L-Acoustics V-DOSC, Operator'S Manual

Page: 152 / 158

L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 152 of 158
APPENDIX 6:
PATTERN CONTROL OF A CONSTANT CURVATURE ARRAY
In practice, the vertical coverage angle is controlled for frequencies greater than frequency F
1
where:
and N is the number of enclosures, A is the constant angle between enclosures in degrees.
At F
1
, the vertical coverage angle is equal to the nominal value for the array, i.e., (N-1) x A
degrees. At higher frequencies, the coverage decreases to a value which is approximately equal
to 2/3 of N x A. This defines the minimum vertical coverage angle and is termed the "beaming"
frequency F
3
. The vertical coverage angle then increases back to the nominal value at F
2
, defined
by:
For frequencies higher than F
2
, the vertical coverage angle is constant.
For example, a constant curvature array of 8 V-DOSC with 4° between all enclosures provides
constant 28° vertical coverage above F
2
= 794 Hz, with narrower coverage at F
2
= 427 Hz and
with a broadening of coverage below F
1
=230 Hz that is subject to the laws of diffraction govern
ing spherical wave propagation.
Figure 113: Illustration of the variation of vertical coverage angle with frequency






=
2
NA
sin N
444
F
1
2
5
2
AN
10 x 77 . 1
F
=