JBL GTH400-20107 - Manual (Page 20)

19
position for driver-optimized sound
stage.
5. Proceed to push and pull the Rear-
Ambience knob to hear the effects
of “Driver” and “All” modes. You
should hear imaging coming from
the middle of the dashboard when
the knob is pushed in (“Driver”
mode). You should hear stereo with
ambience recovery when the knob
is pulled out (“All” mode). If you find
that the center imaging in the
“Driver” position is slightly offset to
the left or right side of the
dashboard, switch the car-size
switch located inside of the
GTH400 under the bottom cover as
shown below. This switch optimizes
the Imaging Enhancer for standard
or large cars.
6. Slowly turn the “Front-Ambience”
knob in the clockwise direction to
increase ambience. You should
begin to hear slight reverberation in
the music and a sense of a
widening front sound stage in both
the “Driver” and “All” modes.
7. Slowly turn the “Rear-Ambience”
knob in the clockwise direction to
increase rear ambience (only in
systems with rear speakers). You
should begin to hear an increase in
reverberation and get a feeling of
being in a very large auditorium.
Note: The GTH400 converts the
rear channels into true rear-fill
surround channels which cancel
all center information (vocals, lead
instruments, etc.) and lets only true
ambience information come out.
This same process is used in more
expensive “Surround Sound”
systems used in theaters.
8. Adjust the front and rear ambience
as desired. For optimum center
imaging, it is recommended that
ambience be used sparingly on the
front channels.
9. To bypass the effects of the
Imaging Enhancer in the GTH400,
simply pull on the “Front-
Ambience” knob until it clicks to the
“Bypass” position. The “Enhancer
On” LED on the remote control
panel will turn off and your sound
system should revert back to
normal stereo sound without
ambience enhancement. The
Imaging Enhancer is also bypassed
when the remote control is
unplugged from the amplifier.
6. Important Characteristics
Overload Protection – The GTH400
incorporates elaborate protection cir-
cuitry to prevent damage to the
amplifier circuitry and ensure reliable
operation. This circuitry will turn the
amplifier off in the event of overheating,
a short circuit on the speaker output
wiring, or improper power supply
connections. If the amplifier cycles on
IMAGE
ENHANCER
MODULE
FRONT
PLATE
IMAGING ENHANCER
REMOTE PLUG
Standard Large
Imaging Enhancer
Car Size Switch
GTH400-20107 06/03/98 15:50 Side 19