Bill Epstein Messages: 1088 Registered: May 2009 Location: Smoky Mts. USA
Illuminati (2nd Degree)
The "BatSpeaker" I built 5 or 6 years ago had a Fountek CD-2 ribbon as a supertweeter. The project didn't work because it turned out the 2123s were "blown".
I tried the CD-2s on their own with the 2226 to 1600 and also the Alpha 10 as in the 2Pi. I never was able to coax any of that purported 'high-efficiency' from them and they were ineffectual as tweeters. I don't know if that is a rap on them or ribbons in general but it led me to feel that ribbons work best with other ribbons.
That said, the S-B Acoustics SB-29 tweeter is physically identical to the Vifa and equally sensitive but way out in front sonically. IF you want to build a killer 2Pi, get the $100/pr SB-29s crossed with just a cap.