JBL GT 4.0C User Manual / Operation Manual ▷ View online
09
2. The best center image will be
achieved when the distance from
the left speaker and the right
speakers are as equal as possi-
ble from your listening position.
This is most easily achieved by
placing the speakers as far for-
ward as possible.
3. Treble is directional in nature.
This means that high frequencies
are reduced as you move off the
tweeter's axis. The angle mounts
will allow the GTC04 tweeters to
be pointed across the car to the
listener on the opposite side. This
will make each listener slightly
off-axis to the tweeter that is
closest to that listener, which
helps to compensate for the fact
that the listener is always closer
to one tweeter than to the other
(see Figure 6).
Component Placement
Because of the JBL Component
System’s small size and ex-
tremely versatile mounting
options, there are an almost infi-
nite number of placement options
to achieve excellent sound quality
in any vehicle. Please consider
the following statements to help
you get the most from your
system.
1. The most spacious stereo
image is achieved when the left
and right speaker systems are
placed as wide apart as possible.
The best system integration is
achieved when the tweeter is
mounted close to the midwoofer
speaker. This helps smooth the
transition from the midrange and
tweeter crossover point.
Choosing mounting locations
which satisfy all of the above cri-
teria will provide the most satis-
fying performance.
Figure 6
GT4.0c, 5.0c, 6.0c OM 7/16/98 9:54 AM Page 9
10
System Design
There are a variety of system
options available with the
Component System. The simplest
configuration is to use them full
range with their built-in passive
crossovers by connecting them to
the output of a head unit or an
amplifier (Figures 7 and 8).
If you want to build your system
using active (electronic)
crossovers, with separate ampli-
fiers to drive the tweeter and
midwoofers, you can bypass the
capacitor on the tweeter and the
coil on the midwoofer (Figure 9).
A more advanced system design
can be achieved by adding a GT,
GTx, GTi, or equivalent sub-
woofer to your component sys-
tem. In this case the component
system will be used as high and
midbass frequency drivers and
should have their extremely low
frequencies blocked by electrical
means. Active or passive cross-
overs can be used in order to
achieve the best system fidelity
and widest dynamic range. Cross-
over frequency recommendations
are given in the Specifications.
+
+
Left
Right
Left
Channel
Right
Channel
In-line
Capacitor
–
GTC04
Tweeters
–
–
GTC Component System
connected to speaker outputs of
a High-Powered Head Unit
GTC
Midwoofers
–
–
+
+
–
–
Left
Right
Left
Channel
Right
Channel
In-line
Capacitor
–
GTC04 Connected to GTC Midwoofer,
GTC Midwoofer Connected to Amplifier
GTC04
Tweeters
-
-
GTC
Midwoofers
Amplifier output
set at Full Range or
High Passed at f > 80Hz
–
–
Figure 7
Figure 8
GT4.0c, 5.0c, 6.0c OM 7/16/98 9:54 AM Page 10
11
Installation Warnings
and Tips
and Tips
• Be careful not to cut or drill
into fuel tanks, fuel lines, brake
or hydraulic lines, vacuum lines
or electrical wiring when work-
ing on your vehicle. Inspect
behind panels before you cut or
drill.
• Make sure that the midwoofer
will physically fit in the mount-
ing location. If door mounting,
check for adequate clearance
with the window in both rolled-up
and rolled-down positions as well
as for interference with window
crank and power window mecha-
nism. If mounting elsewhere,
check for clearance around rear
deck torsion bars, glove box or
other structural elements.
• Do not mount speakers where
water may splash on the cones.
• Make sure that it will be easy to
run connecting wires to the
speakers. Trace speaker wire
paths before you undertake
mounting.
• Always disconnect the ground
wire from the battery before
doing any work on the vehicle.
CAUTION: Fuel tanks are
located directly beneath the rear
deck in some cars. Check for
adequate speaker basket clear-
ance before considering this
location!
–
+
–
Left
Left
Channel
GTC04 and GTC Midwoofer Connected
Directly to Amplifier
Electronic
Crossover
Right
Amp for
Tweeters
f > 5khz
Amp for
Woofers
f < 5khz
Hi-Pass
Lo-Pass
Right
Channel
GTC04
Tweeters
GTC
Midwoofers
Figure 9
GT4.0c, 5.0c, 6.0c OM 7/16/98 9:54 AM Page 11
12
A Note on Power
Handling
Handling
As a result of their high effi-
ciency, all JBL loudspeakers will
produce reasonable volume levels
in the automotive environment
using very little amplifier power.
However, the use of a small
amplifier to attain very high vol-
ume levels could lead to over-
driving the amplifier. This will
generate high distortion levels
which can easily damage loud-
speakers, even if the rated power
of the amplifier is below the rated
maximum power handling of the
loudspeaker!
As a general rule, do not turn up
the volume control past the point
where you hear distortion in the
form of either signal distortion
from an overdriven amplifier or
mechanical noise from an over-
stressed speaker.
For the best performance and
system reliability, you should
select an amplifier with an output
rating greater than the maximum
power likely to be used to gener-
ate the desired volume levels.
If you want your system “Loud
+
Clear,” we suggest that you step
up to a JBL power amplifier
which has an RMS power rating
equal to, but not exceeding the
Maximum Recommended
Amplifier Power listed in the
specifications of your specific
JBL speaker. This margin of
reserve power will ensure that
the amplifier will not attempt to
deliver more power than its
design allows. Your dealer will be
happy to point out which high
power JBL amplifiers are opti-
mum for your application and
listening habits.
Following these guidelines will
provide virtually distortion-free
sound reproduction and long loud-
speaker life.
WARNING: Playing loud music
over 120dB can permanently
damage your hearing. The maxi-
mum volume levels achievable
with JBL components and high
power amplification may exceed
safe levels for extended listening.
When listening at high volume
levels, always use hearing protec-
tion or turn it down!
GT4.0c, 5.0c, 6.0c OM 7/16/98 9:54 AM Page 12
Click on the first or last page to see other GT 4.0C service manuals if exist.