JBL Grand Touring Series GTO
subwoofers are available in two
different configurations: a single
4-ohm voice coil or dual 4-ohm
voice coils. You may use GTO
subwoofers in singles or multiples
to maximize the power available
from your amplifier(s). To achieve
the maximum amplifier output
possible, you should design a
speaker system that provides
the lowest impedance that your
amplifier will drive safely. When
designing a subwoofer system,
consider the following rules:
1. Do not mix different subwoofers
or enclosure types in the same
system. Subwoofers being used in
the same enclosure or powered
by the same amplifier should
be identical models. Mismatched
woofers and enclosures can
result in poor performance from
your subwoofer system.
2. You may connect the coils of a
dual-voice-coil woofer in series,
but we recommend that you avoid
connecting separate woofers in
series.
3. You must use both coils of a dual-
voice-coil woofer connected
either in series or in parallel.
4. Most amplifiers deliver exactly
the same amount of power
bridged into a 4-ohm load
as they do running a 2-ohm
stereo load.
To design a subwoofer system
that maximizes available amplifier
power, keep the following rules
in mind:
1. The total system impedance
of woofers in parallel can be
calculated using the formula:
Impedance =
1
1
+
1
+
1 ...
w
1
w
2
w
3
where w is the nominal
impedance of the woofer.
2. The total system impedance
of voice coils (or woofers) in
series can be calculated using
the formula:
Impedance = w
1
+ w
2
+ w
3
...
The diagrams at right show parallel
and series speaker connections.
Figure 1. Parallel connection
Figure 2. Series connection
3
CONNECTING YOUR SUBWOOFER TO YOUR AMPLIFIER
