GTH 400 (serv.man2) - JBL Car Audio User Guide / Operation Manual. Page 5

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JBL’s breakthrough “Virtual Center”
circuitry is the result of the
understanding of how the human ear
responds to timing, frequency, and
amplitude cues to determine the
apparent direction of a sound source.
Virtual Center circuitry manipulates the
analog signal in real time to provide
each of the driver’s ears with the signal
they would receive if the driver was
seated in the center of the vehicle. This
provides a stable, centered image to
the driver much like that obtained with
a dedicated center-channel
loudspeaker.

To restore the spaciousness that is
generally lost in the small confines of a
car interior, the rear channels utilize
differential-mode ambience recovery to
restore the ambience information pres-
ent in all conventional stereo
recordings. Unlike DSP, the JBL
circuitry does not add synthetic reverb,
but recovers real information that is
masked in conventional systems. As a
result, the overall effect from the Virtual
Center circuitry of the GTH400 is
incredibly realistic, yet simple to adjust
and use. Best of all, the “Virtual Center”
and ambiance recovery circuits do not
require specially encoded recordings
and work with virtually all conventional
stereo tapes, discs, and broadcasts.

Although the GTH400 is designed to
make installation as easy as possible, it
is an extremely sophisticated product
that requires proper installation and
setup to realize its full performance
potential. If you feel you do not have
the necessary knowledge and skills, we
strongly recommend that the
installation be done by your
authorized JBL dealer.

If you choose to install the GTH400
yourself, read 

all of the information in

this manual before you start the
installation. Pay particular attention to
the safety precautions and notes.

GTH400-20107  06/03/98 15:49  Side 4