L-Acoustics dV-DOSC, Operator'S Manual

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dV-DOSC dV-SUB Manual V3.0 June 2005
70
Output Data
In the columns adjacent to where angle values are entered, the site angles (i.e., what you would
measure if you put a digital inclinometer on each enclosure) and the wavepath (throw distance) for
each enclosure are tabulated.
Note: The site angle for enclosure #1 is equal to the dV-BUMP or dV-BUMP2 site angle provided that the
3.75 degree angle is selected for the top dV-DOSC enclosure.
Also tabulated are continuous A-weighted SPL estimates throughout the coverage of the array on an
enclosure-by-enclosure basis. These dBA estimates are derived using a Fresnel-type calculation with a
2 kHz reference frequency for a +4 dBu nominal input signal level. Since the dBA calculation
considers discrete dV-DOSC enclosures (not sections of the continuous radiating line source) the
resolution of this calculation is not sufficient for the user to attempt to design for constant dBA
throughout the audience area. Users are advised to refer to the visual spacing between audience
impacts and use the dBA estimates as a guideline only.
In ARRAY GEOMETRICAL DATA cells, the physical dimensions of the array are displayed including:
the Overall Depth of the Array (in the x dimension), the Overall Height of the Array (in the z
dimension), and the Bottom Enclosure Elevation (front corner of the bottom enclosure, referenced to
floor level). The bottom enclosure elevation is used as a reference for installing the system and the
Depth/Height information is useful to determine if the array will physically fit in a given space (scaffold
bay, clearance to proscenium wall etc). Please see Figure 45 for further details.
ACOUSTICAL PREDICTION data gives the unweighted SPL of the array at a user-selected distance
(enter the distance in the black cell). This calculation is based on a 200 Hz reference frequency and
correlates well with the unweighted SPL (as opposed to the A-weighted enclosure-by-enclosure SPL
estimate). The peak unweighted SPL for a single array as well as an estimate of the peak unweighted
SPL for 2 arrays is also given.
Note: Unweighted SPL estimates do not include additional contributions due to subwoofers.
The Nominal Vertical Coverage Angle of the array is calculated as the sum of the entered inter-
enclosure angles. This coverage becomes effective at F
1
and for all frequencies higher than F
1
, the
vertical coverage angle is less than this nominal vertical coverage angle. Above F
2
, the vertical coverage
angle perfectly matches the nominal value. Some beaming (vertical coverage narrowing) may occur at
F
3
, especially when the array is of constant curvature type.
Finally, MECHANICAL DATA gives an estimate as to the rear versus front motor load distribution and
the stress on the front and rear dV-PINS used to attach the top dV-DOSC to dV-BUMP or dV-
BUMP2. These load distributions depend on the size and shape of the array as well as the array site
angle (equal to Site #1) which, in turn, affect the location of the centre of gravity.
Important things to note:
1) ARRAY WEIGHT includes dV-DOSC enclosures, the dV-BUMP bumper and dV-ANGLE, dV-PIN
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) Rear and Front Pin Stress refer to the stress on the dV-PINs used to attach the top dV-DOSC
enclosure to dV-BUMP or dV-BUMP2 and is accurate within 20% error.