Great build. Thanks for the pics, they really help.
I thought I'll chip in with a few points about the physical design and construction.
- For your next design, I suggest moving the tweeter much closer to the midbass. We strive to get to ideal point sources, and tweeter-midbass distances do make a difference to the coherence of the sound, specially for critical nearfield listening. In fact, the midbass units you used have straight-cut flanges to allow close placement of the adjacent driver.
- Don't put the tweeter on the vertical centre-line of your front baffle -- offset it to one side by at least an inch or so. The theory says that the distances from the two edges should be 1.6:1 or some such ratio. Offsetting it helps even out the SPL by distributing out edge reflections across a wider range of frequencies.
- The largest panels in this enclosure are the side panels. In other words, spurious vibrations are most likely to emanate from them. I would suggest horizontal braces, not vertical, for such enclosures, so that the side walls are properly locked down and stiffened. (If I understood your design right, you have only one brace, which is vertical.)
- Just my preference, but I go with 25mm MDF. I don't see what is to be gained by using thinner, considering how much of a struggle it is to build inert enclosures.
- I suggest not using MDF for braces. Use 20mm (or 18mm, depending on the brand) ordinary commercial ply. And make sure you put a 2" wood screw through the outer wall into the brace plywood edgewise every 4-6 inches, in addition to Araldite. This forces the brace to lock down on the outer wall tightly. My carpenter missed the screws for my Darbari lower enclosure, and I immediately heard the effect and had to force him to put them in.
- Make the grill frame from thinner material if possible. I tried making a grill frame once, using stainless steel rods maybe 3-4mm diameter. It worked out really well, because it's strong and very thin. Any metalwork shop which makes stainless steel drawers and cages for kitchens will be able to make them for you.
- I use double-thickness for the front baffle, since that's the most important to get inert, by far. In other words, I use 2 sheets of 25mm MDF stuck together to give me a 50mm front baffle.
- For your next build, don't bother with rounding out the edges of the cutouts in your braces. Sharp edges there shouldn't impact the sound audibly. You have taken enormous pains to do a finely crafted job -- maybe this will save you a bit of labour. Sharp edges versus rounded edges make an impact on the sound only for directly radiating sound which is in front of you and radiating towards you, and this too impacts only high frequencies. If these edges are inside an enclosure, their impact won't be audible outside the box. (Bevelling the rear opening of the midbass cutout is a different matter -- that bevelling (not rounding-out) is needed to avoid standing waves which otherwise may form in the short cylindrical tunnel behind the speaker cone.)
- You've done lovely rounding of the baffle edges, which is the textbook prescription to do. But I am now beginning to feel that just bevelling them 45-degrees will probably give almost identical results acoustically, and are sometimes easier to build -- you don't even need to run a router along the edges. May save you a bit of labour.
These are just my thoughts. There are a thousand different ways to do the same thing in DIY.
It's always great to see how much effort you put in for your builds and how well you finish your enclosures. :clapping: I really love well-finished DIY, and I love your dedication to good finishing. Commercial speaker manufacturers apparently spend upto 60% of their costs on finishing of enclosures, I'd read somewhere.
