NOT Another Bluetooth Speaker

This is not a speaker made to rock the house. It is more of an experiment -- an idea that I'm throwing out in the wild for the community to examine and comment on.

My goal was to build a speaker that doesn't look like one. Instead, I wanted to make something that was more akin to a piece of art or home decor while doubling as a Bluetooth speaker. This is why I focused mostly on the design and appearance of this speaker, without aiming for high fidelity or anything close to it. Although it did end up sounding okay, actually.

Inspiration for this project I drew from wood veneer art on Pinterest and from Bang & Olufsen's wall-mounted modular speakers. Also, did you know that wall-mounted radios were a thing in the past? Go figure.

In the picture here you can see most of the electronic components used in this project.

Ayima 33mm micro full-range speakers - teeny tiny 3W 4-ohm speakers with okay sound quality. However, I'd recommend something bigger if you want more decent bass. Your box design will have to be different, of course.

Bluetooth receiver module - I only used this module because I had it. There are cheaper modules that also work well, kind of like this one.

PAM8403 stereo amplifier - A simple stereo class D amplifier that can produce about 2-3 watts into 4 ohms from a 5V power supply. Instead of this, you can use a module that has both an amplifier and a Bluetooth receiver on the same board. However, I chose to keep them separate so that I could use the following component:

An isolated 5V DC-DC converter - this little gizmo (not pictured) is used to isolate the power supply of the Bluetooth receiver. This helps to get rid of noise and humming due to a ground loop.

A microUSB breakout board - for providing 5V from a cell phone charger or a power bank

A simple switch - for turning the speaker on or off

*These are affiliate links, meaning that I may get a small commission if you use them. You don't have to, but I'd appreciate the support if you do. The price you pay remains the same in any case.

Additionally, I used fancy woods and veneers purchased on Etsy. The plywood used for the project was bought from a local store.

And here's a list of tools and other items nice having for a project like this:

• Table saw
• Router with flush trim bits
• Sandpaper and a sanding block
• Electric Drill
• Dremel or other rotary tool
• Hole Saw Kit
• Vice
• Clamps
• Flush cutters
• Wire strippers
• Super Glue, Wood Glue, Hot Glue
• Spray lacquer
• Soldering iron

Naturally, this project started on the drawing board. And by "drawing board" I mean my sketchbook. Here's a rough visualization of what I had in my head.

Since my goal was to make a speaker that could double as a home decor piece, I settled on a flower-themed design. I planned on having two flowers on my "canvas", with five petals each made of contrasting wood. The speaker drivers were going to be placed in the middle of each flower. At first, I planned on having extra leaves around the flowers, but I eventually decided to skip those.

I cut the front side of the speaker out of simple 1cm-thick plywood. I wasn't aiming for any dimensions in particular, but I cut the piece slightly smaller than the sheet of veneer I was going to use later. It ended up about 21 by 28cm large.

To make sure that the piece wasn't too big or too small, I made paper cutouts of the flowers from my sketch. The petals were slightly sticking out of the "canvas", but I thought that could be a nice design feature.

For this project, I bought a Bosch holesaw kit (Amazon link). This made cutting the opening for the speakers a piece of cake.

Next, I cut the side pieces of the speaker out of scraps of plywood. These didn't have to look fancy because I was going to cover them with prettier wood later. I ended up with five pieces about 4cm wide. In the third picture, you can see how they're later going to be glued together. While I was at it, I also cut the back piece for the speaker (Picture 4). It's of the exact same size as the front piece.

Using my Dremel tool, I made a small opening in one of the side pieces. This is where a power switch and a USB port are later going to go.

This is a piece of veneer that I got on Etsy. This kind is called bird's eye maple and it looks really pretty in person. I simply glued it to the front piece using regular wood glue. In the second picture, it is clamped between two pieces of MDF so that the pressure gets spread evenly.

On the next day, I glued the top, bottom, left, and right sides of the speaker. My mini clamps came in handy for this step. Note that I placed scrap pieces of wood under the clamp to protect the veneered front side. Sometimes clamps leave a mark if they're squeezing too tightly. Another thing to note is the hole in the middle piece separating the two speaker enclosures. It's where the speaker cable is going to go through later.

