Here some videos of what the speaker sounds like:
Here some links to further documentation and variations of the fabric/paper speaker coil and membrane:
>> Fabric speakers
>> Paper speakers
>> Embroidered speaker kit
>> Embroidered speaker kit page
Step 1: UNDERSTANDING HOW A SPEAKER WORKS
Take a good look at the diagram and stencil on the other side of this sheet so that you understand what variables will influence the efficiency (volume) of your speaker coil before designing your own.