L-Acoustics dV-DOSC Operator's Manual page 76

(xiii) Pre-attach two more dV-ANGLE bars at desired angle (xiv) Stack the second dV-DOSC enclosure
(xv) Pin front points first, rear points last using dV-PIN25
(xvi) Use dV-ANGLE at 3.75 (rear) and 7.5 (front) degree positions as
a site for adjusting the focus of the stacked system
dV-DOSC dV-SUB Manual V2.0 Nov 2001 76