I'm not one to over think such projects. If it were me I'd jump right in and start by mounting the 12LTA's on a flat baffle to see how they sound. It's not rocket science and MDF is cheap.
The only Lowthers I've heard are my DX3's and I hear no shout. From what I've read the rolled edge whizzer took care of that in the newer models. The DX3's play high enough for my ears so I don't feel a need for tweeters.
Thanks! Definitely will go for the 12LTAs' as they look to be a great match for my sealed Altec 416's.
As for dying to hear Lowthers in OBs at least once, I truly loathe long distance trips, so hikes from Long Island to Lowther America in Chicago are out. But the reason that Lowthers are not seen around metro NY and Long Island must be at least two fold. First, its seems very likely that Lowthers for the most part sound VERY different than most any other kind of speaker, and that as beautiful as it may otherwise be, its tonality is somehow off putting to many ears. Second, is the sad fact that for the most part the DIY audio community had essentially died out here by the late 70s. Even after months of googling I've yet to find anyone in this part of the Northeast who has Lowthers. Jon put me in touch with Dave Slagle
http://www.intactaudio.com/atten.html, but Dave's upstate and only has them in big horns, not in OBs. Housing and property taxes alone in NYC and LI are enormous and time is money, so most people who are serious about high performance audio will go out and audition completed speaker systems and buy them, not build them. And unless I'm wrong, no commercial speaker builders advertising in Stereophile design with Lowther drivers. But I'll keep googling for local Lowther DIYers; maybe I'll get lucky one of these days.
