Electro-Voice EVA Series User Manual
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3.0 Designing an EVA Array (cont’)
3.42 A five-Module Array Example
Figure 9a shows a five-module array of EVA-2082S modules in a 100-ft-deep venue with a flat floor and a small
balcony/choir loft at the rear typical of many house-of-worship environments. The three frequencies not only track
very well but nearly all the main floor is within ± 3 dB front to back. Balcony maintains good spectral balance at a
slightly lower SPL. This desirable situation is helped by not only the 3 dB attenuation of the top element but also by
the array being longer than in the previous example (8.0 ft versus 4.7 ft). Note also the progressive attenuation of
the bottom three elements, made possible by combining an EVA-AM installed in the bottom module with the built-
in HF shading of the lower elements of the bottom two modules. To accomplish this with a typical active line array
would have required six additional channels of amplification and processing.
This venue has a ceiling height of twenty four feet, which after allowing for hoist and rigging, results in a trim height
of only twenty two feet. The excellent vertical directivity of the five module array keeps excess energy off the low
ceiling and results in improved intelligibility throughout the venue while maintaining over fourteen feet of clearance
from the floor to the bottom of the array. The customer also wants subwoofers but there is no place to put them on
the main floor. The subs will have to be flown, and will require three EVA-1151D or two EVA-2151D subwoofer
modules to acoustically balance the output of five full range modules. Figure 9b shows the five module full range
array with subs mounted in their normal position on top. This configuration results in less than nine feet of clearance
at the bottom of the array and requires extreme attenuation of the bottom modules. The front to back coverage,
while still acceptable, has been compromised by the full range array being too low to the floor. The whole array can
be shortened, but at the expense of uniform coverage as seen in the earlier examples. Figure 9c shows the ideal
solution. Three EVA-1151D subwoofer modules are flown behind the five module full range array on an EVA-CG
Coupler Grid. Coverage, trim height and ground clearance are all essentially identical to the original five module
array without subs.
Figure 9a:
A five-module EVA example whose three predicted frequencies not only track well
front-to-back, but also fall mostly within the desired ±3 dB
