A U T O M O T I V E S U B W O O F E R S
SERIES
Grand Touring® Series
GT1041, GT1041D, GT1081, GT1241, GT1241D, GT1281
Owner’s Manual
Figure 2. Series connection
To design a subwoofer system that
m axim izes available am plifier power,
keep the following rules in m ind:
1. The total system im pedance of
woofers in parallel = 1/(1/w1 + 1/w2
1/w3...) where w is the nom inal im ped-
ance of the woofer.
2. The total system im pedance of voice
Connecting Your Subw oofer to Your
Am plifier
2. You m ay connect the coils of a dual-
voice-coil woofer in series, but NEVER
connect separate woofers in series.
Because the am plifier-dam ping factor
(the am plifier’s ability to control the
m otion of the woofer) is expressed as
a ratio of term inal im pedance (the sum
of speaker im pedance, wire resistance
and the D.C. resistance of any
crossover coil connected to the
woofer) to am plifier-output im ped-
ance, connecting woofers in series
reduces the dam ping factor of the
am plifier to a value less than 1. This
will result in poor transient response.
3. You m ust use both coils of a dual-
voice-coil woofer either in series or in
parallel.
J BL GT Series subwoofers are available
in three different configurations: single
4-ohm voice coil, single 8-ohm voice coil
and dual 4-ohm voice coils. Depending
on the am plifier you are using, you m ay
use either single- or dual-voice-coil
subwoofers in singles or m ultiples to
m axim ize the power available from your
am plifier. To achieve the m axim um
am plifier output possible, you should
design a speaker system that provides
the lowest im pedance that your am plifier
is rated to drive safely. When designing
a subwoofer system , abide by the
following rules:
+
coils (or woofers) in series = w1
2 + w3...
+
w
The diagram s below and at right show
parallel and series speaker connections.
Figure 1. Parallel connection
1. Don’t m ix different subwoofer or enclo-
sure types in the sam e system (use all
single-coil 4-ohm woofers, all single-
coil 8-ohm woofers, or all dual-coil
woofers).
4. Most am plifiers deliver exactly the
sam e am ount of power bridged into
a 4-ohm load as they do running a
2-ohm stereo load.
0 3
Specifications
GT1041
GT1041D
GT1081
GT1241
GT1241D
GT1281
Configuration
10" subwoofer
10" subwoofer
10" subwoofer
12" subwoofer
12" subwoofer
12" subwoofer
Recom m ended Am plifier
Pow er Range
18W – 275W
4 ohms
18W – 275W
dual 4 ohms
90dB
18W – 275W
8 ohms
18W – 300W
4 ohms
18W – 300W
dual 4 ohms
93dB
18W – 300W
8 ohms
Im pedance
Sensitivity
90dB
90dB
93dB
93dB
Frequency Response
Mounting Depth
20Hz – 500Hz
20Hz – 500Hz
20Hz – 500Hz
18Hz – 500Hz
6" (153m m )
18Hz – 500Hz
6" (153m m )
18Hz – 500Hz
6" (153m m )
5-3/8" (137m m )
9-1/4" (235m m )
5-3/8" (137m m )
9-1/4" (235m m )
5-3/8" (137m m )
9-1/4" (235m m )
Cut-Out Diam eter
11-1/8" (283m m )
11-1/8" (283m m )
11-1/8" (283m m )
Declaration of Conformity
We, JBL Europe A/S
Kongevejen 194B
DK-3460 Birkerod
DENMARK
declare in own responsibility, that the products
described in this owner’s manual are in compliance
with technical standards:
EN 50081-1:1992
EN 50082-1:1992
Steen Michaelsen
JBL Europe A/S
JBL Consumer Products, 250 Crossways Park Drive, Woodbury, NY 11797
800-336-4JBL (4525) www.jbl.com Part No. GTSUBOM Made in USA
Birkerod. DENMARK. 5/99
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