AVSL Sound & Light Product Guide 2024 - Catalog - Page 163
TECHNICAL DATA | TYPES OF SYSTEM | STANDARD LOW IMPEDANCE SPEAKERS
163
Standard Low Impedance Speakers
Impedance is measured in Ohms (Ω). Higher impedance
opposes the output of the ampli昀椀er more, causing it to deliver
less power, whereas lower impedance allows the ampli昀椀er to
deliver more power.
Since the coil is wound from very thin wire, there is a certain
amount of resistance to the electricity passed through it.
This, coupled with some other electrical characteristics,
is known as impedance.
The ampli昀椀er needs this impedance to stop itself from
over-working and burning itself out, and is an important
consideration when matching ampli昀椀ers and speakers
together in a system.
Impedance visual
representation:
1
2
3
The speaker impedes any
electrical current 昀氀owing
through it, in the same way
that the neck of an hourglass
impedes the sand 昀氀ow.
The narrow neck
controls the
昀氀ow of sand just
as a speaker’s
impedance controls
the 昀氀ow of current
2 narrow necks
makes it half as
dif昀椀cult for the sand
to pass through,
just as 2 parallel
speakers have half
the impedance as
1, allowing twice as
much power to
昀氀ow through
If the neck is too wide
it offers too little
control, just as
when the speaker
impedance is too low
and allows too much
power to 昀氀ow from
the amp, resulting in
eventual failure
For any given ampli昀椀er, the impedance of the speakers
attached to it must not be below the rated output impedance
of the ampli昀椀er and must be rated to handle the power that
the ampli昀椀er will deliver at that impedance.
Basic low impedance set-up
For instance, a 2 x 100W ampli昀椀er may be rated down
to a minimum of 4Ω on each side. However, if an 8Ω speaker
is attached to each side, the ampli昀椀er may only deliver 2
x 70W. Therefore, 70W would be the minimum handling
capacity for these speakers.
100W @ 4Ω
70W @ 8Ω
(Please refer to the instruction manual of the ampli昀椀er being
used to 昀椀nd the power output at 4Ω, 8Ω, etc)
+
8Ω _
70W
When 2 speakers are connected together in parallel
(that is “+” to “+” and “-” to “-”), the electricity from the
ampli昀椀er can 昀氀ow through 2 routes instead of one.
100W @ 4Ω
+
8Ω _
4Ω combined load
The power will be shared, so each speaker will receive 50W
(even though both are capable of handling up to 70W).
+
_ 8Ω
70W
Parallel low impedance set-up
Having twice the number of routes to 昀氀ow through
effectively, means that it is half as dif昀椀cult for the
electricity to get around the circuit. Therefore, the
impedance (resistance to 昀氀ow) is halved when 2 of the
same type speaker are linked together in parallel.
For 2 speakers with 8Ω impedance, the overall
impedance (or combined load) will be 4Ω, allowing
the 100W ampli昀椀er to deliver its full output across
this pair of speakers.
100W @ 4Ω
70W @ 8Ω
50W
+
8Ω _
50W
100W @ 4Ω
+
_ 8Ω
50W
+
_ 8Ω
50W
4Ω combined load
Standard loudspeakers comprise of 3 main components:
a cone, a magnet and a coil. Passing a current through the
coil causes the attached cone to move forward or backward.
The coil is fed the electrical signal from an ampli昀椀er, which
provides enough electricity to move the cone quickly,
causing it to vibrate and make sound.
