Thank you for choosing a JBL GTi Series
subwoofer. GTi Series subwoofers are
designed to provide maximum sound
output in a variety of enclosure types
while maintaining the superb sound quality
associated with JBL. To ensure the best
subwoofer performance, we strongly
recommend that installation be entrusted
to a qualified professional. Although
these instructions explain how to install a
GTi Series subwoofer in a general sense,
they don’t show the specific installation
procedures that may be required for your
particular vehicle. If you feel you don’t have
the necessary tools or experience, don’t
attempt the installation yourself; rather,
ask your authorized JBL dealer about
professional-installation options.
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.
02
The Official Brand of Live Music
