JBL Grand Touring GT1000 User manual

GRAND TOURING®SERIES
GENUINE JBL
Automotive Subwoofers
GT800, GT800d, GT1000, GT1000d, GT1200, GT1200d, GT1500, GT1500d Owner’s Manual
GTSubwoofers Owner's Manual 7/14/98 2:19 PM Page 1

01
installation methods for your par-
ticular vehicle. If you do not feel
you have experience, do not
attempt the installation yourself,
but instead ask your authorized
JBL dealer about professional
installation options.
Remember to keep your sales
receipt with this manual in a safe
place so both are available for
future reference.
Thank you for choosing a
JBL GT Series subwoofer. GT
Series subwoofers are designed
to suit a broad range of mobile
audio applications and can be
used in a wide variety of enclo-
sure types to produce extended,
powerful bass in a limited
amount of vehicle space. To
ensure maximum subwoofer
performance, we strongly rec-
ommend that installation be left
to a qualified professional.
Although these instructions
explain how to install a GT
Series subwoofer in a general
sense, they do not show box con-
struction details and exact
Enclosure Calculations
and Building Boxes
Use the recommended box
designs on the enclosed data
sheet or look for them on our
Web site at www.jbl.com. Choose
cabinet dimensions to fit your
vehicle, but do not change the
enclosure’s volume. Doing so will
change the tuning frequency of
the enclosure and may adversely
affect final performance. If you
cannot perform the necessary
calculations yourself, please con-
tact your authorized JBL dealer
for help and information about
JBL Speakershop™, a dedicated
enclosure-design software pro-
gram for experienced car-audio
enthusiasts.
Your Car and Bass
Reproduction
Depending on the size of the vehi-
cle’s interior listening space,
reproduced bass frequencies
below 80Hz are actually boosted
by nearly 12dB per octave as fre-
quency decreases. NOTE: This
effect, known as the vehicle’s
transfer function, plays an impor-
tant part in shaping the overall
in-car response and is displayed
graphically along with freespace
response on the enclosed data
sheet for your GT Subwoofer.
GTSubwoofers Owner's Manual 7/14/98 2:19 PM Page 2

Specifications
GT Speakers
Specifications: GT800 GT800d GT1000 GT1000d
Configuration 8" woofer 8" woofer, 10" woofer 10" woofer,
dual voice coil dual voice coil
Recommended power amplifier range 18W – 200W 18W – 200W 18W – 260W 18W – 260W
Sensitivity (@ 2.83 volt/1 meter) 93dB 93dB 94dB 94dB
Frequency response 35Hz – 5kHz 35Hz – 5kHz 30Hz – 3.5kHz 30Hz – 3.5kHz
Mounting Depth
Top mount 3-13/16" (97mm) 3-13/16" (97mm) 5-1/8" (131mm) 5-1/8" (131mm)
Bottom mount 4-5/16" (110mm) 4-5/16" (110mm) 5-5/8" (143mm) 5-5/8" (143mm)
Dimensions
Cut-out diameter 7-1/8" (181mm) 7-1/8" (181mm) 9-1/4" (235mm) 9-1/4" (235mm)
Specifications: GT1200 GT1200d GT1500 GT1500d
Configuration 12" woofer 12" woofer, 15" woofer 15" woofer,
dual voice coil dual voice coil
Recommended power amplifier range 18W – 280W 18W – 280W 18W – 300W 18W – 300W
Sensitivity (@ 2.83 volt/1 meter) 95dB 95dB 97dB 97dB
Frequency response 25Hz – 3kHz 25Hz – 3kHz 20Hz – 2kHz 20Hz – 2kHz
Mounting Depth
Top mount 3-3/8" (86mm) 5-3/4" (147mm) 5-3/4" (147mm) 6-11/16" (170mm) 6-11/16" (170mm)
Bottom mount 6-1/4" (159mm) 6-1/4" (159mm) 7-3/16" (183mm) 7-3/16" (183mm)
Dimensions
Cut-out diameter 11-1/8" (283mm) 11-1/8" (283mm) 13-15/16" (355mm) 13-15/16" (355mm)
01
GTSubwoofers Owner's Manual 7/14/98 2:19 PM Page 3

