Since I have started building new cabs, I thought I could start a new thread as well, since it would describe another building process, and I could share all my mistakes as well (since it's the first time I'm trying this approach).
One thing first, I'm not trying to 'clone' exisiting models or even designs from JBL, so the final product will look a little different to what is most commonly shown here, I hope you won't mind.
Attached pictures are not in the right order, so the second picture below should show my current speakers, product of about 3 yrs of tinckering. They sound good enough (to me) to think that I really want to keep them, but they look shall I say 'industrial'. In the pic below, I'm experimenting with the port tuning, which got me a 'dad, why did you put exhaust pipes on your speakers?...' question.... Time to change this... My target is to have enclosures of the same volume but less visually intrusive, with more fluid forms. I also plan to experiment with building a radial horn, as I believe that those look nicer than the round ones (will have to hear if they sound as good) and might be better adapted to my relatively close listening distance by being less directive.
Since I wanted something more rigid, and with limited parallel faces, I decided for a curved enclosure, like a simplified B&W 800 type. I also selected to build a (simplified again) matrix type framework to limit side walls vibrations. The approach I tried is best described in the first pic below. With this, I will end up with only very small unsupported areas, none of them being of the same size since I purposefully placed the risers in a random manner.
Third and fourth pics are showing the enclosures with the first layer of scarfed MDF cover. This is a feisty material to work with, I did not expect that it would be that difficult to bbend while ensuring good contact point with the framework. In fact, if the first of the two enclosure, I have some areas where contact was not good, and I had to fill some gaps with thickende epoxy - that was mistake Nr1 . Then it's also tricky to cut to exact shape with breaking the individual ribs, which I did when I tried to true the connection with the top panel using a router (mistake nr2). How well, the second cab ended better that the first, as I did not repeated those two minor screw ups.
That's as far as I am today. A second layer of scarfed MDF (both layers are 9 mm thick) will be bound to the first using Sikaflex type floorboard adhesive. I've used it to stick and oak floor over tiles in my living room, it has fantastic adhesive properties, but remain slightly elastic. It's also quite dense, so I think that it will allow the making of a pretty good 'constrained layer'. It's going to be messy though, I'm not looking forward to that... I'll probably make the first of the two cabs later this week. I'll keep posting pictures as I go along, but I'm kinda slow, so it may take a little while.
Cheers from Belgium,