Frequency Response - JBL VTX A12 User Manual

10 - 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 A12 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 mentioned 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 A12 arrays using the standard VTX A12 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 pa-
rameters is necessary 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 specifically 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 shorten-
ing the length of an array works.
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 8-cabinet A12 array
Frequency response of a 6-cabinet A12 array
Frequency response of a 4-cabinet A12 array
20000
Frequency response of a 12-cabinet A12 array
Frequency response of a 12-cabinet A12 array us-
ing the 80Hz preset
20000
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