JBL VRX932LA manual Amplitude Shading, Array Configuration Selector ACS, Frequency Response

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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)

Medium Throw (0 dB)

Long Throw (+3 dB)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Frequency Response

The frequency repsonse graph represents measurements from a single VRX932LA speaker, applying the three different ACS settings: +3dB, 0dB, -3dB.

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Contents VRX932LA Contents Introduction to the VRX932LA Dimensional DrawingsVRX932LA 12¨, two-way, line-array loudspeaker system SpecificationsFunctional Block Diagram Amplitude Shading Array Configuration Selector ACSAmplitude Shading Frequency ResponseBi-Amplified System System Processor Tunings Single VRX932LA Deploying the SystemLocking 2 VRX932LA Loudspeakers Together Dual VRX932LAVRX932LA-AF Array Frame Suspension Safety WarningsGround-Stacked, Upward Firing Arrays Installing the Array FrameAdding a Second Array Frame for Pullback JBL Warranty and Contacts