K2S4800 (serv.man2) - JBL Audio User Guide / Operation Manual. Page 4

The new S4800 employs a 3-way,
three-driver design, incorporating
an ultrahigh-frequency (UHF)
compression driver and horn to
reproduce high frequencies up to
40kHz. With the UHF handling the
ultrahigh 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 woofer
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.

In order to re-create the extremely
high dynamic range provided by
today’s audio sources, a new low-
frequency transducer was used,
incorporating a ferrite magnet, 
3-inch edge-wound voice coil, and
an Aquaplas-coated 15-inch cone
made of Kevlar

®

composite, a

mixture of Kevlar fiber and pulp
material that provides increased
rigidity. An EPDM rubber surround
was chosen for both its flexibility
and long life. The Symmetrical Field
Geometry

™

(SFG

™

) magnetic

structure minimizes second
harmonic distortion by providing a
uniform flux field that prevents
uneven cone movement. The rigid
cast-aluminum frame is also
designed to minimize distortion, as
aluminum has no effect on the
magnetic field. Extensive computer-
aided engineering and design effort
made to develop the optimized port
tuning employed in the S4800 has
resulted in a significant advance in
the concept of state-of-the-art bass
reproduction. This proprietary
alignment method offers the best
damping characteristics and
provides extremely fast alignment,
eliminating the typical “bass-
reflex” sound of a ported system.

All three transducers are built using
the most advanced materials and
precision manufacturing
techniques refined from renowned
JBL professional sound systems.

High power-handling capability
results in no limitations on the types
of source material. The S4800 has
very high input sensitivity; even a
relatively small high-end amplifier
can provide full dynamic range
without compression.

Despite its power and
sophistication, the S4800 embodies
both tradition and technology. It
reflects the design, engineering
and manufacturing expertise
derived and refined through nearly
six decades of experience that are
the exclusive province of one
loudspeaker builder – JBL.

4

Figure 1. 
Cutaway view of S4800 speaker system.