Unfortunately, I made the mistake of leaving the veneered side of the speaker out under the hot sun. A couple of minutes later, I heard a couple of cracks forming on the surface. Oops!

But I proceeded anyway. I didn't expect the cracks to be too visible since most of the front area was going to be occupied by flower petals. If you have a guess why the cracks may have formed, please tell me in the comments.

To complete the openings for the speakers, I had to drill through the veneer. I removed most of the veneer with my Dremel tool, then I used my router and a flush trim bit to get a nice, smooth edge.

Next, I cut four small wooden pieces and glued them in the corners of my speaker. This will not only give the whole construction extra strength. It will also provide something for screws to bite into -- the back cover will be held in place with four screws in the corners.

The back cover was cut out of the same 1cm-thick piece of cheap plywood. In this picture here, it already has a layer of walnut veneer glued on top. It is clamped onto the speaker from the back, exactly where it's later going to go. It was important to have it placed in its precise location, flush with the sides, so that it fits later.

In picture #2, you can see me drilling in one of the corners with a countersink bit. This bit not only drills a pilot hole for the screw, but it also creates a nice, angled bed for it to rest flush with the surface, without protruding. You can see a close-up of the screw in place in picture 4.

It was time to hide that not-so-pretty plywood under something fancier. I had some 5mm-thick pieces of walnut that I got from an Etsy store (Link) so I decided to use those. I cut the pieces on my table saw and glued them in place.

Notice that on the back, the walnut pieces protrude enough to wrap the back cover as well.

Why I didn't use cheaper veneer instead? Because the thickness of the walnut created a nice frame effect around the maple front. But yeah, you can probably use veneer if you want to. It's going to be cheaper.

I made the petals out of 3mm-thick mahogany that I got from the same Etsy store. First, I traced the outline of a petal onto the wood. Then I cut the wood with a hand saw and shaped it with my Dremel tool and a sanding attachment.

A few hours later, I had all ten petals ready. Notice that all petals have the same wood grain direction -- from the middle of the flower towards the outer edge.

The last picture here shows the petals in place, but they're not glued yet. I was just making sure they all fit without overlapping.

You can probably glue the Bluetooth receiver to the inside of your speaker, but I decided to be extra fancy and use standoffs instead. These are like little legs that hold the board in place and let you remove it later if you want to.

First, I held the Bluetooth board to the inside of the speaker and marked through the holes with a pencil. Then I drilled four holes for the standoffs. After confirming that the board and standoffs fit, I glued the standoffs in place using 2-component adhesive.

At this point, I was ready to glue the petals to the front. I used wood glue for the job and I put it mostly in the middle of the petal to avoid squeezeout. I used a roll of tape with a heavy briefcase on top instead of clamps. Note that the speakers are there to help me position the petals evenly around the openings.

Next, I covered the speaker with a few coats of simple spray lacquer. I sprayed the front, sides, and the back piece (not visible here).

The USB and the power switch are mounted onto a small board of scrap mahogany. I first gently carved the openings for them with my Dremel tool. Then I trimmed the wooden piece to the size I wanted and sprayed it with lacquer. I glued the USB port and power button after that and soldered wires.

On the next day, after the lacquered speaker was dry, I glued the board with the USB port and the power button in its place -- over the cutout on the side. I simply used super glue for this job.

I glued the speakers using 2-component adhesive. I used a wooden toothpick to gently spread the glue around the rim of the speaker.

I first powered up the speaker without the DC-DC isolating converter to hear how it would sound without it. There was plenty of audible noise on the output, so I isolated the Bluetooth receiver's power supply using a B0505S 5V DC-DC isolating transformer (the tiny gizmo seen on the second picture). This got rid of most noise, except for some slight beeping from the receiver. It wasn't audible while music was playing.

Once all wires were connected, I secured them with hot glue to the walls of the speaker so that they don't dangle around.

After confirming that the speaker works as expected, I closed the back cover.

Picture 3 here should give you a clear idea as to how the electronics are wired together. Power comes in through the micro USB port -- 5 volts from a cell phone charger or a power bank. The 5 volts go through the B0505S isolating DC-DC converter and then to the Bluetooth audio receiver board. The PAM8403 Audio amp is connected to the power source in parallel before the isolator. The audio signal is carried over three wires (left channel, right channel, and ground) from the Bluetooth receiver to the audio amp.