🪵 🔊 Echoes of Tradition: Yaki Sugi Acoustic Diffuser From Repurposed Wood Scraps

In this project, we’ll turn scrap Yaki Sugi wood into a functional acoustic diffuser that improves sound quality and adds a rustic, artistic touch to any room. By repurposing leftover charred wood and using basic tools, we’ll create something both beautiful and effective. Plus, with a French cleat system for easy hanging, you’ll have a sturdy, eye-catching piece that’s easy to mount and remove.

Let’s combine the ancient art of Yaki Sugi with modern acoustic design for a project that looks cool and sounds even cooler!

Materials

1. Oriented Strand Board (OSB): Size: 205 cm x 65 cm (trimmed to 178 cm x 58 cm).
2. Construction Wood: 2 piece of construction wood with size 200 cm x 9.5 cm x 3 cm cut to
3. Two pieces: 60 cm length x 9.5 cm width x 3 cm thickness.
4. Two pieces: 60 cm length x ~4.8 cm width x 3 cm thickness.
5. One piece: 40 cm length x 9.5 cm width x 3 cm thickness.
6. Two pieces: 40 cm length x ~4.8 cm width x 3 cm thickness.
7. Yaki Sugi Wood Scraps (pre-charred from Nakamoto Forestry).
8. Wood glue or other adhesives.
9. Torx screws (3.5 x 35 mm) for securing the construction wood to the OSB.
10. Mounting hardware (hooks, screws, etc.)
11. Protective finish (optional).

Tools

1. Circular saw for cutting the OSB and construction wood to size.
2. Japanese Hand Saws
3. Dozuki 150 mm (link to amazon)
4. Kataba 265 mm (link to amazon)
5. Self made magnetic jig (Thingiverse)
6. Self made jig for cutting the planks (Youtube) with the circular saw
7. Random orbit sander with 80 and 120 grit sandpaper for smoothing the wood surfaces.
8. Electric Drill for driving screws and creating holes as needed.
9. Torx screwdriver bit to match the 3.5 x 35 mm screws.
10. Drill for pre drilling the holes of the supporting frame
11. 6 Wall plugs and 6 screws 4.5 x 75 mm for fixing on the wall
12. Clamps to hold the wood pieces in place while the glue dries.
13. Safety gear (gloves, mask, goggles).

1. Cutting the OSB Base: Using a circular saw, trim the OSB board to 178 cm x 57 cm. This will serve as the foundation for your acoustic diffuser. The size is selected in such way, that when using 3,6,9 or 12 cm pieces, it leaves enough space for the Yaki Sugi pieces to slightly overlap and hide the edges, giving it a clean, polished look.
2. Cutting the Construction Wood: Cut the construction wood to the specified sizes (These will be used to create a supportive frame for the OSB.):
3. two pieces of 60 cm x 9.5 cm,
4. two pieces of 60 cm x ~4.8 cm,
5. one piece of 40 cm x 9.5 cm
6. two pieces of 40 cm x ~4.8 cm.
7. Sanding the Wood Pieces:
8. Use a random orbit sander with 80-grit sandpaper to remove any rough spots or splinters from the construction wood and the OSB base.
9. Follow up with 120-grit sandpaper to smooth the surface and prepare it for assembly.
10. Assembling the Frame:
11. Arrange the construction wood pieces to form a frame on the back of the OSB.
12. The two larger pieces (60 cm x ~4.8 cm) will serve as the bottom supports, while the smaller pieces reinforce the sides and center.
13. Use wood glue to attach the pieces, then secure them with Torx screws (3.5 x 35 mm) using a drill. Make sure everything is aligned and firmly attached to provide a strong base.
14. Do position the support structure some centimetres away from the edge to hide it when mounted later.
15. The screws need to be fixed from the side that later holds the yaki sugi pieces; thus predrilling for positioning is key (see picture with drill)
16. Preparing the french cleat
17. Cut the two pieces remaining pieces with 60 cm x 9.5 cm with an 45° angle into half on the long edge
18. Sand the resulting pieces and attach two pieces to the OSB
19. Keep the two corresponding pieces for later wall mounting

Precut the yaki sugi wood scraps to square pieces with 3, 6, 9 or 12 cm using the circular saw (jig here: Youtube) and japanese saws with magnetic jig (Thingiverse); ensure to have different heights to make the later structure more appealing.

Designing the Diffuser Layout: Arrange the Yaki Sugi wood scraps on the OSB base. Consider both the visual appeal and the acoustic functionality. Aim to create a surface with varying depths to effectively scatter sound waves and reduce echoes. Start with the larger pieces first and allow for some overlap over the support OSB structure.

Attaching the Yaki Sugi Scraps: Secure the Yaki Sugi scraps to the OSB by using wood glue. Apply the glue to the back of each piece and press it firmly onto the OSB. Ensure that the pieces are arranged randomly to enhance the diffusion efficiency. Last attach longer scrap pieces on the left and right to cover up the support structure.

Cleaning and oiling the wood pieces: In order to improve the look and remove left over remains from the wood burning process first clean the pieces with a damp cloth and then oil them with some wood oil at hand.

OPTIONAL: Enhancing Diffusion with Backing Material: To further improve the acoustic performance, you can attach an acoustic backing material, such as foam or fabric, to the rear of the piece. This will absorb some of the sound and reduce echoes. Secure the material to the back of the wood panel before mounting it on the wall.

Mounting to the wall: After the glue has been dried, the french cleat will allow for convenient mounting of the prepared structure. Use a spirit level to ensure that the piece is in line; smaller screws in the part of the cleat that is mounted to the wall taped to the back of the supporting structure give a fast transfer of the correct positions.

Here’s the finished acoustic diffuser and art object! Not only does it add a striking visual element to the room, but it also helps to improve sound quality by reducing echoes. After mounting it, you’ll notice a difference in how sound travels through the space. Obviously it is not optimised for sound diffusion, yet there is a noticeable improvement.

This project was an exciting blend of art and science. The Yaki Sugi wood’s natural beauty and the functional design combine to create a piece that’s both visually captivating and acoustically effective. It’s a perfect example of how art can enhance not just the look, but also the feel of a space.