L-Acoustics V-DOSC, Operator'S Manual

Page: 100 / 158

L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 100 of 158
HORIZONTAL SB218 (16 TOTAL)
T4 T3 T2 T1 T1 T2 T3 T4
T4 T3 T2 T1 T1 T2 T3 T4
T1 = 0 msec
T2 = 1.167 msec
T3 = 3.036 msec
T4 = 5.495 msec
VERTICAL SB218 (8 TOTAL)
T4 T3 T2 T1 T1 T2 T3 T4
T1 = 0 msec
T2 = 0.493 msec
T3 = 1.282 msec
T4 = 2.320 msec
HORIZONTAL SB218 (24 TOTAL)
T6 T5 T4 T3 T2 T1 T1 T2 T3 T4 T5 T6
T6 T5 T4 T3 T2 T1 T1 T2 T3 T4 T5 T6
T1 = 0 msec
T2 = 0.761 msec
T3 = 2.052 msec
T4 = 3.863 msec
T5 = 6.088 msec
T6 = 8.634 msec
VERTICAL SB218 (12 TOTAL)
T6 T5 T4 T3 T2 T1 T1 T2 T3 T4 T5 T6
T1 = 0 msec
T2 = 0.322 msec
T3 = 0.867 msec
T4 = 1.632 msec
T5 = 2.572 msec
T6 = 3.649 msec
Figure 77: Electronic delay processing examples using a 4- or 6-channel DSP
3.5.3 LEFT/CENTRE/RIGHT CONFIGURATIONS
LCR subwoofer arrays are of interest for many of the same reasons as LCR V-DOSC arrays (see
Section 3.2.2). When properly time aligned, the LCR configuration can provide more even low
frequency impact and horizontal coverage combined with reduced centre build up in comparison with
L/R subwoofer arrays. In effect, LCR subwoofer arrays act as an approximation to an electronic delay
processed horizontal line array of subwoofers as discussed in Section 3.5.2.
Figure 78(a) shows a ground stacked LCR configuration. In this case, time alignment should be
performed in multiple steps: (i) time align L with respect to C with the measurement microphone on-
axis to L at a distance where the SPL from C and L arrays is identical; (ii) time align V-DOSC FOH L
with respect to L with the measurement microphone located between FOH L and ground stacked L
subwoofers at a distance where the SPL from the low section of the flown system equals the SPL from
the ground stacked subwoofers; (iii) duplicate the time alignment settings for R subwoofers and FOH
R; (iv) if applicable, time align LL and RR to L and R, respectively, using a measurement location in a
representative location where the coverage of the main and off-stage fill systems overlap.
Figure 78(b) shows a hybrid ground stacked LR / flown C configuration. In this case, a stereo infill
system (using ARCS or dV-DOSC, for example) can be combined with the ground stacked LR
subwoofer arrays and a centre cluster fill system could be integrated with C subwoofer array. Time
alignment should be performed in multiple steps: (i) time align L with respect to C with the
measurement microphone in between L and C at a distance where the SPL from C and L arrays is
identical; (ii) time align V-DOSC FOH L with respect to L with the measurement microphone located
between FOH L and ground stacked L subwoofers at a distance where the SPL from the low section
of the flown system equals the SPL from the ground stacked subwoofers; (iii) duplicate the time
alignment settings for R subwoofers and FOH R; (iv) if applicable, time align LL and RR to L and R,
respectively, using a measurement location in a representative location where the coverage of the
main and off-stage fill systems overlap.
Figures 78 (c-f) show various hybrid flown LR / ground stacked C configurations. Figure 78 (c) shows
a central ground stacked C position, (d) shows a L/R ground stacked C position which also functions as
part of a stereo infill system; (e) shows a central subwoofer line array with electronic delay processing;
(f) shows a distributed ground stack subwoofer configuration which can also be used with electronic
delay processing. For all of these configurations, a time alignment procedure similar to what is
recommended for figure 78 (c) should be employed.