After making several textile loudspeaker versions I tested all of them in this little setup:
-Adafruit Audio FX Mini Sound Board - WAV/OGG Trigger - 2MB Flash
-Adafruit Mono 2.5W Class D Audio Amplifier - PAM8302
-strong neodym magnet
-LiPo-battery to power soundboard and amplifier
-various hollow bodies to test acoustics
The material of the speaker are in order of appearance in the video:
1. coated woven fabric, coppertape self adhesive
2. coated woven fabric, stitched copper wire
3. double layerd woven fabric, conductive yarn glued in between
4. stiff woven fabric, stitched copper wire
5. coated woven fabric, stitched conductive yarn
I tested some diffrent postures and hollow bodies with this speaker coil (coated woven fabric, stitched copper wire)
1. moving the speakercoil over the magnet and back
2. magnet on top of coil
3. little carton cap + magnet on top inside wooden cap
4. wooden cap --> this sound is very nice
5. big carton box closed, magnet on top --> sound gets lost
6. wooden box open, magnet on top of coil --> sound is very good, clear
7. big carton box closed, magnet on top of coil --> acoutic is has an hollow effect
8. big carton cap, magnet inside --> first the board acts strange, then sound is pretty clear