Altec Biflex / RCA LC-1A listening impressions?

Dear Forum Members! This is my first post.

Lately I have been searching information about the 15" Altec Biflex driver, and found it here. Fancy the idea of a 15" cone widerange alnico driver. Does anyone have listening impressions about this driver to share?
Qts should be .49, so could it eventually be suitable for a (large) open baffle setup?

The RCA LC-1A, the speaker of my dreams though I haven´t heard it yet, seems to be so difficult to ever get hands on a pair of these days... Comments on the sound characteristics of this driver are also much welcome!

At the moment I use a vintage Philips 12" driver made in 1953 for pro use in cinema. This "Klangfilm style" driver has a light conical papercone, large alnico motor and phenolic spider. Remarkable good resolution up to around 5Khz, but it lacks some level from 40-200Hz. I consider to have JBL LE5-10 aludomes mounted on them to increase the HF output.

I only play vinyl on an EMT 930 tt + 2A3 SET amp.

Thanks a lot in advance for any reply!

Best regards,
Thomas.

Altec drivers that used coaxially mounted tweeters were called Duplex speakers. Altec's Biflex speakers were made by cutting the cone in a circle at near mid way and gluing it back together with an elastic cement. This allowed the inner cone to respond a little more quickly and produces slightly more high frequency, while the outer portion seemed to follow mostly the lower frequencies.
I've never heard these, but suspect that the Biflex design did add a little more top end over the standard one piece cone. I also suspect that the Biflex design couldn't hold up to as much SPL as the one piece designs.
...just my guess on all this.

Tom