Time Alignment - JBL VTX Series User Manual

10.4 TIME ALIGNMENT

The VTX A12 presets provide proper system summation with companion VTX subwoofers in physically coupled configurations (stacked
or suspended), and when used with corresponding subwoofer presets. This pre-alignment is done at the factory, allowing any VTX sub-
woofer to be used with any VTX loudspeaker without the need for subwoofer presets specific to 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 needed to account for physical path length differences between suspended A12
arrays and ground-stacked 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 method is effective because every VTX
preset includes a factory pre-delay to correctly align all components. When the latency of a system is unknown, this method is not ef-
fective and should not be used. This can occur when the signal paths of different parts of the system vary in latency.
VTX A12
VTX A12 | User Manual
VTX B28
Path Difference
Sub Delay =
Sub Delay =
dSub
23
= dFlown Array - dSub
Path Difference (meters)
343 (meters / second)
or
Path Difference (feet)
1140 (feet / second)