In case anyone wanted to know, because it doesn't seem to be in the spec sheet, I took apart a ND25TA tweeter. The magnetic gap is 2mm, the voice coil is either 1mm (top layer) or 1.3mm(bottom layer). Thus Xmax is 1mm or 0.7mm (p-p).
The VC uses 0.13mm wire. It is double layer with 10 windings on the bottom and 8 windings on top.
The VC uses 0.13mm wire. It is double layer with 10 windings on the bottom and 8 windings on top.