Cardioid Configurations - JBL VTX Series User Manual

11 - CARDIOID CONFIGURA TIONS
The directivity of a subwoofer is understood to be omnidirectional, meaning energy is produced equally in all directions. In reality, most
subwoofers do exhibit some front-to-back directivity (about 1-3 dB, depending on the frequency) but not enough to have any meaning-
ful impact. In some cases, the omnidirectional nature of subwoofers is desirable, but in other situations, more controlled (directional)
coverage is appropriate. The most common use for directional subwoofer arrays is to reduce the amount of low-frequency energy on-
stage. Two other typical uses are to avoid putting excessive low-frequency energy into a room or to control noise pollution in outdoor
concerts situated near residential areas.
A single VTX B18 cabinet radiates omnidirectionally, but cardioid coverage can be achieved by a B18 array in which the physical orien-
tation of some cabinets is reversed and an appropriate amplifier preset selected.
B18
Compact Single 18" Subwoof er
IN/OUT IN/OUT
A B SN
Channel Selec tion
Example 1 : Three VTX B18s in omni-directional mode (forward facing)
Example 2 : Three VTX B18s in cardioid mode (front-rear-front)
VTX B18 | User Manual
Vertical
25
80Hz
Horizontal