High directivity over a broad frequency range allows the sound to be focused
on the audience area, keeping the sound off the ceiling, the wall behind the
audience and the areas above, behind and below the array. Due to its high
directivity, the array excites the reverberant field less and the overall
noise decreases in the space. Since there is less overall noise in the space
because reverberation is decreased, line arrays tend to be very intelligible
in difficult spaces.
Line arrays attenuate at 3dB per doubling of distance in the far field, as
compared with a point source speaker's typical attenuation of 6dB per doubling
of distance. Consequently, arrays have uniform sound coverage from the front
of the room to the back of the room. Line arrays can propagate sound over large
distances with low distortion. That means a point source speaker that is 110dB
at the source will be 86dB at 16 meters while the line array will be 98dB. In
16 meters (52ft.) there is a difference of 12dB or perceived as about twice as
loud.
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