Frequency Response - JBL VTX Series User Manual

12 - FREQUENCY RESPONSE

The frequency response of a line array is determined by many factors, including the array size (number of cabinets), array curvature
(cabinet-to-cabinet angles) and the listening distance. JBL factory presets are designed to create a well-balanced tonal starting point
for a given set of array conditions. For example, the standard VTX A8 array presets are designed to work optimally with arrays of 8-12
cabinets and equal impact spacing for a flat listening plane. An array with these parameters generates a flat HF frequency response with
a gradual increase in LF energy. The frequency at which the response starts rising depends on the array parameters mentioned above.
A relatively short array will start rising lower in frequency, while a longer array starts rising at a higher frequency. Below are frequency
response examples of A8 arrays using the standard VTX A8 presets and no additional equalization/correction (flat).
20
10
0
-10
-20
20 100
20
10
0
-10
-20
20 100
Since the 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 JBL Line Array Control Panel. The Array Size Compensation Filter was specif-
ically designed to compensate for LF/MF buildup with a single, adjustable parameter. Lowering the gain value of this filter shifts lower
the frequency at which LF response starts rising— similar to the behavior when array length is shortened.
Example 1 : A8 Frequency response vs number of cabinets
1000 10000
Frequency (Hz)
Example 2: Standard preset vs 80 Hz preset
1000 10000
Frequency (Hz)
VTX A8 | User Manual
Frequency response of a 12-cabinet A8 array
Frequency response of an eight-cabinet A8 array
Frequency response of a six-cabinet A8 array
Frequency response of a four-cabinet A8 array
20000
Frequency response of a 12-cabinet A8 array
Frequency response of a 12-cabinet A8 array using the 80
Hz preset
20000
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