user manual portable speaker VRX900

AMPLITUDE SHADING

Amplitude Shading

Amplitude shading is a technique that allows the coverage pattern of a loudspeaker array to be shaped by

adjusting the relative acoustic output of some of the devices in the array. Most often, array shading involves

only the mid and high-frequency sections of the array. In a simple system consisting of three

VRX932LA/VRX928LAs, the lower speaker (which covers the nearest listeners) may have its high-frequency

output reduced. At the same time, the upper speaker may have its high frequency output increased. The overall

sound-power in the room is unchanged but the distribution of acoustic energy to the audience is far more

uniform. Amplitude shading of a VRX932LA/VRX928LA array may be accomplished in passive or bi-amplified

systems.

Array Configuration Selector (ACS)

In passive mode, the Array Configuration Selector may be used. The -3 dB position will typically be used for

the speaker(s) in an array that are covering the nearest listening area. The +3 dB position will be used for the

speaker(s) covering the more distant areas; or to compensate for the low-frequency build-up resulting from

mutual coupling of multiple woofers in an array.

Short Throw (-3 dB)

Long Throw (+3 dB)

Medium Throw (0 dB)

Frequency Response

The frequency response graph represents measurements from a single typical VRX900LA speaker, applying the

three different ACS settings: +3dB, 0dB, -3dB.