Xi-2181/2181F
X-Array™ Install
Bass System
•Unprecedented acoustic output in a small, lightweight package
•Ring-Mode Decoupling (RMD)™ provides accurate transient detail
•EVX-180B woofers
•Unique rear-hinge rigging
•Flying and non flying configuration
Description
The X-Array Install™ product line repre- sents important advancements in concert- sound-reinforcement technology. The design goals called for the highest acoustic output capability with the highest fidelity in light- weight, compact enclosures that were easy to array. The development began with a clean sheet of paper and took an integrated ap- proach. The individual loudspeaker drivers, horns, enclosures, rigging hardware and sys- tem configurations were designed from the ground up specifically for this high-perfor- mance application.
The Xi-2181 is a manifolded, vented-box bass system utilizing two 457-mm (18-in.) woofers. The two woofers face each other in a manifold chamber at the center of the enclosure. This manifolding technique (U.S. Patent Number 4,733,749) increases the acoustic loading, resulting in increased low- frequency efficiency (at slightly above box tuning) and reduced distortion compared to conventional direct-radiating designs. The woofers were designed as part of the Xi-2181 development and represent a step forward in state-of-the-art loudspeaker design in terms of high acoustic output with low distortion and low power compression. Electro-Voice engineers developed a new technology dubbed Ring-Mode Decoupling
(RMD™ ) to substantially improve clarity and intelligibility by reducing both linear and nonlinear resonance modes that color the sound.
The low-frequency driver in the Xi-2181 is the EVX-180B. An improved version of the industry-standard EVX-180A high-excur- sion 467-mm (18-in.) woofer that has dis- tinguished itself as an industry standard for high-power, low-frequency reproduction. During the X-Array™development, the ther- mal conduction of the motor was improved and the suspension was redesigned, giving the EVX-180B even lower power compres- sion and a longer mechanical lifetime. In the Xi-2181, the woofers are manifolded in a vented enclosure optimized for maximized output from 37-160 Hz with minimized dis- tortion.
Ring-Mode Decoupling, (RMD™ ), is a tech- nique utilized and named by Electro-Voice to describe a process used to improve sound quality in loudspeaker systems. RMD™ of- fers a solution to a very fundamental prob- lem. It has long been recognized that two different loudspeaker systems can sound dif- ferent even though they both may be equal- ized to have the same frequency response. This difference is due to a variety of reso- nances, or ring modes that color the sound. Although this ringing may be very low in level compared to the program material, it is
still audible. The source of these resonances may be mechanical or acoustical in nature, or a combination of both. In addition, they may be linear or nonlinear, resulting in their character changing with level. Furthermore, these ring-modes may be aggravated when multiple loudspeaker enclosures are as- sembled into arrays. The result is a colora- tion that decreases intelligibility and clarity, with the nature of that coloration varying with level. Often, the listener perceives that coloration as imbalance in the frequency re- sponse, and will attempt to electronically adjust the system to restore the spectral bal- ance. However this electronic equalization has the negative effect of changing the pro- gram material itself.
Ring-Mode Decoupling (RMD™ ) addresses mechanical resonances with mechanical solutions, and acoustical resonances with acoustical solutions. In the Xi-2181 devel- opment, RMD™ was applied at every level – to the individual low-frequency drivers, the low-frequency enclosure chambers and the interaction between multiple enclosures. The design process included, for example, the driver cone, suspension geometry and mate- rials, enclosure geometry and materials, ab- sorptive materials, etc. The result is a dra- matic improvement in clarity and with a much more neutral sound (a lack of colora- tion) with the loudspeaker system maintain-
