JBL VLA901Hi VLA White Paper - Page 11

End-Zone Systems

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Figure 8: Retractable-Roof Stadium - two Side arrays and one End array shown Some JBL fills speakers that were used for the upper seating areas can be seen in the photo. Everything from Control Contractor to PD5000-series was used for fills of various sorts. End-Zone Systems End-zone systems have several challenges that can be met by JBL VLA SERIES arrays. Criteria include: 1. SPL levels of (105 to 110 dBA continuous long term) at throw distances of up to 750 feet. 2. Ability to overcome air loss. For example, air loss at a distance of 700 feet and 40% relative humidity is approximately 14dB in the 4000Hz band. 3. Narrow projection to reach far end of stadium while maintaining adequately low levels at the near seating. Tight vertical coverage is needed to keep energy off the field and near end zone seating. Controlled horizontal pattern is required to prevent excessive levels in the near half of the stadium. Although standard line arrays can address the first two problems - if enough are used - the third is not possible, compromising the solution. Here, a relatively narrow horizontal pattern is desirable to provide evenness of coverage. 10

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Figure 8: Retractable-Roof Stadium - two Side arrays and one End array shown
Some JBL fills speakers that were used for the upper seating areas can be seen in the photo.
Everything from Control Contractor to PD5000-series was used for fills of various sorts.
End-Zone Systems
End-zone systems have several challenges that can be met by JBL VLA SERIES arrays.
Criteria include:
1. SPL levels of (105 to 110 dBA continuous long term) at throw distances
of up to 750 feet.
2. Ability to overcome air loss. For example, air loss at a distance of 700 feet and 40%
relative humidity is approximately 14dB in the 4000Hz band.
3. Narrow projection to reach far end of stadium while maintaining adequately low levels
at the near seating. Tight vertical coverage is needed to keep energy off the field and
near end zone seating. Controlled horizontal pattern is required to prevent excessive
levels in the near half of the stadium.
Although standard line arrays can address the first two problems – if enough are used – the
third is not possible, compromising the solution. Here, a relatively narrow horizontal pattern is
desirable to provide evenness of coverage.