JBL VTX Series, Manual

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VTX A 12 | Rigging Manual
8.4 EXTENSION BAR ATTACHMENT OPTIONS
The VTX A12 AF EB Extension Bar includes three attachment positions for connecting to the Array Frame. The three positions allow for
additional aiming resolution when an array is suspended from a single point. In single-point applications, the array aiming is determined
by the shackle position on the Extension Bar. The Extension Bar includes 20 shackle positions, which are spaced 51 mm (2 in) apart
to maintain the structural integrity of the bar. Even at 51 mm apart, the spacing is not fine enough for precise sub-degree aiming, so a
shackle position is needed between two holes. The three attachment positions (A, B and C) allow for two additional shackle positions
between holes, which increase the total number of shackle positions to 60.
A
B
C
1
2
3
4
5
6
7
8
9
10 11
12
13
14
15
16
17
18
19
20
The example below shows how the real and “virtual” positions are spaced across the extension bar.
A
B
C
B
C
A
B
C
A
TIP:
Refer to JBL Line Array Calculator 3 software to determine the best shackle position and attachment combination to
achieve the required array angle.