Martin Audio W8L Specifications download pdf (Page 19)

Unfortunately, the line array effect can also be limited by other factors:

Real-world arrays tend to be acoustically small at low frequencies – restricting

the low attenuation region to just a few metres

Air absorption can cause excess attenuation of high frequencies and can be a

significant factor over medium to long distances as it has a linear dB

characteristic with distance (i.e. it may be quantified in dB/m)

Coupling between adjacent elements can be imperfect at high frequencies

because cabinet to cabinet spacing is significant at very short wavelengths. This

is minimised for W8L Series systems by placing the cabinet-to-cabinet hinge at

the front.

W8L Series

Note that our mid and hf designs do not try to emulate a dead straight ribbon. Practical

loudspeaker columns must have vertical coverage patterns tailored to suit the audience

size and shape and our line array systems have been designed with this in mind. The W8L

Series are deliberately designed to produce slightly curved vertical wavefronts - enough to

allow up to 7.5

of vertical splay to be introduced between boxes but not enough to affect

straight line performance.

Curved arrays – determining inter-cabinet splay angles

Straight columns (0º splay angles) produce far-field high-mid frequency sound pressure

levels that increase approximately 6dB for every doubling of W8L quantities but, as inter-

box splay angles increase, the vector sum of multiple W8Ls decreases through 3dB for a

3º splay to 0dB (no summation) at 7.5

. This Progressive Curvature provides smooth

level coverage without amplifier channel trimming for most applications.

ViewPoint™ and DISPLAY™ software

Martin Audio’s ViewPoint and DISPLAY software calculates the optimum progressive

curvature for a given audience area. The progressive curvature produces a more consistent

frequency response from the front rows to the rear seats than the commonly used J-shaped

arrays that have a straight, long throw section at the top and a curved lower section. An

over-angular J-shaped array acts like a foreshortened straight array above a point source

array and creates vertical lobes that result in irregular coverage.

ViewPoint calculates the maximum summation point (near the top of a progressively

curved array) and aims this towards the furthest listening area. A progressive curvature

array’s HF coverage weakens dramatically above the maximum summation point so this

point is regarded as the Coverage Stop.

ViewPoint simply advises on the appropriate array geometry and controller presets for a

given 2-D room geometry. DISPLAY™ operates may be used in 2-D or 3-D and predicts

polar responses, coverage levels and frequency responses.

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Martin Audio W8L Specifications Page 19