Greetings! I'm certainly no expert, but joined the forum to comment on this thread. It's been a few months, but just wanted to check in with you as someone who has been through much the same ordeal 
http://www.audiokarma.org/forums/in...ankenstein-monster-system-on-a-budget.677257/
From my own experience I can tell you the Altec gear in general is quite valuable, but can be hard to sell. But IMHO the JBL gear you have is even better and more usable, but even harder to sell. In my own more modest haul I ended up selling all the Altec gear, and building a slightly insane home system from the JBL gear. I'm still just getting started, but I can tell you this stuff has amazing potential in a smaller space (relative speaker) running at a fraction of its original rated power. FWIW I believe the 4675x and similar systems were just the name for complete package consisting of a LF box like the 4648A dual 15" and large format horn such as the 2360 series and associated compression driver. I think there were a number of variants on the same theme over the years with different LF and HF sections, from single 15" up to dual 18". The ones you have look to me like the 4648A and 2360 combo, which I believe was incredibly popular during the initial roll out of Cinema THX and digital systems in the 90s, often combined with the big dual 18" sub boxes for the low end in big theaters. EQ'd appropriately in a smaller theater the dual 15s can put out impressive amounts of bass even if they don't look it on paper. There may have been passive crossovers available, but the systems I've seen used something like the 5235 active crossovers which had special cards available to match various horns as part of a bi-amped system.
I applaud you for going as far as you have to try and save these, and would encourage you to do all you can to preserve as much of it as you can and find them homes. I know that's no small task given the size of these things. From what I have seen part of the reason that the old Altec gear has gotten so collectible is that so much of it was destroyed. Those systems were everywhere once too, and when they became outdated for their intended applications a lot of it just ended up in the trash. But this was exceptionally well designed and built equipment from a golden era, and the ones that have survived have gone on to form the basis of really exceptional home systems. In another 10 or 20 years I suspect lots of people will be lamenting all the great vintage JBL cinema gear that ended up in the dump and it will become similarly collectible. I think you are more likely to find demand for these in home hifi circles where they may be seen as a rare chance to own vintage top of the line gear vs. pro cinema / theater audio circles where they are just seen as old. The horns and boxes are hard to deal with due to weight and size, but in those circles they may also be seen to have value as part of the "whole package." But due to size I suppose it will always be a pretty niche market.
If you haven't already I would highly recommend getting on the Lansing Heritage forum: http://www.audioheritage.org, dedicated to preserving and celebrating both Altec and JBL gear. There may be a network of folks on there who can help find homes for it all in the interest of preservation. Other sites where folks might be interested: audiokarma.org, diyaudio.com
Best of luck,
Rob
http://www.audiokarma.org/forums/in...ankenstein-monster-system-on-a-budget.677257/
From my own experience I can tell you the Altec gear in general is quite valuable, but can be hard to sell. But IMHO the JBL gear you have is even better and more usable, but even harder to sell. In my own more modest haul I ended up selling all the Altec gear, and building a slightly insane home system from the JBL gear. I'm still just getting started, but I can tell you this stuff has amazing potential in a smaller space (relative speaker) running at a fraction of its original rated power. FWIW I believe the 4675x and similar systems were just the name for complete package consisting of a LF box like the 4648A dual 15" and large format horn such as the 2360 series and associated compression driver. I think there were a number of variants on the same theme over the years with different LF and HF sections, from single 15" up to dual 18". The ones you have look to me like the 4648A and 2360 combo, which I believe was incredibly popular during the initial roll out of Cinema THX and digital systems in the 90s, often combined with the big dual 18" sub boxes for the low end in big theaters. EQ'd appropriately in a smaller theater the dual 15s can put out impressive amounts of bass even if they don't look it on paper. There may have been passive crossovers available, but the systems I've seen used something like the 5235 active crossovers which had special cards available to match various horns as part of a bi-amped system.
I applaud you for going as far as you have to try and save these, and would encourage you to do all you can to preserve as much of it as you can and find them homes. I know that's no small task given the size of these things. From what I have seen part of the reason that the old Altec gear has gotten so collectible is that so much of it was destroyed. Those systems were everywhere once too, and when they became outdated for their intended applications a lot of it just ended up in the trash. But this was exceptionally well designed and built equipment from a golden era, and the ones that have survived have gone on to form the basis of really exceptional home systems. In another 10 or 20 years I suspect lots of people will be lamenting all the great vintage JBL cinema gear that ended up in the dump and it will become similarly collectible. I think you are more likely to find demand for these in home hifi circles where they may be seen as a rare chance to own vintage top of the line gear vs. pro cinema / theater audio circles where they are just seen as old. The horns and boxes are hard to deal with due to weight and size, but in those circles they may also be seen to have value as part of the "whole package." But due to size I suppose it will always be a pretty niche market.
If you haven't already I would highly recommend getting on the Lansing Heritage forum: http://www.audioheritage.org, dedicated to preserving and celebrating both Altec and JBL gear. There may be a network of folks on there who can help find homes for it all in the interest of preservation. Other sites where folks might be interested: audiokarma.org, diyaudio.com
Best of luck,
Rob
But its been a lot of fun. Yeah, I hear you on the big jbl horns. I still have one more pair I'm trying to sell locally. It's really a shame as I find them much more pleasant to listen to than the newer smaller horns. But I suppose not everyone has room for or wants a pair of 3ft x 3ft horns in their living room. If you were a little closer I'd probably even be dumb enough to try a pair of yours 
