about 25 years ago. I've never wanted different speakers. www.diyaudio.com/community/threads/fs-pair-of-transylvania-power-company-the-tube.316728/
Nice job on the conversion. On DIY projects with well known entities like jbl or Altec, they have an insane amount of resource materials that can help guide you and others on the the best way to get the most out of their products, such as vent size, cabinet dampening, crossovers, etc. Altecs usually require minimal dampening like only 3 sides vs all 6, please take this in the way it’s given as a tip not a criticism because your implementation is pretty damn awesome
The inductors should be placed right angles from one other. Because it stops magnetic interference from each other. Look it up in crossover building on RU-vid. It actually shows the noise created.
Hi Robert That is correct. and it would be relevant if I where designing and building my own crossover. This is the Great Plains Uadio crossover sold for the unit
Well, true - I swapped them out for a pair of Werner Jargusch phase corrected crossovers instead of changing the original part. I don't really like modifying, especially when it's so easy to just build another :) @@robertthurston6858
Hey pal! How are you liking these? I am planning on doing something very similar with the same drives as a first DIY proyect and I am curious if you are happy with it.
Great job. A m a fan also of JBL retro speakers , building myself now a L100 clone . Nice record at the end there . Could you tell me the artist ? And have you som recomandation jazzy music for good 12 inch woofers ? Hilsen Tore from Norway
They sound as big transparent studio monitors. I like them, but they are also very revealing and every listening session becomes a critical listening session with all details and errors highlighted. I do love them, but the Altec (which reminds me of Tannoy Ardens) have a lot of the same clarity while being a little bit more relaxed. So I find myself enjoying more records that sound awful on the JBLs
Building your speakers in an apartment is … messy. Using a bit router without a vacuum cleaner connected is….. dusty. Serious projects you are committed to.. Keep up the spirit :-)
