Electronic Delay Steering (Eds); Eds Example - No Delays - JBL VTX Series User Manual

13 - ELECTRONIC DELA Y STEERING (EDS)
The longer a loudspeaker array is, the narrower the coverage it provides. When a large horizontal subwoofer array is used, its overall size
can negatively impact its coverage. Electronic Delay Steering (EDS) is a technique used to electronically widen the coverage pattern of
a subwoofer array into a virtual arc by applying a specific, precalculated delay value, based on the radius of the arc, to each subwoofer
enclosure. EDS-enhanced cardioid subwoofer arrays provide even horizontal coverage with 15—25 dB of broadband SPL rejection
behind the array.
13.1 EDS EXAMPLE - NO DELA YS
The figure below shows the unaltered coverage of a horizontally distributed array of B18 subwoofers. Each 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 is
calculated at 2.5 m (8.2 ft), making the total length of the array across all cabinets 18.3 m (60 ft) from the array's leftmost cabinet edge
to its rightmost edge. The large size of the array increases its directivity, reducing coverage in the center of the venue. The SPL Mapping
below, generated in LAC-3, demonstrates the array's coverage at 50 Hz.
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0
0 4 8 12 16
B18 B18
Compact Single 18" Subwoofer Compact Single 18" Subwoofer
IN/OUT IN/OUT IN/OUT IN/OUT
A B SN A B SN
Channel Selection Channel Selection
20 24 28 32 36 40
B18
Compact Single 18" Subwoofer
IN/OUT IN/OUT
A B SN
Channel Selection
44 48 52 56 60
B18 B18
Compact Single 18" Subwoofer Compact Single 18" Subwoofer
IN/OUT IN/OUT IN/OUT IN/OUT
A B SN A B SN
Channel Selection Channel Selection
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VTX B18 | User Manual
64 68 72 76 80
B18 B18
Compact Single 18" Subwoofer Compact Single 18" Subwoofer
IN/OUT IN/OUT IN/OUT IN/OUT
A B SN A B SN
Channel Selection Channel Selection
140
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105
100
84 88
B18
Compact Single 18" Subwoofer
IN/OUT IN/OUT
A B SN
Channel Selection