a.k.a., Rob's blanket fort.
CNC files, bill of parts, and design description for a booth, suitable for personal vocals recording, that can be set up or broken down for storage/transport in about ten minutes.
The only exceptional feature of this design is the CNC cut joinery. If you're just here for that, jump to the joinery.
The joinery is also the impetus for me making
it available online. With simple joinery, it is almost
always necessary to put the peices in a jig while glue dries,
or while nails/screws/pegs are inserted. These joints require
a CNC router to cut, but can be carelessly whacked together,
with angular accuracy being determined when you position
the parts on the router table.
With this technique, I was able to achieve stiff squares
that allowed me to stack the top half of the assembly on
the lower half, with the ends of the three foot verticals
varying by less than a half inch.
These are the design artifacts for a small (4' x 4' x 6')
padded space suitable for recording vocals. It can be set
up or broken down in less than ten minutes, and the frame
stores in a space 4' x 15" x 7". It is slightly larger and
many time sturdier than the popular $500 pop-up booths online.
This is not a sound-proof booth. It is designed to absorb the echos of your own voice, not to keep your neighbor's lawnmower from ruining your recordings. It is an alternative to permanently dedicating a space by hanging curtains or acoustic tiles for proper sound deadening. You will still need to find a quiet space, but that space can be your living room, and it'll still be available for watching TV in the evening.
This booth is scaled for me to be able to sit down while
I record. Most people will prefer to stand, but that doesn't
work for me for health reasons.
It's optimized for quick single-person set-up and
tear-down, and for low storage size. It's durable
enough to travel with.
You can do this cheaper with PVC pipe, but there are trade-offs. After you've cut the parts, it takes as much effort to tear down and re-assemble every time you do it. It's never as stable as I would like it to be, and sometimes the joints just don't want to stay joined.
Based on these criteria, this design is best suited for the materials + construction + setup + maintenance. Your mileage may vary.
The design does require cutting the structural members
with a CNC router. Yes, those are 3d printed tabs. You can
do this on a bed 15"x15" if one axis can support
four-foot boards hanging off the edge.
Other things that came in handy were my miter saw, drill press, and hand router, but if you have a CNC router handy, those aren't a great leap.
This presumes a 4'x4'x6' enclosure, but you may want one that's 18"x18"x7', so adjust accordingly. The minimum upper bar length is around 8 inches, but anything less than 22 would require you to adjust the cad drawings. For those who don't hang around lumberyards for fun and profit, a 1x2 is .75" x 1.5".
- 26 feet of hardwood 1x2's
- 70 feet of softwood 1x2's
- 32 1" wood screws
- 32 hidden cabinet hooks with screws (see note below)
- 25 feet of paracord
- Roughly 130 square feet of moving blankets. More if you don't have a carpeted space
- 12 extra large (1-inch) binder clips
I've included links to examples of some of the products, not because I think you should purchase them from anyone in particular, but because I wouldn't know what someone else meant by the words "hidden cabinent hooks with screws."
I built this from 1x2's because they're ubiquitous at Home Depot. My softwood is poplar, and my hardwood is oak. If you go with a softer wood for the vericals, let me know how it turns out. I briefly considered hickory, but I know I can keep oak splinters out of my hand with a 1/4" roundover and a little sandpaper.
This project came into existence because I'm planning to do the audiobook recording for Dystopia: Clempson Goes to Hell. I don't have a space for which I can pad the walls, so I made movable pads. You might notice that the images show the booth set up in various rooms in the house.
The frame involves eight cross-braced structural members
that look like angle brackets [ ] with a diagonal across each
corner. Each face of the frame has a top bracket and a bottom
bracket.
The joins on the angle brackets are cut with a CNC router. I trimmed the part to length on a miter saw. 11" worked out for the diagonals. I also cut the verticals to 11", but if I did this again, I'd cut them at 13.5" because it would make the final product pack better.
There are five attached dfx files that need to be converted into gcode.
I plan to use this for numerous future projects. It is designed to be cut with a 1/4" end mill bit.
Use of this pattern involves:
- creating diagrams of the two parts you want to join
- moving the digrams so that they're overlapped in the manner you want them to be joined in the real world.
- copying the puzzle join pattern onto the two pieces
- moving one of the peices away from the other
- copying the puzzle join, offset by the amount you just moved the one part
- trimming extraneous lines
- Making a closed curve of the cutout parts of the puzzle
Note that the horizontal and vertical parts will also need cutouts for the diagonal part. I found it easist to cut these in a single operation, with jigs to assure perpendicular alignment.
After separating this from the horizontal and vertical parts, I turned it so that the wood could be aligned with the X axis of the router.
The sockets for the hidden cabinet anchor plates
This cut requires a 1/8" end mill bit.
Once you've cut the puzzle join into the verticals, you will
need to flip them on their side and cut these sockets.
You'll want to measure the plates and screws of your
hidden cabinet mounts and cut the slot deep enough for
the screw heads.
When cutting the socket, you want to be sure that you're
offsetting them from the end with the corner puzzle
join.
The screw holes will only need to be cut marginally deeper than the plate, to make it easier to get them properly aligned. DO NOT cut the screw holes as deep as the entire length of the screw unless you're making the brackets out of hardwood. Softwood screws need the extra material to grip properly.
In the original design, I mounted the ancor plates on half of the brackets upside-down so the corner posts bore the entire weight of the brackets. This was more trouble than it was worth. Mount the plates on both sides so that the bracket sits slightly beyond the edge of the supports, then slides towards the middle to lock into place.
I am not happy with the strength of #6 screws for this application. I have not been able to find #8 screws with a head small enough that it doesn't stick up, scraping the vertical support when connected. I'm pretty sure that the right solution would be to use hardwood throughout, but I like the lighter weight brackets.
Six foot long vertical supports seemed like they would be difficult to store, so I split the supports into a 3.5' section and a 2.5' section. this also helped them fit on the router table.
Each of the eight sections will need two pairs of screws. You need to plan the placement of the screws so that the brackets will make a square.
The sockets for the hidden cabinet anchor screws
This also requiresa 1/8" end mill bit.
It sounds like a good idea to just drill the holes with a drill press, but they'll have identical spacing if you bore them with the CNC router. This is helpful for making the brackets level and interchangeable.
Unlike softwood screws, hardwood screw holes need to be cut with just enough clearance that the screw isn't loose in the hole. I had .25" screws, and cut the holes at .23", and would probably go .235" if I did it again.
Having chopped the verticals in half, I was now facing
the issue of making them stay together after assembly.
The solution I came up with was a socket that provided
cleat hitches on all four sides.
There might be an easier way to do this, but I like the
results. It makes it easy to use a single length of paracord
to tie the vertial supports together.
I was thinking that the verticals needed to exist as right-front, left-front, right-rear, left-rear, which doubled the number of CNC patterns required. It also resulted in a final product that was .75" longer in one dimension than the other. Yea, picky, picky.
I could have made all of the screw holes on the verticles interchangeable by giving the corners rotational symmetry instead of bilateral symmetry (image to describe this).
For the actual echo-preventing part, I used nondescript
moving blankets. Two layers of moving blankets is pretty
good at muffling echos. I attaching them to the horizontal
brackets via oversized binder clips.
Getting a 6x7 blanket to stay in place over the 4x4 hole in top, but I clipped the ends to a spare 1x2.