Unique 3D-printed Bluetooth Speakers

Traditionally speakers are cube shaped. This is most likely due to the limitations of the manufacturing process, as most speakers are made of MDF-sheets. With the advent of of 3D-printers this limitation is no longer an issue. This realisation was the inspiration for the project. The speaker dogma speaks only about squares and cubes, the round speakers are nowhere to be found. There is only one way to go and it is to the unknown. 

The initial design was done in Adobe Illustrator. Working with the shapes given by the speakers, the design was born. There was no need for anything else. Two circles merging to infinity.

A 2-dimensional speaker design doesn’t show the whole picture, so a simple extrusion of the flat surface made the design complete. Using this sketch as a basis the 3D-model was a breeze to shape up. This guide will go over the design process of a similar speaker and what to consider.

Parts list:

1x ZK-1002 Bluetooth Amplifier Board (TPA3116)

1x Speaker wire

2x Acoustic wool panels

4x Speaker elements

4x Female banana plugs

4x Male banana plugs

16x M4 bolts

16x M4 heat set insert

Tools needed:

3D-printer

Soldering iron

Hot glue gun

The speaker looks like a “∞” so it has a symmetry from the middle. As it uses two of the same element, so we only have to draw the speaker once and copy it.

1. First draw the contour of the speaker element. Pick up the callipers and stay accurate; measure twice, draw once. It is never a good idea to build something on shaky pillars. 
2. Copy the speakers silhouette and offset it by a reasonable amount. This distance will set the scene for the speaker. Too close and they look cramped, too far and they look distant from each other. 
3. Draw a circles from the midpoint of both the speaker elements. This will be the foundation of the design, so choose the size wisely. The only limit is the print bed, so max it out. With a larger area the speaker doesn’t have to be as tall to reach the same volume, so there is a bit of a design trade off to do there. Some like them long, some like them thick. 
4. Trim off the intersecting parts and complete the junction of the two circles. This gives you a great shape like an eight.
5. Do a fillet of where the circles crossed each other. You don’t want the design to strain the eyes or the ears, make it smooth like jazz.  
6. Offset the great shape by half thickness off the wall you plan to erect. Mexico won’t pay for this wall, you will. The problem is that you want a solid wall that doesn’t resonate too much, but also a thin wall to save in on plastic. However, it is always better to go too thick instead of too thin. But don’t worry too much, you will double the size anyway. 
7. Copy the two outer lines, now it is time for the backside of the speakers. Using a carbon copy guarantees that the next part will fit like a glove. 
8. Offset the inner of the two contours by the width of the wall you want to have. This is where your wall reach it’s final form.
9. Add two holes in the middle for the banana plugs. Measure the ones you have and make a hole accordingly.
10. Extrude the middle of the plate by the thickness of your walls. This gives you a solid and uniform base.
11. Extrude the inner shape by a bit less than the length you want on the speakers. Remember that this gives you the volume of your speaker.
12. Extrude the outer contour by the length that you actually want. This part will stick up a bit from the plate which the speakers are connected to.
13. Now start with the front plate. Extrude the middle of the speaker plate and the screw holes the wall thickness. Now all the outer parts are the same thickness. Hopefully you chose a thickness that will be rigid enough. 
14. Extrude the outer contour half of the wall thickness. This part will fall in to place on the back plate later on.
15. Extrude the rings by slightly more than the wall thickness so it gives a bit of pressure on the rubber seals. This is important, as seals are meant to seal.
16. Extrude the stand-offs by as much as your speakers desire you to do. Every speaker has their own perfect height. 
17. Chamfer the stands-offs, both for a nice look and so it fits your speaker.
18. Fillet the rings a bit, you want that smooth edge pressing up on the seal. 

1. Print both parts of the speaker enclosure with solid infill. Use as many perimeters you need to fill up the walls of the speaker. 
2. Make sure it fits before going further. It shouldn’t be any issues though, so you can skip this step if you are a daredevil. 
3. Add the heat set inserts to the speaker standoffs. You could also cold screw the screws in to the plastic without heat set inserts, but that wouldn’t allow for a tight screwing.
4. Fasten the speaker elements with screws. Here you have to tighten as much as you can but don’t tighten too much!
5. To make the elements extra secure, add some hot glue on the sides of the speakers. It is well known that any life hack needs more hot glue.
6. Solder the wire to the terminals of the speaker element. Make sure to connect the speaker elements in series too. This will double the speaker impedance to 8 Ω, a fitting number for the design.
7. Cut a small hole in the middle of the acoustic wool and thread the wire through it. This makes the later steps much easier.
8. If you also decide to use the same colour on your banana plugs, mark up the plus and minus with a sharpie to avoid having to guess later. You don’t want to invert the sound!
9. Solder the speaker wire to the correct banana plug, otherwise you will trick yourself every time you play. You don’t want to live a life of lies.
10. Pack the acoustic wool in to the bottom of the speaker and take an extra look on the wiring of the speakers. Assert that you have some tight solder joints.
11. Place the front of the speaker in the back case. Be careful with the cables, you don’t want them to get loose now. Even if you can’t see it, try to lay the cable down in a nice way.
12. Glue the front in place with hot glue. For optimal sound the enclosure has to be air tight, so be generous during application.
13. The speakers are now done, connect them to a bluetooth amplifier and you are golden!

Enjoy the music!