dV-DOSC dV-SUB Manual V3.0 June 2005 52
Stereo 3-way presets are also provided for dV-DOSC plus L-ACOUSTICS SB118 (single 18'') and
SB218 (dual 18'') subwoofers. Two types of presets are provided for each subwoofer: 3W (120 Hz
crossover point) and 3WX (80 Hz crossover point). The 3W preset is intended for applications where
subwoofers are closely coupled to the dV-DOSC array as an extension of the system and 3WX
presets are intended for applications where subwoofers are ground stacked, separate from the flown
dV-DOSC arrays. SB118 3-way presets are optimized for a 3:2 dV-DOSC:SB118 cabinet ratio, while
SB218 3-way presets are optimized for a 3:1 ratio.
4-way presets are provided for flown dV-DOSC + dV-SUB arrays when used in conjunction with
ground stacked SB118 or SB218 subwoofers. Recommended ratios are 3:1:1 dV-DOSC:dV-
SUB:SB218 ratio or 3:1:2 dV-DOSC:dV-SUB:SB118. Two types of presets are available – INFRA and
X. For INFRA presets, there is a 60 Hz crossover point between SB118 or SB218 subwoofers and dV-
SUB. For X presets, the dV-SUB operating bandwidth is extended down to 30 Hz and SB118 or
SB218 subwoofers are operated from 26-80 Hz with negative polarity (to account for the phase shift
due to the overlap in their operating bandwidths).
For 5+1 format 4-way presets, separate processing is provided for flown versus ground stacked
subwoofers. For example, the dV+dVS+SB218 X LO/HI preset has the following output channel
assignments:
Output 1 SB218 ground stacked (input A)
Output 2 dV-SUB flown (input A)
Output 3 dV-DOSC low section (input A)
Output 4 dV-DOSC high section (input A)
Output 5 fullrange (input A)
Output 6 SB218 ground stacked (input B)
Note: For all 5+1 format 4-way presets, output 6 can be used for auxiliary sub drive via input B.
Note: The crossover frequency between the flown dV-SUB and dV-DOSC low section is 120 Hz to optimize
the power bandwidth for both sections for all 4-way presets.
Version 7 preset names and descriptions for Lake Contour, XTA 224, 226 and BSS 366 digital signal
processors are given below. Full details of channel assignments and user adjustable parameters are
provided in the Preset Description sheets that are distributed with PCMCIA cards. Alternatively,
preset data along with preset setup sheets can be downloaded from
www.l-acoustics.com
.
SUBWOOFER TIME ALIGNMENT RECOMMENDATIONS
For the dV-DOSC V7 release, sub/low sections are “pre-aligned” for 3-way and 4-way presets in a
closely coupled measurement configuration. This way, when dV-DOSC is flown and subs are ground
stacked all that is required is to measure the geometric/physical path difference (at your reference
point of choice) and add this to the standard pre-aligned sub delay. If using Bushnell Rangefinders to
measure the path difference, the accuracy corresponds to +/- 1 meter so the geometric starting point
can be varied by +/- 3 msec to verify optimum summation. This provides a quick and easy subwoofer
alignment technique for those who don’t have the measurement gear required to measure impulse
responses. If you have the ability to measure impulse responses, refer to the figures below for the
individual presets as a reference for time alignment. Basically, when you look at the separate impulse
responses for sub and low sections, there is a “sine wave” signature that needs to be aligned.
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