JBL VTX A12, Руководство пользователя

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VTX A12
| User Manual
21
9.4 - TIME ALIGNMENT
The VTX A12 presets provide proper system summation with companion VTX subwoofers under physically coupled
configurations (stacked or suspended) and when used with corresponding G28 and S28 presets. This pre-alignment
is done at the factory, allowing any VTX subwoofer to be used with any VTX loudspeaker without needing specific sub-
woofer presets for each system and configuration. When the VTX A12 is operated in full range mode with companion
subwoofers, some additional delay should be applied to the subwoofers to match the A12.
Additional time alignment delay should be added, as necessary, to account for physical path length differences between
suspended A12 arrays and ground-stacked G28 or S28 subwoofers. If no acoustic measurement system is available,
delay values can be calculated based on the geometric path difference between a reference point (i.e. FOH position)
and each system. This is an effective method since all VTX presets include a factory pre-delay to correctly align all com-
ponents. This method is not effective and should not be used when the latency of a system is unknown, such as when
different parts of the system follow a different signal path that might affect latency.
dSub
dSub
dFlown Ar
ray
Path Diff
A12 VTX
G28
VTX
S28
VTX
Path Difference =
dFlown Array - dSub
Sub Delay =
Path Difference (meters)
343 (meters / second)
Sub Delay =
Path Difference (feet)
1140 (feet / second)
or