JBL MkII automotive User Manual
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INSTALLATION WARNINGS AND TIPS
WARNING
Playing loud music in an automobile can
hinder your ability to hear traffic, as well
as permanently damage your hearing.
We recommend listening at low levels
while driving. JBL accepts no liability for
hearing loss, bodily injury or property
damage resulting from use or misuse of
this product.
YOUR CAR AND BASS
REPRODUCTION
Depending on the size of the vehicle’s
interior listening space, reproduced
frequencies below 80Hz may be boosted
by nearly 12dB per octave as frequency
decreases. This effect, commonly known
as transfer function, or cabin gain, plays
an important role in defining the in-car
frequency response of your subwoofer.
It is displayed graphically, along with
freespace response, on the enclosed
data sheet for your GTi subwoofer.
POWER-HANDLING
LIMITATIONS
The power-handling capacity of any
subwoofer is related to the excursion
limit of its suspension and its ability to
dissipate heat. A speaker reaches its
excursion-limited power-handling
capacity when its suspension is
stretched to its limit. The excursion
curve shown on the Enclosure Design
Sheet (included with your woofer)
displays cone excursion at the input
power level required to drive the woofer
to maximum linear excursion (X
max
).
The input power shown may be used
as instantaneous input only.
Thermal power handling is determined
by the amount of heat that may be
dissipated by the driver’s voice coil.
The power-handling rating assigned
to your GTi Series subwoofer is its
thermal-power-handling rating. This
rating assumes a clean (unclipped)
signal. A clipped waveform has much
higher average power, due to the longer
duty cycle at the top and bottom of the
waveform; it will heat the woofer’s voice
coil faster than a clean signal and may
damage the voice coil. A square wave
has a 100% duty cycle and is extremely
dangerous for any speaker. Audible
distortion in the output of your woofer
is an indication that your amplifier may
be clipping, which could damage your
speakers over time.