Sorry, I don't have any pictures. I gave away all the ones I've built years ago.
I've built a few of them in the past, though. I used to have a book (as in paper) called the "Loudspeaker Cookbook
" that I studied before building my first set. Understanding how to match the drivers to the enclosure, what type of enclosure to use, what cross-overs to build, and all that jazz was really useful. I built some pretty fancy (and loud - a high priority for me at that stage of my life) speakers for the "cheap-o" budget I had at the time.
The learning gave me the confidence to believe that I could build a hideously ugly but good-sounding loudspeaker without spending much (I'm not much of a finish carpenter). For in-ceilings, that's not a problem.
The gist of it is simple: ideally, match the enclosure size to the appropriate volume for the driver to perform at the optimal range you're seeking (often indexed by the low-end of the sound and sometimes also by the resonant frequencies). There's many more complicated elements, but that's the simplest. Even below that level of complexity, "a little bigger box is usually better" is a good rule of thumb for low-end (bass) and it can be damped down with various cheap stuffing (damping material) if necessary.
Once size is established (standard non-vented enclosures are simplest and typically lowest volume, thus easier to place out of sight), MDF (medium-density-fiberboard) is essential because it is more solid. A table saw is essential for perfect fits. Pre-drilling for thin screws (#6 or less) keeps the fits perfect. Wood glue is what actually holds the box together; the screws just get it snug while it dries. That's it.
I've done sub-only, bass / mid / high, mid-bass / high, and mid-bass-only enclosures; they all had strengths and weaknesses. I've done closed, ported, and a couple of (not so successful) multi-pass boxes. I've isolated highs or not. I've placed passive cross-overs inside the box or out. I used to have crates of spare parts and would just cobble together whatever I was looking for. The financial factor was amazing - inexpensive drivers can sound pretty good when only asked to produce a limited set of frequencies (cross-over config) and given the exact appropriate environment in which to do it.
Now, I'm spoiled. I have Thiel 3.6s
as mains and use NHT in-ceilings
for surround. I'm running some Axiom M3s
ceiling-hung in my bedroom. They all look MUCH nicer than any box I ever built.