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If all the speakers connected in series are the same impedance,
then the total impedance
is the impedance
of one speaker
multiplied by the number of speakers. The power delivered
to any one speaker is the total power delivered to the group,
divided
by the number
of speakers.
For example,
if four
eight-ohm
speakers
are cónnected
in series, the total load
impedance is 32 ohms. An amplifier rated at 75 watts into 4
ohms would deliver 1/4 that power, or about 19 watts, into
32 ohms. Thus, one of the four speakers would dissipate 1/4
of that
power,
or just under
5 watts.
(If the speaker
impedances
are
dissimilar,
the highest
impedance
driver
receives the most power.)
SINGLE
TWO SPEAKERS
THREE SPEAKERS
SPEAKER
IN SERIES
IN SERIES
4 ohms
8 ohms
12 ohms
8 ohms
16 ohms
24 ohms
16 ohms
32 ohms
48 ohms
+
1/2 X watts
1/3 X watts
X watts
Fig. 15 IMPEDANCE OF SERIES-WIRED SPEAKERS, AND POWER
FOUR SPEAKERS
IN SERIES
16 ohms
32 ohms
64 ohms
1/4 X watts
"DRAWN"
FROM AN AMPLIFIER
RELATIVE TO ONE SPEAKER.
Speakers connected in parallel present a load to the amplifier
that is lower impedance
than the impedance of any one of
the drivers. This represents a greater load to the amplifier,
and also draws more power. Parallel wiring can be thought of
as a pair of parallel
wires where
individual
drivers are all
connected
across
the
two
wires.
М all the speakers
are
identical, then the total impedance of the array is simply the
impedance of any one of the drivers divided by the number
of drivers.
For example, three 16 ohm drivers connected in
parallel represents a total load impedance
of 16/3, or 5.33
ohms.
Connected
to an amplifier rated at 75 watts into 4
ohms, this load would draw about 56 watts. Thus, one of
the four speakers would
dissipate 1/4 of 56, or about 14
watts. In this case, the parallel wiring results in greater overall
power delivered to the speakers.
SINGLE
TWO SPEAKERS
THREE SPEAK
SPEAKER
IN PARALLEL
IN PARALLE
4 ohms
2 ohms
1.33 ohms
8 ohms
4 ohms
2.66 ohms
16 ohms
8 ohms
5.33 ohms
4
X watts
2 X watts
3 X watts
Fig. 16
IMPEDANCE OF PARALLEL-WIRED SPEAKERS, AND POWER
ERS
L
FOUR SPEAKERS
IN PARALLEL
4 X watts
NOTE:
"DRAWN"
FROM AN AMPLIFIER
RELATIVE
TO ONE SPEAKER.
Impedances below. 4 ohms should not be connected to a single amplifier channel
output; impedances below 8 ohms should not be connected to a stereo amplifier
operated in bridged mode (for these particular Yamaha amplifiers).
20
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