After
Project Everest
was intro-
duced, sound recording and play-
back technology underwent a
revolution of its own. With the
advent of CD, extremely demanding
recorded signals had become the
rule rather than the exception –
the average source material used
by the typical audio enthusiast
had become superior to the best
demonstration material of even just
a few years ago. In overall dynam-
ics and transient response, trans-
ducers were once again a potential
weak link in the high-end audio
reproduction chain.
It was in this environment that JBL
set out to create its fourth and fifth
Project
loudspeakers,
K2 S9500
and
K2 S5500
. As with
Hartsfield
, the
simplicity of a two-way system was
considered the most promising
design track. Advances in trans-
ducer design and low-frequency
alignment would make the con-
struction of a two-way system
of unprecedented physical and
acoustical scale possible. Engineers
took the core components – the
low- and high-frequency drivers –
and optimized them by redesign-
ing their magnetic structures,
diaphragms and framework for
greater linearity, dynamic capability
and transient response.
In the years following the introduc-
tion of the
K2 S9500
and
K2 S5500
,
sound reproduction technology has
undergone another series of revolu-
tionary changes, with the introduc-
tion of DVD-Video, Dolby* Digital,
DTS,
®
DVD-Audio, and Super Audio
CD (SACD). Frequency responses to
50kHz and 3-digit dynamic range
and signal-to-noise ratios have now
become commonplace. In order to
faithfully reproduce such robust
sonic properties, the loudspeaker
needed to undergo drastic improve-
ments to its transducer, network
and enclosure technologies.
See Figure 1.
Unlike the earlier
Projects K2 S9500
and
K2 S5500,
the new
K2 S5800
employs a 3-way, four-driver
design, incorporating an ultrahigh-
frequency (UHF) compression driver
and horn to reproduce high fre-
quencies up to 50kHz. With the UHF
handling the high frequencies, the
high-frequency (HF) transducer
could then be upgraded to a new
design using a 3-inch diaphragm
for better reproduction of lower
frequencies and better blend with
the dual woofers than the older
generations’ 2-inch diaphragm.
Both compression drivers are
mounted in a unique combination
Bi-Radial
®
horn structure,
precision-molded from JBL’s
proprietary SonoGlass
™
material, an
extremely dense and mechanically
inert substance that is easily
molded into the unusual shapes
required for superior acoustic
performance.
5
SonoGlass
Bi-Radial Horn
90
°
Horizontal
50
°
Vertical
Curved
Dress
Panel
Spiked Feet
Foot Base
1" MDF
Construction
1200FE
12" LF
Driver
1200FE
12" LF
Driver
Port
Tube
435AL
3" HF
Compression
Driver
045Ti
1" UHF
Compression
Driver
Figure 1. Cutaway view of
Project K2 S5800
speaker system.
