Jbl VRX932LA User Manual download pdf (Page 5)

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 VRX932LAs, 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

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 speak-

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

pling of multiple woofers in an array.

Short Throw (-3 dB)

Long Throw (+3 dB)

Medium Throw (0 dB)

Frequency Response

The frequency repsonse graph represents measurements from a single VRX932LA speaker, applying the three

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

1 2 3 4 5 6 7 8 9 10 11 12

No comments

Jbl VRX932LA User Manual Page 5