Xcb
X-Array™ Bass System
• Single-woofer design equivalent
to half of an Xb
• Ring Mode Decoupling (RMD)™
provides accurate transient detail
• EVX-180B woofer
• Unique rear-hinge rigging
• Enclosure shell and rigging
identical to all of the half-size
X-Array™ systems
Description
The X-Array™ product line represents im-
portant advancements in concert-sound-rein-
forcement technology. The design goals
called for the highest acoustic output capa-
bility with the highest fidelity in lightweight,
compact enclosures that were easy to array.
The development began with a clean sheet
of paper and took an integrated approach.
The individual loudspeaker drivers, horns,
enclosures, rigging hardware and system
configurations were designed from the
ground up specifically for this high-perfor-
mance application.
The Xcb is a manifolded, vented-box bass
system utilizing one 457-mm (18-in.) woofer
in the half-size X-Array™ enclosure shell.
The one woofer faces into a slotted cham-
ber at the bottom of the enclosure. This tech-
nique increases the acoustic loading, result-
ing in increased low-frequency efficiency (at
slightly above box tuning) and reduced dis-
tortion compared to conventional direct-ra-
diating designs. The woofers were designed
as part of the Xcb development and repre-
sent a step forward in state-of-the-art loud-
speaker design in terms of high acoustic out-
put with low distortion and low power com-
pression. Electro-Voice engineers developed
a new technology dubbed Ring Mode
Decoupling (RMD™) to substantially im-
prove clarity and intelligibility by reducing
both linear and nonlinear resonance modes
that color the sound.
The low-frequency driver in the Xcb is the
EVX-180B. An improved version of the in-
dustry-standard EVX-180A high-excursion
467-mm (18-in.) woofer that has distin-
guished 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
Xcb, the woofer is slot-loaded in a vented
enclosure optimized for maximized output
from 37-160 Hz with minimized distortion.
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.
Ring Mode Decoupling (RMD™) offers a
solution to a very fundamental problem. It
has long been recognized that two different
loudspeaker systems can sound different
even though they both may be equalized to
have the same frequency response. This dif-
ference is due to a variety of resonances, or
ring modes that color the sound. Although
this ringing may be very low in level com-
pared to the program material, it is still au-
dible. 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 char-
acter changing with level. Furthermore, these
Ring Modes may be aggravated when mul-
tiple loudspeaker enclosures are assembled
into arrays. The result is a coloration that de-
creases intelligibility and clarity, with the
nature of that coloration varying with level.
Often, the listener perceives that coloration
as imbalance in the frequency response, and
will attempt to electronically adjust the sys-
tem to restore the spectral balance. However
this electronic equalization has the negative
effect of changing the program material
itself.
Ring Mode Decoupling (RMD™) ad-
dresses mechanical resonances with me-
chanical solutions, and acoustical reso-
nances with acoustical solutions. In the
Xcb development, RMD™ was applied at
every level – to the individual low-fre-
quency drivers, the low-frequency enclo-
sure chambers and the interaction between
multiple enclosures. The design process
included, for example, the driver cone, sus-
pension geometry and materials, enclosure
geometry and materials, absorptive mate-
rials, etc. The result is a dramatic improve-
ment in clarity and with a much more neu-
tral sound (a lack of coloration) with the
loudspeaker system maintaining its sonic
integrity from the very-lowest sound pres-
sure levels to the very-highest sound pres-
