Originally Posted by majestik6
Reminds me of my Gedlee Summas, except with a coaxial compression driver instead of the B&C that's used by Geddes. USSpeaker sells the BMS compression driver, so DIYers might give this a try.
Obviously the coax is a pricey upgrade, and some might argue that the cost is not worth it. But I'd love to hear the difference. I *personally* prefer the upper treble of the small compression drivers to the big ones, and I think diaphragm size plays a big part. (In other words, if you're using a xover point of 2khz or higher, I prefer the sound of a BMS 4540ND or a Celestion CDX1-1425 over anything with a large diaphragm, such as the B&C. BUT if you need a low xover point, like the Summa uses, the small compression drivers won't work; they're too small.)
Sorry majestik6, I previously misunderstood your post. Do you have some measured response graphs? The BMS drivers are quite interesting, but on other forums they complained aboud distortion in the upper end (to be seen in the BMS driver's datasheet too).
So in your summas, you have customized version of the OSWG with a wider 1.4" or 2" throat?