DIY Corner Bass Trap - Acoustic Dampening

I built this bass trap for the corner of my home recording studio to reduce echoes in the room and get a cleaner sound on my videos and audio recordings. The bass trap is 4 feet tall and is filled with lots of mineral wool (rock wool, Roxul, etc.), which absorbs frequencies. It works very well, and I test it out in the video.

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If you want more specific, fully-illustrated step-by-step plans for making this project, they can be purchased on my website here:
https://www.bobswoodstuff.com/downloads/diy-corner...

Supplies:

• 3/4" plywood
• 1/4" plywood
• one 6-foot 1x6 board
• 3" thick mineral wool insulation (requires four pieces)
• Titebond polyurethane glue

Tools:

• Arrow T50 pneumatic stapler
• 10" combination saw blade
• 8" dado stack
• cordless drill
• impact driver (optional)
• trigger clamps
• extra large trigger clamps

* The Supplies and Tools links are Amazon Affiliate links, and I make a percentage on qualifying sales, at no additional expense to the buyer.

I started with some 3/4" plywood and cut out a quarter circle. Then traced that and cut out another one, and one from some 1/4" plywood.

I used a large protractor to make marks at every 15°, and sandwiched the three pieces together using masking tape and CA glue.

Using a dado stack and a crosscut sled, I cut out notches on my 15° marks.

Then I separated the pieces and spray painted them grey.

I cut 3/4" strips out of a 1x6 (left) to use for the ribs, and I cut a 1-1/4" square from a 2x4 to use as the spine.

I cut a dado into the spine, and cut out a square from the middle piece, to join it to the spine.

I attached the other two pieces to the ends of the spine using 1 screw each.

Then I glued each of the ribs into the notches with polyurethane glue and secured them in place with a pin nailer. The pin nails (or finish nails) secure them in place while the glue dries and also add some strength.

Then I wrapped the round part (the ribs) with some breathable fabric and stapled it in place.

The fabric should porous enough that if you blow air at it, the air will be felt going through to the other side. If the fabric is too thick or non-porous, the bass trap won't absorb properly, and it will be more like a diffuser.

I also stapled the ends. Notice the staples are diagonal. The fabric is 2-dimensional, so placing the staples diagonally secures against force along both axes.

Try to keep the staples in a continuous arc. This will make them easier to cover up later.

Then cut off the excess with a box cutter or razor knife. Make sure to leave some fabric on the outside of the staples; don't cut directly next to them.

I used a ribbon to hide the seam and the staples. First I sprayed adhesive on the back of it, then applied it to the bass trap, making pleats at each rib to achieve the arc shape, and then I used a glue gun to touch up any edges that are not stuck down.

This can take some practice, so do it first on the side of the bass trap that won't be visible when it is hanging, and then when you place the ribbon on the second side it will look better.

I made a template out of cardboard, and traced that with a knife to cut 16 pieces of mineral wool.

Make sure to wear gloves, long sleeves, and breathing and eye protection while cutting these.

Then I put the frame on one end and stacked all 16 of the pieces of insulation into the frame, starting with the bottom section and moving to the top section.

Then I used the remaining fabric to wrap the back of the bass trap, using one piece that wraps around the corner.

Then I cut off the excess.

When you are cutting off the excess on the part that overlaps the other fabric, use scissors instead of a cutter, so as to not cut through the first piece of fabric.

I attached three picture hangers to the top of the bass trap: two on one side and one on the other side.

The whole thing weighs about 14 pounds, so it only requires light duty fasteners.

Notice that the ribbon on this end doesn't look as nice. This is the first end I did and I didn't know to pleat the ribbon. This end goes against the ceiling, so it will not be visible.

Attach three picture hangers to the wall where you want the bass trap to go, making sure to measure the distance from each fastener to the corner of the bass trap and the corner of the wall.

You can experiment with different corners of the room and different heights. It should be covering the height on the wall where most of the sound is coming from, so if you are standing or sitting during your recording, make sure the bass trap is at the same height as your head.

Then hang the bass trap on the fasteners.

It will vastly improve the sound in that corner, but for a whole room it is best paired with other acoustic treatments such as diffusers, acoustic foam, and blankets hanging on the walls.

Thanks for looking!

Make sure to check out my YouTube channel.