Fully functional DIY Speaker Driver (10mm magnet)

What's so special about this model?
You can build your own funcional speaker. Not the speaker box, but the speaker driver itself! So this model will actually be a sound source generating sound.

What do I need?
The model includes the frame, diaphragm and suspension of the speaker. It consists of two parts that can be glued together or screwed together (3x M3x6mm).
All you need in addition is a magnet, some insulated copper wire and an M8x12mm screw or M8 threaded rod.

Printing and post processing
Both parts are easy to print and don't need any support structures! I recommend 0.2mm layerheight. You can use a brim to get better adhesion. PETG and PLA will work, but PLA may give you better overhangs. After printing all you need to do is cut the M8 threaded hole open. (It's closed by one layer so it prints without support.)

The magnet
A 10mm thick neodym magnet with a diameter of 20mm will work well. But you can also stack thinner magnets or (to some extend) use smaller diameters.

Winding the coil
The voicecoil can easily be made by winding enamelled copper wire. Wire with 0,1mm - 0,2 mm diameter seems to work best. Before you start winding, secure the beginning of the wire with tape. Keep a bit of tension on the wire at all times. When you are done, use superglue to secure the windings of the coil. 

How much wire do I need?
The resistance/impedance of your speaker will depend on the wire used and it's length. I recommend you check the ratings of your amp. Most amps allow 8Ω or even 4Ω. Just stay above that value and you are fine. With 0,1mm wire you need a length of roughly 5 meters for 10Ω. With 0,2mm you will roughly need 15 meters.

A bit of soldering
It makes sense to solder the thin enamelled wire to some robust thicker wire. Use a lighter to remove 10mm coating from the enamelled wire. Then you can solder it to a thicker wire and put scrinking tube over it. (I have to admit, this is the tricky part.) When assembling, place the wire in the gap, like you see in the picture on the right. 

Assembly
Insert the M8 screw/rod in the rear part. Then attach the magnet to the srew/rod. The magnetic force is sufficient, no glue needed. Next, screw (M2x6mm) or glue the rear part of the speaker to the front part. You can adjust the exact position of the magnet later by turning the M8 screw/rod.

How do I use the speaker?
You can connect both ends of the coil (or the thicker wire soldered to it) directly to an amplifier chip like the cheap TDA2030 (costs around 2€). Technically you can also use it as a replacement for a broken speaker driver, but for obvious reasons it may not perform as well as a professional mass-manufactured speaker.

How is the sound quality?
Surprisigly good!!! In the beginning I had rattling noises with all of my prototypes. Some were caused by the wire vibrating or the screw being a tiny bit too lose and vibrating. Almost all of this can be fixed. Only one downside remains: The speaker is quiter than a purchased one. The reason probably is, that we are not using a yoke and therefore the shape of the magnetic field is not optimal.
Here is a video comparing the 3D printed speaker with a cheap purchased one. Important note: I adjusted the volumes, so one can compare the sound quality.