Hi Troels,
A new member of the Faital-3WC-15 family is born!
I built the pair about 6 months ago. The construction took more than 2 months. Fortunately, Corona offers a lot of time for DIY.
I am already the proud owner of a pair of DTQWT speakers (specifically: http://www.troelsgravesen.dk/DTQWT_Joffrey.htm), and they aren't particularly small either, but my goodness, the members of this family are large! It was a lot of fun building these monsters. And more than that, I learned a lot. A lot about my craftsmanship related to woodworking and a lot about building loudspeakers. Painting is deliberately the way it is. It is a design of my wife and that should be honored!

I made the cabinets, with the reflex ports at the back, braced internally completely asymmetrically, taking into account the correct volume of the cabinets, using fibonacci. The pair is fully mirrored (including the crossovers, although there is no technical necessity there, it is only enforcement of concept). Furthermore, the cabinets consist of an inner cabinet of 18 mm black MDF laminated with 9mm plywood or 6mm plywood. The 6mm parts were later on also laminated with 6mm strips of 22mm plywood. As a result, the cabinets are 6mm less wide at the top than at the bottom. But nobody sees it unless you put the speakers side by side.
When I play loud I hardly notice any vibrations on the front and sides. The rear is a bit more sensitive to that.
However, there is a point to note regarding weight. My speakers weigh almost 55 kilograms each. A few good friends come in handy if you have to move them more often or if the speakers have to be in the attic, for example!

I built and tested the crossovers before so that I could burn-in the drivers while building the cabinets. During the build, the drivers have been able to make themselves heard in a kind of open-baffle construction. That almost led to disappointment after construction. The bass sounded so different from what I heard in the open baffle, that made me also decide to build a real open baffle loudspeaker when budget and time is available again. Well, with the DTQWT at hand, only a pair of 15PR400's will be sufficient, is it....

Anyway, after the build I was not immediately convinced of the quality of the speakers. I actually thought that after the build of the cabinets the drivers would be sufficiently burned in. Nothing could be further from the truth, I only had to find out later.

The mid was clearly yelling at me that it was doing so well and I found the bass very boomy. So I started working on the damping (sometimes more, then less) only to find out after months that I just needed to dampen the mids as described. The bass, on the other hand, needed quite a bit more damping material (I cannot tell why, but maybe the placement of the reflexports has something to do with that).
So, finally, after 4 months, having the current damping level, I ended up only changing the damping of the bass. The mid is still changing very little, but it just gets better and better now (it's still a bit forward but it's getting more refined and transparent).
How do you do that? Deciding what damping is needed while a driver takes that long to settle down.

With the DTQWT I learned for the first time what bass is, but one of the reasons for looking for a replacement for the DTQWTs is that I find them very difficult to place in my listening room. Small changes have a huge impact on the listening image and I thought there could be some more lowerend in the bass. Furthermore, despite or because of my tinnitus, I missed some delicacy in the highs.

Although I will definitely take a closer look at the open baffle, for the first time I do have real bass now: fast, detailed and deep, albeit no subwoofer-quality (but who needs that for music?). So size really matters. And even though I don't have the beryllium version of the tweeter, I'm very pleased with the highs as they are now.

The 3WC-15 is brilliant in placement in depth and in width with a transparency I've never heard before. Together with the fast detailed bass and delicate highs it is, to me, the best loudspeaker I have ever had. By far! But who knows.... after building those open-baffles.....

Troels, thanks for your designs!

Kind regards
Stephan