Here are some JBL 2118H parameters compiled by Drew Daniels.
It looks as if it needs to go in .5 cu ft box, vented or sealed.
I hope this helps.
NW
FS 85Hz
Qts .35
VAS .5 cu ft
Xmax .12 in
Qes .4
Qms 2.4
Re 5.5 ohms
Le .6 mH
BL 11
Mms 17 grams
DB 95.4 1w/1m
Cone diameter 6.5 in
B4 tuning .4 cu ft
FB 91.8 Hz
F3 96.1Hz