I've been thinking about a nice project to spend a couple of months with.
I own a pair of Danish made JBL LX-66 speakers. I like their sound, and would like to make them even better.
On further examination, I found the cabinet to be one of the weakest I've ever seen. It's not even made out of MDF - it's just particleboard. There's no bracing inside.
The speakers have 2 8" woofers and have quite a lot of bass. I'd assume such a weak cabinet, combined with so much bass power, is not exactly a recipe for uncoloured sound.
My plans are to build a new, heavily braced 1" MDF cabinet in the shape of the L-250 JBL speaker, and use the original crossover and drivers for the LX-66, while mantaining internal volume constant.
I calculated the internal volume of the LX-66 as being 107L. Then, after measuring the 4" port on the back, I arrived at a 40 Hz tuning point.
I'd also like to drop said tuning point at least 5 Hz. My goal would be having a 30 Hz tuning point, at the expense of efficiency. I always thought the speakers were a bit underdamped, anyway.
Do you think this would be a worthy project? I don't know - the 26Ti tweeter is not recognized as one of the best, and the original speaker is in good shape. I'd like to build it because I got a new low power tube amp, and think the JBL's would be ideal (with their high efficiency rating - around 94 dBs!).
Also, I've been looking for the T/S parameters for the 408G woofer driver, but haven't been able to find it, so I can't determine the speakers' response after re-tuning the cabinet, so I'll have to test them by ear.
Any opinions will be very welcome!