How to make speakers for your smartphone

Words and photos: Raf Nathan

Smartphone speakers are a great small project for the woodworker. Basically a simple sound box amplifies your phone and becomes a desktop speaker, without batteries or wires. You can expect a surprising boost to volume and sound quality.

1. A drill press fitted with a 40mm diameter carbide toothed forstner style bit was perfect for the job. This gave a smooth and clean hole which required minimal clean-up.

There are a number of designs that pop up on the internet as it is not a new concept. I made four design variations for this project.

The phone needs a relieved section or cradle to drop into which is about 20mm deep. You will have to measure according to the phone model you have. At the bottom of the cradle is a slot to carry the sound into a larger hole which is the ‘speaker’.

2. Three pieces of wood are prepared and ready to glue up.

The first two designs I made were a glued up box that interestingly were not as good at amplifying as the third design which uses a drilled out solid square section of wood. Designs one and two use three pieces of wood: the backing board, a centre board with a cradle to house the phone, and a front soundboard.

3. The three pieces all glued up.

The first design made from oregon worked quite well and then, for the second design made of King Billy pine, I used a thin soundboard, like on a guitar, for the front. In theory this should have given an improved sound quality but actually to my ears it made little difference.

4. Design three has the same 40mm diameter main speaker hole. A 9.5mm (3/8") forstner bit was used for the cradle drilling. Using the same settings on the drill press, a smaller 6mm (1/4") drill bit created the sound slot.

The third design used a solid piece of wood, West Australian sheoak, with a drilled out cradle and a 40mm diameter speaker opening. To improve the design from a lump of square wood I beveled all the outside edges and the front of the speaker opening. This worked well as the hardwood seemed to add more clarity to the emitted sound and the beautiful sheoak grain makes it a desirable object.

5. Design three, almost finished.

For the final design I added in a 5° angle to the front which does no more than make it a more complex looking object. The speaker hole was however drilled at 5° as well, so the hole remained perfectly round. Anyone can cut off a chunk of wood and drill a few holes but if we are fine woodworkers then surely we can add in some details.

6. A bevel was added using a laminate trimmer and a 45° cutter.

7. After finalising the design I made a small batch of speakers from sheoak and leatherwood. For efficiency and safety I left the wood long when machining and cut the individual boxes to final size last. A 5° angle was sawn into the front and the main speaker holes were then drilled, also at 5° to the face. The phone cradle was routed out with a plunge trimmer. With all machining completed, the speakers were then sawn off.

You can have some fun experimenting with shapes and different wood species. These speakers are a great gift item and they do work well.

Raf Nathan is a woodworker and furniture designer/ maker who lives in Brisbane.