JBL VTX B18 Series, Руководство пользователя

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VTX B
18 | User Manual
13 - ELECTRONIC DELAY STEERING (EDS)
When constructing large horizontal subwoofer arrays, the overall size of an array can have a negative impact on the subwoofer cover-
age. The longer the array, the narrower the coverage. Electronic Delay Steering (EDS) is a technique used to alter the coverage angle of
a given subwoofer array by applying a specific, pre-calculated delay value to each subwoofer enclosure. The goal of EDS is to electron-
ically alter the shape of a subwoofer array and widen the coverage pattern by creating a virtual arc. The radius of the arc controls the
radiating pattern of the array and each delay value is carefully calculated to align all subwoofers to the virtual arc. Hybrid cardioid EDS
subwoofer arrays provide even horizontal coverage with 15—25 dB broadband SPL rejection behind the array.
13.1 - EDS EXAMPLE - NO DELAYS
The example below shows the unaltered coverage of a horizontally distributed array of B18 subwoofers. Each B18 cluster, consists of
three B18 enclosures with the bottom B18 facing backwards to create a 2:1 cardioid configuration. The center-to-center spacing of the
array was calculated at 2.5m (8.2’) which makes the total length of the array 18.3m (60’) long. Given the overall large size of the array,
the array directivity increases, reducing the coverage to the center of the venue. The SPL Mapping below, was generated in LAC-3, and
demonstrate the coverage of this array at 50Hz.
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B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN
B 18
Compact Single 18” Subwoofer
IN/OUT IN/OUT
A B
Channel Selection
SN