I've been living in rented apartments with small bedrooms for a while and the acoustics of my music spaces has always been terrible, so I finally decided to address it with absorption panels and quadratic residue diffuser (QRD) panels.
I started with the absorption panels in the summer of 2021. Being close to home was helpful because Pops has a (messy) shop full of tools and his years of experience. The design I settled on was fairly simple, but a priority for me was for the absorption panels to not be one-sided so that I could eventually make some stands for them so that they could be freestanding for use as gobos. It would be a butt-joint frame with dowels for added strength, as well as some corner cleats on the inside for rigidity. I have no worries about these panels falling apart.
I went with 5x 2' x 4' panels, 4 of which were 2" deep, the last one 4" deep for use as a bass trap. This isn't really enough for treating a big space, but it's definitely better than nothing, and works fine for a small room or as gobos, as you can see at the end.
So we started cutting out the frame on the table saw, and wound up having to replace the blade for a newer and finer-toothed blade to prevent tearout, because I wanted to the wood to be visible and pretty.
After cutting out the frames, we marked the ends for drilling the dowel holes,
Using the dowel jog to drill the holes is super helpful to keep the drill straight and true, because you obviously can't fit this stock standing up on a drill press.
We did however use the drill press for the opposite joint. We used the painter's tape as a depth marker to make sure we didn't blow out the other side of the wood.
Unfortunately, I didn't get more pictures of the absorption panel process because it was a lot of work and I just wanted to get it done. After assembling the frames with glued dowels and corner cleats, I coated the frame in a clear water-based Polycrylic. I really like the look of it. I then cut rock wool to size and wrapped it in a fine mesh intended for installation in screen doors just to help keep cancer-causing particulate from entering the air, then wrapped that in a black burlap, which is one of the cheapest fabrics you can find, but also looks pretty good for this application.
Description coming soon!