Subwoofers; General Guidelines For The Use Of Subwoofers - L-Acoustics dV-DOSC Operator's Manual

3.4 SUBWOOFERS

dV-DOSC is capable of radiating frequencies down to 80 Hz with good vertical directivity control (the
low frequency pattern control limit depends on the size of the array). To extend low frequency
response to 40 Hz, dV-SUB enclosures are added to create a 3-way system. SB118 or SB218
subwoofers can also be added to further extend frequency response down to 27 Hz and increase the
overall unweighted SPL. Techniques for maximizing 3-way system performance and the combined
response of dV-SUB and SB subwoofers for 4-way operation are discussed in the following along with
subwoofer arraying techniques. Please refer to Section 1.16 for details on sub/low preset processing.

General Guidelines for the Use of Subwoofers

The number of subwoofers required depends on 3 parameters:
Number of dV-DOSC Enclosures:
3-way system operation – standard subwoofer ratios:
3 dV-DOSC : 1 dV-SUB
3 dV-DOSC : 1 SB218
3 dV-DOSC : 2 SB118
4-way system operation:
3 dV-DOSC : 1 dV-SUB : 1 SB218 (normal)
3 dV-DOSC : 1 dV-SUB : 2 SB118 (normal)
♦ Type of Program Material, Desired Sub/Low Frequency Contour:
For speech reinforcement or classical music, a 6:1 dV-DOSC:dV-SUB ratio will provide nominally
flat frequency response.
When operated as a 3-way system, standard subwoofer ratios provide a 6 dB low frequency
contour and the subwoofers act as a low frequency extension for dV-DOSC. Such a low
frequency contour can be suitable for sound reinforcement of pop music or corporate events.
For more demanding music program material (rock, rap, techno etc), SB218 or SB118 subwoofers
should be added and the system operated in 4-way mode to provide a more suitable low
frequency contour.
♦ Type of Installation:
Recommended quantities remain standard when the system is ground stacked. When dV-SUBs are
flown with dV-DOSC as a low frequency extension, additional ground stacked subwoofers are
required (see below – hybrid flown/stacked subwoofers).
For 4-way system operation, two cases can be considered depending on FOH mix engineer
preference and the intended purpose of the subwoofers. For some applications, subwoofers are used
as an effect and are not driven with the same signal as the dV-DOSC/dV-SUB system (separate
auxiliary send). The other option is to use subwoofers as a low frequency extension of the dV-
DOSC/dV-SUB array and drive subs with the same signal (4-way mode). INFRA and X presets will
function with aux sub drive or in 4-way mode, however, the user should be aware of the operating
bandwidths and select the preset that is most appropriate for the installed configuration.
Subwoofers as a Low Frequency Extension
Subwoofers are driven in 4-way mode with the same signal sent to the dV-DOSC /dV-SUB array.
All 5+1 presets are optimized for 4-way system drive via input A
Input A / Outputs 1,2,3,4 = SB218 or SB118, dV-SUB, dV-DOSC LO, dV-DOSC HI
Subwoofers as an Effect
Subwoofers are driven using a separate aux send, independent from the signal sent to the dV-
DOSC/dV-SUB array.
All 5+1 format presets allow aux sub drive using input B / output 6
Input A / Outputs 2,3,4 = dV-SUB, dV-DOSC LO, dV-DOSC HI
Input B / Output 6= SB218 or SB118
Please refer to the preset setup sheets in Tables 16-19 when patching your signal distribution system.
dV-DOSC dV-SUB Manual V3.0
6 dV-DOSC : 2 dV-SUB :3 SB218 (extra)
6 dV-DOSC : 2 dV-SUB :6 SB118 (extra)
June 2005
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