EAW Three-way Loudspeakers - Manual (Page 3)

vocal region and give dialog exceptional warmth and clarity,
EAW always employs cone drivers for its mid frequency
subsystems.
Since three-way design divides the audio spectrum
between three subsystems, each only needs to cover a little
over three octaves – a range over which each driver can be
truly optimized. The high frequency compression driver
now operates only in the true high frequency range, mean-
ing better performance in the very high frequency range.
Similarly, optimized woofers can better handle the low fre-
quency sound effects that give films that “digital sound.”
T H R E E - W A Y I M P R O V E S O U T P U T
The maximum volume (peak output) that a loudspeaker sys-
tem can generate is related to two factors: sensitivity (output
generated by 1 Watt of power as measured at 1 meter) and
power handling (the amount of power a loudspeaker can
bear before failure).
Horn-loaded compression drivers enjoy excellent sensi-
tivity characteristics but handle relatively low amounts of
amplifier power, particularly when driven at very low fre-
quencies (i.e. 500 Hz). By comparison, a horn-loaded,
heavy-duty cone driver is somewhat less sensitive but han-
dles substantially more power. The calculated peak output of
the cone driven subsystem will be 6 - 10 dB higher than that
of an equivalent compression driven subsystem. Higher
peak output gives loudspeakers a greater dynamic range
throughout the audio spectrum, which particularly
improves reproduction of full range musical scores and
sound effects. It also permits a greater degree of passive fil-
tering to smooth the total system’s frequency response with-
out sacrificing peak output.
A C C U R A T E W I D E B A N D D I R E C T I V I T Y
The ability to put sound where it is needed and keep sound
away from where it is not wanted distinguishes well-
designed loudspeakers. When a loudspeaker with poor
directivity characteristics sends some frequencies at wide
angles and others at narrow angles, listeners at the edges of
its coverage area will hear some frequencies and not others.
Furthermore, uncontrolled soundwaves reflecting off walls
and ceilings can create unacceptable reverberations that
degrade the sound quality in the entire venue.
The directivity characteristics of a loudspeaker can vary
widely depending on the frequency and the size of the
sound producing device. The rule of thumb goes as follows:
as the length of a sound wave decreases (with rising frequen-
cy) to approach the size of the driver cone or horn mouth,
directivity narrows; as the sound wave becomes smaller than
the size of the driver or horn mouth, directivity becomes too
narrow for most applications including cinema. The lower
the frequency, the more difficult it is to confine to a narrow
angle; the higher the frequency, the more difficult it is to dis-
perse at a wide angle.
Traditional two-way cinema loudspeaker design uses an
exceptionally large high frequency horn to provide pattern
control at 500 Hz (which it does admirably). But making
very high frequency sound waves “fill the bell” of the horn
requires an exceptionally long horn throat. So long, in fact,
that cancellation effects within the horn throat cause signifi-
cant, audible distortion in the 700 Hz region. Smaller for-
mat high frequency horns one encounters for smaller cine-
mas produce much less distortion, but lack the necessary
pattern control at 500 Hz.
By asking each subsystem to cover a smaller range than
two-way designs, three-way loudspeakers can control both
mid and high frequencies without introducing distortion.
EAW’s larger three-way cinema designs – CB223 and
MC4972 – employ smaller format high frequency horns
with very short throats. Since they don’t need to control
sounds in the 500 Hz range, their size is quite manageable.
These horns disperse the highest frequencies across a wide
area without noticeable distortion. Our smallest three-way
cinema system, CB150, loads a compression driver on our
shallow, throatless Wave Guide Plate™ giving high frequen-
cies an exceptionally smooth character.
EAW’s proprietary manufacturing techniques allows us to
produce the most mathematically accurate mid frequency
horns in the industry. Automated saws and routers cut
grooves in the enclosure that accept a flexible hardwood
veneer shell which acts as a form for structural foam which
we inject into the enclosure. The foam/veneer horn provides
much greater rigidity than fiberglass horns, allowing it to
control mid frequency sound waves with greater ease.
20 100 1000 10000 20000
dB SPL
Frequency (Hz)
2-way w/ compression driven high frequency
distortion comfort
20 100 1000 10000 20000
Frequency (Hz)
3-way w/ compression driven midrange
distortion comfort
dB SPL
c o n t i n u e d