Got a pair built to ship to a customer...
Customized with double leads, 3 spiders, and a Nightshade cone.
Specs as follows with a few minutes break-in :
RE: 1.84 ohms
FS: 37.87 Hz
Qes: 0.531
Qms: 7.56
Qts: 0.496
Le: 1.30 mH
Vas: 45.9 L
BL: 16.73 NA
Cms: 52.21 uM/N
Mms: 338 grams
Sens: 88.56 1w/1m
NS cone + Double leads add about 80 grams MMS compared to the Z v.2 cone with single leads.
The added mass got the Fs down and Qts up a bit -- which will be quite suitable for the 4th order band-pass the customer wants to use.