(i.e., entire box is stuffed with
loosely-packed polyester fiberfill).
4. Use PVC or ABS pipe for ports.
Keep in mind that the openings at
either end of the port must be at
least one port diameter away
from any obstructions, including
filling material inside or outside
the box. Rectangular vents can
be used as long as the cross-
section area matches the
recommended port-area values
in the enclosed data sheet.
2. Seal all joints with glue and
screws; do not use nails. We
recommend “deck” or “zip” screws
since they have coarse threads
for better grip and don’t require
pre-drilling holes. Once the box
has been tested, seal all interior
joints with silicone caulk.
3. Depending on the application,
fill the enclosure according to the
design you have chosen from the
enclosed data sheet in one of three
ways: zero-percent fill (i.e., no
fill), or 50-percent fill (i.e., 1"-
thick polyfill sheets on all inside
walls except where subwoofer is
mounted), or 100-percent fill
Sealed enclosures exert the most
control over the motion of a sub-
woofer because the air acts like
a spring against the motion of
the woofer cone. Larger boxes
allow for more excursion (cone
movement), thus more low-
frequency output for the amount
of power used. When placed in a
sealed box larger than the com-
pliance (Vas) of the subwoofer, it
will perform as if it were in an
infinite baffle installation.
Vented and bandpass enclosures
have the lowest amount of excur-
sion for the amount of sound out-
put. This is a result of port tuning
reinforcing the sound output.
Vented boxes will not provide
adequate woofer control when dri-
ven below the port tuning range,
so proper design is important. A
fourth-order bandpass box will
have the lowest overall cone
excursion at the expense of limited
bandwidth.
In addition, there are a number of
points you’ll want to keep in mind
as you construct an enclosure:
1. Use 3/4" (19mm) MDF (medium-
density fiberboard) or marine
birch plywood to build an enclosure.
Enclosures for 12" and larger
subwoofers, or small subwoofers
driven by high-power amplifiers,
should be constructed using 1"
(25mm) material.
01
GTSubwoofers Owner's Manual 7/14/98 2:19 PM Page 4

Power-Handling
Limitations
The power-handling capability of
any woofer is related to both its
ability to dissipate heat and the
maximum excursion limits of its
cone. Once the speaker’s voice
coil moves outside the magnetic
gap, power can no longer be con-
verted into motion, and all the
amplifier’s power is converted
into heat in the voice coil. This
voice-coil heating is the largest
detriment to speaker longevity,
so overexcursion (driving the
speaker past Xmax) should be
avoided. Since speaker-cone
excursion is different for each
type of enclosure, power handling
is different for each enclosure.
• Voice-coil overheating and burn-
ing due to over-excursion is often
caused by overdriving an ampli-
fier into “clipping.” A severely
clipped signal, or squarewave,
contains nearly twice the power
of a clean sine wave at the same
level. Bass that sounds broken up
and distorted at higher volumes
usually indicates that the ampli-
fier is being asked to deliver
power beyond its ability.
• Infinite baffle or “free air”
mounting applications allow for
greater cone excursion than sub-
woofers mounted in an enclosure.
In order to compensate, recognize
that the power-rating value of the
subwoofer will likely be half its
rated power in this application.
• Study the excursion curves on
the enclosed GT Series data
sheet and note the differences
for different enclosure applica-
tions. The type and size of box
used will produce different excur-
sion demands on the enclosed
subwoofer and, consequently,
different levels of power han-
dling. As long as recommended
parameters are used, the sub-
woofer will perform properly in
its enclosed environment.
However, any design deviation
may result in less than optimum
performance, and may also
subject the subwoofer to over-
excursion that can eventually
damage the speaker. For
additional help with this issue,
please contact your authorized
JBL dealer.
GTSubwoofers Owner's Manual 7/14/98 2:19 PM Page 5

JBL Consumer Products
250 Crossways Park Drive
Woodbury, NY 11797
8500 Balboa Blvd.
Northridge, CA 91329
800-336-4JBL (4525)
www.jbl.com
Part No. GTAUTOSUBOM
Made in USA
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Declaration of Conformity
We, JBL Europe A/S
Kongevejen 194B
DK-3460 Birkerød
DENMARK
declare in own responsibility, that the products described
in this owner’s manual are in compliance with technical
standards:
EN 50 081-1/1992
EN 50 082-1/3.1995
Steen Michaelsen
JBL Europe A/S
Birkerød. DENMARK. 2/98
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