I've had a pair of Karlsons sitting around empty for a couple of years now. They originally housed Altec 604E; my plan was to put a pair of Tannoy 3836 15"
coaxials in them, but the Tannoys were front-mount and just wouldn't fit past the
"wings".
Doubtless a slight knowledge of carpentry would have helped.
But I still have a pair of "full range" Electro-Voice SP-12B, a recommended design for
the K15; just need to make a baffle for them.
And in case anyone's curious and doesn't already know about it, there's Job Ulfman's
"Karlson Speaker Home Page", a web site dedicated to the Karlson design, with quite a
bit of DIY discussion: http://home.planet.nl/~ulfman/
Cheers,
Joel