Build your own acoustic treatment

I have finished building my new studio space, and a big part of that was building my own acoustic treatment. I decided to do everything myself due to lower cost, as well as having more control of what I wanted, and also having a lot of fun during the whole process. This article will be split into two sections, first one covering building of the acoustic panels, and the second of the bass traps.
I have done some research prior to purchasing the materials, so I measured my room, found the spots I wanted to treat using pink noise, and then planned what I want to treat them with. The end result was to build and install 8 acoustic absorbers and 4 bass traps. I must thank my friend Max-Antoine and his dad for helping me out during this process, it made for the whole process more fun and a much easier task. For anyone in the US, this video is also fantastic and also gives you the materials that are available for purchase there, check it out: https://www.youtube.com/watch?v=GBHYiWIJhUA

The total cost of the acoustic treatment was just over 300 €, so very cheap for the end result, if you compare it to commercially available solutions.
But let’s start at the beginning.

Part 1 - Acoustic Panels (8 pcs)
After watching a few tutorial videos on building one’s own acoustic panels, I put together a list of items I needed:

• Wooden laths (for panels and bass absorbers) and boards (for bass absorbers)
• Rockwool (fiberglass wool)
• Fabric (black fabric called Deko-Molton in Germany, often used for stage purposes)
  
  

To plan the dimensions, I used Photoshop and took the dimensions of a single Rockwool panel (62,5 cm x 100 cm) as the basis. I wanted to have the panels 62,5 cm x 120 cm, and the bass traps (sofit style) 40 cm x 120 cm, with 40 cm of thickness to absorb low frequencies. I found 40 cm to be enough to cover a lot of lower end in my room, while still not taking too much space in the corners. Due to my room, I could only position the bass traps into the front left and right corners, so I decided to stack them on top of each other, so they go from floor to almost to the ceiling.
First thing I bought was wooden laths for the acoustic panels, as I made the panels first, and the bass traps only later. The local hardware store, OBI, offers free cutting when you purchase wood from them, so I took that advantage and got all the wood precut to spec and ready to go. I ordered enough wood for 8 panels (all 1,8 cm thickness and 7cm depth), which, per panel, came to:

• 2 pcs of 120 cm
• 2 pcs of 65 cm
• 2 pcs of 62 cm (for stronger internal frame support)
  
  

Once I had the wood at home, I screwed it together, predrilling the holes first and then screwing the frames together. Here is the picture of this first step:

It worked really well and the frames ended up being very sturdy.
Then, I ordered the fabric and Rockwool here:

Fabric (Deko-Molton) from the company ge-gra Munster GmbH (highly recommended, super friendly and super fast delivery):
https://shop.textil-muster.de/produkte-naeherei/stoffe/deko-molton-b1-zertifiziert-165gr-lfm-meterware.html
Price: 6,99 € for 1m x 3m, around 65 € in total

Rockwool from OBI:
https://www.obi.de/baustoffhalle/mineralfaser-daemmstoffe/rockwool-sonorock-akustik-trennwandplatte-wlg-040-70-mm/p/8678203
Price: 17,95 € per package, I needed two, so 35,9 €

I also purchased a special knife for cutting fiberglass wool at OBI for 8 €. If you decide to do this, I highly recommend purchasing it, it will make the whole process much easier. Also buy some working gloves and a face mask, as you don’t want to touch (it will itch if you do) or breathe in those fibers when cutting the wool.

Once I had the frames put together and the fabric and Rockwool arrived (it took about a week), I could put it all together. I pre-cut the fabric to the right dimensions, leaving about 10 cm on either side to allow for a bit of wiggle room when tightening the fabric onto the frame. It turned out to be more than enough, although do not forget to calculate the depth of the frame, which also needs to be covered (7 cm in my case, plus 1,8 plus 1,8 cm for the thickness of the wooden laths).

So first, I installed the fabric on the back side of the panel, using an electric stapler to fix it, and making sure it’s stretched tightly.

After that, I cut Rockwool so that one acoustic frame fit 1 whole Rockwool panel and a bit more (20 cm), so I cut apart one Rockwool panel and made 5 times 20 cm pieces out of it.

I then put the wool into the frame:

I made sure it was flat, and since the calculations were correct, it fit perfectly.
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Then it was time for the most crucial part of the process, installing the front side of the fabric. So I put the pre-cut piece for the front on the panel, then turned it around, and started stapling on one side. Then, I tightened up the fabric and stapled the opposite side, and then the other two, but really tightening the last one, to make it really flat.

Here was the result after that:

As the panels would be mounted on the wall on some screws, I wanted to have some distance between the panels and the walls themselves (this also increases sound absorption, as that empty space functions almost as an absorber), I got more wooden pieces, cut them and then screwed onto the back side of the frame, with the longer piece on top (where it would hang onto the screws in the wall), and a short distancing wood piece on the bottom.
Here is the final panel, fully assembled and ready for mounting:

​Two panels were installed right above the mix position, and I used some hooks and small chains to hang them from the ceiling. Here is the photo of the acoustic panels mounted on the walls behind the speakers and left and right (point of first reflection) and on the ceiling:

​Part 2 - Bass Traps (4 pcs)

As at this point I already had experience building the panels, I knew what I had to buy and how to approach the whole process. The main difference between acoustic panels and bass traps would be the amount of Rockwool required, as I planned to build 4 bass traps (2 in each corner, left and right), with dimensions 40 cm x 40 cm x 120 cm. I ended up purchasing:

- 16 pcs of wooden laths from OBI (120 cm, 5 cm depth, 2,5 cm thickness), cutting was free, total price around 40 €
- 8 pcs of 40x40 cm wooden boards from OBI for the top and the bottom (they were cut from 4 pcs of larger boards, cutting was free), total price around 15 €
- 3 packages of Rockwool (10 cm version this time):
https://www.obi.de/baustoffhalle/mineralfaser-daemmstoffe/rockwool-sonorock-trennwandplatte-wlg-040-100-mm/p/5763867, total price 46,05 €
- 4 meters of Deko-Molton from ge-gra Munster GmbH, total price around 35 €

This time, I didn’t pre-build all the frames beforehand, but built them as each bass trap was being built.
Here is how they were put together in a frame:

I also covered the top and bottom boards with the fabric before screwing the frame together, as that made it easier for the installation of Rockwool.
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Then, I had to cut all the Rockwool, cutting out some wool for the wooden laths to have space (2,5 cm thickness), and then placed it inside the frame, and it fit perfectly. I used 8 panels of 10 cm Rockwool for each bass trap, 4 stacked on top of another, totalling to 40 cm of thickness.

Once I had the frame and the Rockwool inside it, I only had to take the fabric (which I have pre-cut to 180 cm x 150 cm), and wrap it around the bass trap, stapling it to one side first, then slowly rotating the bass trap, tightening the fabric all the time, and then stapling it at the end.

In the end, I cut off the excess fabric and staple anything else that needed stapling.

The final step to complete the acoustic treatment was to take a simple sponge, and clean the panels, as well as the bass traps before mounting them. The fabric now has a nice soft touch to it, and it looks amazing, so once we positioned them, the whole room became much more acoustically balanced. And it turned out to look pretty cool, too!