Subwoofer Options; Sub/Lf Preset Options - JBL VTX Series User Manual

10 - SUBWOOFER OPTIONS

VTX A12 presets are designed for a 3:2 minimum ratio of A12 cabinets to VTX B28 or S28/G28 subwoofers. The 3:2 ratio provides suffi-
cient headroom for both the subwoofers and the A12s to reach their MAX SPL (i.e. limiter threshold) at the same time, while maintaining
a minimum of 10 dB subwoofer to full-range low frequency contour. Other ratios can be used depending on the desired tonal balance
target, MAX SPL, and application.

10.1 SUB/LF PRESET OPTIONS

As mentioned, there are two LF presets available for the A12 system: the VTX A12 (full-range) preset, which extends the frequency re-
sponse of the system down to 45 Hz, and the VTX A12 80 (80 Hz) preset, which extends the frequency response of the system down
to 80 Hz. The VTX A12 (full-range) preset is used when the system is operated without subwoofers or when the application calls for
extended LF response from the main arrays. The VTX A12 80 (80 Hz) preset is used only when subwoofers are available and the highest
A-weighted sound pressure level (SPL) is required. When multiple A12 arrays are used (e.g. main and side arrays), all A12 arrays should
be operated in the same LF mode for headroom consistency and proper summation. Subwoofers are typically set to the mode corre-
sponding to the mode selected for the A12.
Example 1: A12 80 | SUB: 80
20
10
0
-10
-20
20 100
VTX A12
1000
Frequency (Hz)
VTX A12 | User Manual
VTX B28
Example 2: A12 FR | SUB: 60/80
20
10
0
-10
-20
20 100
21
SUB: 80Hz
SUB: 60Hz
1000
Frequency (Hz)