L-Acoustics ARCS, Руководство оператора

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L-ACOUSTICS ARCS Manual V2.0 2/13/2003
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4.6 USING ARCS WITH SUBWOOFERS
For music applications, ARCS should be used with SB218 or dV-SUB subwoofers while for speech,
ARCS can be operated full range in 2-way mode and subwoofers are not necessary. As a guideline,
typically one SB218 or dV-SUB subwoofer per pair of ARCS will provide sufficient output (2:1
ARCS:Subwoofer ratio). Issues involved in effectively using ARCS with subwoofers are discussed
below and as a reference, L-ACOUSTICS subwoofer specifications are summarized in Table 10 and
Fig 14.
Table 10: L-ACOUSTICS Subwoofer Specification Summary
L-ACOUSTICS Freq Resp Usable LF Sensitivity RMS POWER POWER MAX SPL MAX SPL REC'D LOAD
SUB MODEL (+/- 3 dB) (-10 dB) (1W / 1m) Voltage (cont) (peak) (cont) (peak) AMP (ohms)
SB115 45 - 100 Hz 40 Hz 94 45 250 W 1000 W 120 dB 126 dB 500 W 8
SB118 35 - 100 Hz 32 Hz 97 70 600 W 2400 W 125 dB 131 dB 1200 W 8
SB218 28 - 140 Hz 25 Hz 100.5 68 1100 W 4400 W 130 dB 136 dB 2200 W 4
dV-SUB 40 - 200 Hz 35 Hz 104.5 57 1200 W 4800 W 133 dB 139 dB 2400 W 2.7
90.0
92.0
94.0
96.0
98.0
100.0
102.0
104.0
106.0
108.0
110.0
112.0
114.0
116.0
118.0
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
10 100 1000 10000
frequency (Hz)
dB SP
L C
onti
nuous
r
e
: one
s
our
c
e
SB118
SB115
dV-SUB
SB218
Figure 20: L-ACOUSTICS Subwoofer Continuous Unweighted SPL Comparison
a) Combining ARCS With Subwoofers
In this section, we present techniques for optimizing the coupling between an ARCS array and
subwoofers. Two cases can be considered: ground stacked systems where ARCS and subwoofers are
closely coupled; and a separate flown ARCS array with ground stacked subwoofers. For both cases,
processing will depend on the intended purpose of the subwoofers, i.e., in some applications,
subwoofers are used as an effect and are not driven with the same signal as the main ARCS system
(separate auxiliary send from the console) while in other cases, the subwoofers are used as a low
frequency extension of the array and are driven with the same signal in 3-way mode.
An ARCS array is capable of radiating frequencies down to 40 Hz at high level and for standard 2W
presets a 40 Hz, 24 dB per octave slope Linkwitz Riley (LR24) high pass filter is employed with
additional low frequency shelving equalization. When adding subwoofers to the system, part of the
frequency range can overlap resulting in the potential for interference due to the phase shift of
overlapping crossover filters (depending on the selected preset and how the subwoofers are driven).