JBL 500GTi - Manual (Page 9)

to tweeter transition. Set the high crossover
frequency at or above 5kHz if a 12dB per
octave crossover is used and at or above
3.5kHz if you are using an 18 or 24dB per
octave crossover. For safety, the maximum
recommended amplifier power routed
directly to the 400 and 500GTi Midrange is
150 watts for the 400GTi and 200 watts for
the 500GTi.
A Note on Power Handling
As a result of their high efficiency, all
JBL loudspeakers will produce reasonable
volume levels in the automotive environment
using very little amplifier power. However, the
use of a low-powered amplifier to attain very
high volume levels could lead to overdriving
the amplifier. This will generate high
distortion levels which can easily damage
loudspeakers,
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 overstressed 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 generate 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 it’s design allows. Your dealer will
be happy to point out which high power JBL
amplifiers are optimum for your application
and listening habits.
Following these guidelines will provide
virtually distortion free sound reproduction and
long loudspeaker life.
In Case of Difficulty
The most common difficulties are noise,
distortion, and intermittent connections.
System noise is usually not the fault of
the 400 and 500GTi. Hiss or “alternator
whine” is most often the result of faulty
grounding of the system electronics or
improper setting of amplifier level controls. An
exception to this is if the passive crossover
components are mounted near a source of
radiated noise, the network may pick-up this
noise with sufficient power to drive the 400
and 500GTi. For this reason, be careful not to
mount any passive crossover components
near wires carrying high currents such as
battery cables or wires leading to ammeters
or tachometers.
Distortion is usually the result of
overdriving one or more components in the
system. The problem is most likely insufficient
amplifier power, or improper setting of gain
controls. Refer to the instructions which came
with the electronics for assistance. The 400
and 500GTi will not play as loudly, or handle
the full rated power, when used without a
high-pass crossover. When using the 400 or
500GTi full-range, be careful to limit the
volume level to that which can be reproduced
without audible distortion from the speaker.
If you want to talk to us about any
problems, call JBL Customer Service at
1-800-336-4JBL (4525) between 9AM and
5PM eastern time.
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400/600 MANUAL.QXP 7/17/98 11:10 AM Page 9