L-Acoustics V-DOSC, Operator'S Manual

Page: 72 / 158

L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 72 of 158
Important things to note:
1) ARRAY WEIGHT includes V-DOSC enclosures, the V-DOSC BUMP2 bumper and angle strap
weights only. Loudspeaker cables, steels and motor weights are not included.
2) Calculation of the REAR LOAD is within 20% error. When the rear motor load goes to zero,
Maximum Site Angle is displayed.
3) Calculation of the FRONT LOAD is within 20% error. When the front motor load goes to zero,
Minimum Site Angle is displayed.
4) 2-LEG STRESS refers to the stress on the V-DOSC BUMP2 bumper’s rotating legs and is accurate
within 20% error.
NOTE: the effect of rear ratchet straps is not taken into account.
5) 2-ANGLE STRESS refers to the stress on the top enclosure’s BUMP angle straps and is accurate
within 20% error. If the angle strap load rating is exceeded there is a WARNING indication.
Note: the
effect of additional rear ratchet strapping is not taken into account.
IF YOU ARE APPROACHING A WARNING INDICATION DO NOT OVERTIGHTEN RATCHET
STRAPS UNDER ANY CIRCUMSTANCES. USE SPACER BLOCKS INSTEAD.
For more details on ratchet strap issues, please refer to Section 4.2.
dV-ARRAY1, dV-ARRAY2 Input Data
Input data and the optimization procedures for dV-ARRAY1 and dV-ARRAY2 worksheets are the same
as for V-ARRAY1 and V-ARRAY2 except for the following differences: 1) geometric data and XZ
origins are different due to the front pivoting rigging system (see figure 49); 2) up to 24 dV-DOSC can
be simulated; 3) mechanical data refers to the stress on rear and front pins for the top enclosure to
dV-BUMP attachment (not including dV-SUB); 4) a pick point calculation utility is included for single
point hangs; 5) angular spacing between enclosures is chosen from the following available values: 0°,
2°, 3.75°, 5.5°, 7.5° for dV-ANGLEP1 or 1°, 3°, 4.5°, 6.5° for dV-ANGLEP2.
Note: The site angle for dV-DOSC enclosure #1 is equal to the dV-BUMP site angle provided that a 3.75°
angle bar is used at the rear to connect enclosure #1 to the bumper. The 3.75° angle should be used to
attach the top dV-DOSC to dV-BUMP – this allows a laser and/or remote digital inclinometer to be
mounted on the dV-BUMP to measure the focus of the top enclosure.
dV-DOSC PICK POINT UTILITY
A pick point calculation utility is also included for single point dV-DOSC array hangs. Pick point holes
are numbered 0 to 16 from front-to-rear on dV-BUMP. Hole 0 corresponds to the downstage motor
point, holes 1-8 correspond to pick points on the central spreader bar and holes 9-16 correspond to
pick points on the rear extension bar. The user varies the pick point number (from 0 to 16) and the
bumper elevation while attempting to minimize the ‘’Site Angle Deviation wrt Target’’ value so that
this value is as close to zero as possible. The user can then determine the appropriate pick point and
whether the dV-BUMP extension bar is required or not.
Note: Always verify the actual, obtained array tilt angle using an inclinometer during installation. If a 3.75
degree angle is used between the top dV-DOSC and dV-BUMP, then the angle of dV-BUMP corresponds to
‘Site #1 to Next’’ for the selected pick point.
For further details on modelling dV-DOSC using ARRAY2004, please refer to the dV-DOSC User Manual.