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VTX A8 | User Manual
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 will shift the
LF rising point lower in frequency — similar to how shortening the length of an array works.
Frequency response of a 12-cabinet A8 array
Frequency response of a 12-cabinet A8 array using the
80Hz preset
20 100 1000 10000 20000
Frequency (Hz)
-20
-10
0
10
20
SPL (dB)
11 - FREQUENCY RESPONSE
The frequency response of a line array is determined by many factors, including the array size (number of boxes), array curvature (box-
to-box angles) and the listening distance. JBL factory presets are designed to create a well-balanced tonal starting point for given array
conditions. For example, the standard VTX A8 array presets are designed to work optimally with array sizes between 8 - 12 cabinets
and equal impact spacing for a flat listening plane. An array with these parameters will generate a flat frequency response in the HF
region with a gradual rise in LF energy. The frequency point where the response starts rising depends on the array parameters men-
tioned above. A relatively short array will start rising lower in frequency, and a longer array will start rising higher in frequency. Below are
frequency response examples of A8 arrays using the standard VTX A8 presets and no additional equalization/correction (flat).
20 100 1000 10000 20000
Frequency (Hz)
-20
-10
0
10
20
SPL (dB)
Frequency response of a 12-cabinet A8 array
Frequency response of an 8-cabinet A8 array
Frequency response of a 6-cabinet A8 array
Frequency response of a 4-cabinet A8 array
Example 1 : A8 Frequency response vs number of cabinets
Example 2: Standard preset vs 80 preset
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