Handbook for Sound Engineers

Loudspeakers 621

country through much of the 1970s and is still in
common use in installed sound systems.
Recent developments in DSP technology, combined
with the constant pressure on the touring concert rein-
forcement industry to minimize weight, blockage of
audience sight lines by speakers, and truck space, have
resulted in a resurgence of interest in line arrays. As
attractive as some of their perceived performance char-

acteristics may be, they have inherent limitations. First,

the directivity attributes associated with line arrays are

present in the vertical plane (along the length of the

array) only. The horizontal directivity is only as good as

the horizontal performance of the individual devices

used to form the array. Secondly, line arrays invariably

comprise discrete elements, as opposed to a continuous

line source. This periodicity exacerbates problems with

Figure 17-44. Generic two-way loudspeaker directivity balloon and polar pattern in the crossover region.

Figure 17-45. Coaxial two-way loudspeaker directivity balloon and polar pattern in the crossover region.

Down

UpLeft Right

Re on-axis Back

Front

Re on-axis

Front

Left

Up

Down

Right

Up

Left

Re on-axis Back

Front

Re on-axis

Front

Left

Up