Frequency Response - JBL VTX Series User Manual

11 - FREQUENCY RESPONSE

The frequency response of a line array is determined by many factors, including the array size (number of boxes), array curvature (cab-
inet-to-cabinet angles) and listening distance. JBL factory presets are designed to create a well-balanced tonal starting point for given
array conditions. For example, the standard array presets are designed to work optimally with array sizes between eight and 12 cabinets
and equal impact spacing for a flat listening plane. An array with these parameters generates a flat HF frequency response with a grad-
ual rise in LF energy. The frequency at which the response starts rising depends on the array parameters mentioned above. A relatively
short array starts rising at a lower frequency than a longer array. Below are examples of the frequency responses of A12 arrays using the
standard VTX A12 presets with no additional equalization/correction (flat).
20
10
0
-10
-20
20 100
20
10
0
-10
-20
20 100
Since a factory preset cannot account for all variables and array configurations, user adjustment of certain DSP parameters is neces-
sary to achieve the desired tonal balance for a given array and application. The LF response of any VTX line array system can be easily
adjusted using the Array Size Compensation Filter in the Line Array Control Panel. The Array Size Compensation Filter was specifically
designed to compensate for LF/MF buildup with a single, adjustable parameter. Lowering the gain value of this filter shifts down the
frequency at which LF response starts rising — similar to shortening the length of an array.
Example 1 : A12 Frequency response vs number of cabinets
1000 10000
Frequency (Hz)
Example 2: Standard preset vs 80 preset
1000 10000
Frequency (Hz)
VTX A12 | User Manual
Frequency response of a 12-cabinet A12 array
Frequency response of an eight-cabinet A12 array
Frequency response of a six-cabinet A12 array
Frequency response of a four-cabinet A12 array
20000
Frequency response of a 12-cabinet A12 array
Frequency response of a 12-cabinet A12 array using the
80 Hz preset
20000
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