7
Parallel or series are the two basic ways which
multiple speakers can be connected to a single
power amplifier. When speakers are connected in
parallel, their combined impedance decreases. For
speakers wired in series the opposite is true, their
combined impedance increases. Also, when
speakers are wired in series, higher impedance
speakers in the series draw more power from the
amplifier than do speakers in the series with lower
impedances. When speakers are wired in parallel,
the opposite is true.
At Fender
®
, we recommend connecting multiple
speakers in parallel for several reasons. First, if one
speaker fails, the others will continue to operate.
Second, because in a series connection one
speaker affects the output of the other speakers,
unpredictable frequency response is a concern.
Third, most speaker cabinets are already wired for
parallel connections making parallel connections the
most common wiring method.
When using your SRM 6302 / 8302, be sure that the
minimum load connected to each channel is 4
ohms. Below are two charts demonstrating how to
calculate both parallel and series impedance.
Additionally, power and audio signal cables are the
most common sources of sound system failure.
Well made and carefully maintained cables are
essential to the reliability of the entire sound system.
If long speaker cables are required, it is important to
ensure the cable is sufficient to transfer all of the
available amplifier power to the speakers rather than
absorbing the power itself. As a rule of thumb,
larger wires are better as they conduct more power
to the speakers (larger wire has smaller gauge
numbers).
Below are two charts listing speaker wire gauges
and recommendations for best results.
SPEAKER WIRING AND CONNECTIONS
*Example - If the speaker wire length
required is between 25-50 feet (7.60-
15.25 meters) and the speaker
impedance is 8
Ω
, the minimum
recommended speaker wire gauge is 16.
100'-UP
(30.5 m-UP)
50'-100'
(15.25-30.5 m)
*25'-50'
(7.60-15.25 m)
10'-25'
(3.05-7.60 m)
0'-10'
(0.00-3.05 m)
SPEAKER WIRE GAUGE
SPEAKER IMPEDANCE [z]
SPEAKER WIRE LENGTH
AWG
Resistance in
Ω
per foot
(30.5 cm) @ 77º F (25º C)
18
16
14
12
10
.00651
.00409
.00258
.00162
.00102
8
.00064
0.83
1.32
2.10
3.32
5.27
8.38
10
12
14
12
14
16
14 *16
18
16
18
18
18
18
18
4
Ω
*8
Ω
16
Ω
Cross-
Section
[mm ]
2
Cabinet A
Impedance
Cabinet B
Impedance
16
Ω
*
8
Ω
8
Ω
* 16
Ω
PARALLEL IMPEDANCE
*Example- Cabinet A is 8 ohms. Cabinet B is
16 ohms . The total impedance when connected
in parallel is:
+
-
+
-
+ -
A
B
*Example- Cabinet A is 4 ohms. Cabinet B is
16 ohms. The total impedance when
connected in series is 4 + 16 = 20 ohms.
2
n
1
Z
Z
Z
...
+
Z s =
2
n
1
18
20*
24
32
10
12
16
24
6
8
12
20
4
6
10
18
Cabinet A
Impedance
Cabinet B
Impedance
16
Ω
*
8
Ω
4
Ω
2
Ω
2
Ω
4
Ω
*
8
Ω
16
Ω
+
-
+
-
+ -
B
A
SERIES IMPEDANCE
5.3*
8
4
5.3
...
1
1
Z
1
Z
1
Z
+
Z p =
1
8
1
16
+
1
= 5.3 ohms.
Z
p
=
