dubkarma
10-27-2018, 11:59 AM
Early days yet, with much crossover/EQ work to be done once I start up the REW and begin measuring, but using the old JBL M553 active analogue crossover, they're already quite listenable.
. . .So for a few years ago I have had lying around from eBay purchases a pair of JBL 2450SL compression drivers and 2332 horns as well as a pair of D2430K for which I later purchased a pair of those plastic "STX825" horns. Question was what to do with them.
Long story short, acquired a new pair of 2216Nd-1 drive units and got a local cabinetmaker/speaker designer to copy the volume and tuning of the 4367 cabinet (180 litres, 30 Hz tuning—hope that's right!). Because I wanted to keep HF section in a separate module to facilitate trying different horns and drivers, I had the LF cabinet made slightly wider and deeper, but not as tall as, the 4367 cabinet. Plus, good idea or not, I used birch plywood, with double thickness front and rear baffles, rather than the MDF used in the factory cabinet. Internal bracing was copied from the 4367 cabinet, but I added some vertical bracing as well.
The HF driver and horn were placed in a simple plywood "sleeve" with room enough in the back should I eventually opt for a passive crossover. Will later try the D2430K/STX825 horn in the same way. And possibly, eventually, one or both drivers with the M2 horns.
I doubt whether the simple 24 dB L-R slopes and CD horn EQ offered by the M553 crossover will prove to be optimal, but it's a place to start. So far, the major problem is that the result is enjoyable enough for listening that it's leached away some of my motivation to "get measuring!"
The photos may suggest that I do my listening while attached to the ceiling. In fact, the uploaded photos appeared upside down, and I haven't figured out how to rotate them. . .
8262782628
. . .So for a few years ago I have had lying around from eBay purchases a pair of JBL 2450SL compression drivers and 2332 horns as well as a pair of D2430K for which I later purchased a pair of those plastic "STX825" horns. Question was what to do with them.
Long story short, acquired a new pair of 2216Nd-1 drive units and got a local cabinetmaker/speaker designer to copy the volume and tuning of the 4367 cabinet (180 litres, 30 Hz tuning—hope that's right!). Because I wanted to keep HF section in a separate module to facilitate trying different horns and drivers, I had the LF cabinet made slightly wider and deeper, but not as tall as, the 4367 cabinet. Plus, good idea or not, I used birch plywood, with double thickness front and rear baffles, rather than the MDF used in the factory cabinet. Internal bracing was copied from the 4367 cabinet, but I added some vertical bracing as well.
The HF driver and horn were placed in a simple plywood "sleeve" with room enough in the back should I eventually opt for a passive crossover. Will later try the D2430K/STX825 horn in the same way. And possibly, eventually, one or both drivers with the M2 horns.
I doubt whether the simple 24 dB L-R slopes and CD horn EQ offered by the M553 crossover will prove to be optimal, but it's a place to start. So far, the major problem is that the result is enjoyable enough for listening that it's leached away some of my motivation to "get measuring!"
The photos may suggest that I do my listening while attached to the ceiling. In fact, the uploaded photos appeared upside down, and I haven't figured out how to rotate them. . .
8262782628