# 5.9 How do I wire speakers "in series" and "in parallel?" [IDB]

## Description

This article is from the Car Audio
FAQ, by Ian D. Bjorhovde (ianbjor@mobileaudio.com) with
numerous contributions by others.

# 5.9 How do I wire speakers "in series" and "in parallel?" [IDB]

Wiring speakers in series involves connecting at least two speakers so

that the first speaker's positive lead is connected to the amplifier's

positive terminal, and the negative lead is connected to the positive

lead of the second speaker. If there is a third speaker, its positive

lead will be connected to the second speaker's negative lead ... and so

on. The last speaker in the chain will have its negative lead

connected to the amplifier's negative terminal.

Speakers that are wired in parallel are all connected to the positive

and negative terminals of the amplifier. So, when two speakers are

wired in parallel, you'll connect each speaker's positive lead to the

amplifier's positive terminal, and you'll connect each speaker's

negative lead to the amplifier's negative terminal.

Be careful when wiring multiple speakers in parallel or series so that

you do not exceed your amplifier's rating. To calculate the effective

impedance of a number of speakers, use the following formulas:

Series Connections:

Z(t) = Z(1) + Z(2) + Z(3) + ... + Z(n)

That is, add up all of the impedances for each speaker to

get the total impedance. For example, with 3 4-ohm speaker

in series, the total impedance is 4 + 4 + 4 = 12 ohms.

Parallel Connections:

1/Z(t) = 1/Z(1) + 1/Z(2) + 1/Z(3) + ... + 1/Z(n)

That is, add up the inverse of the impedance of each

speaker and invert the sum to get the total impedance. For

example, with 3 4-ohm speakers in parallel, the total

impedance is 1 / ( 1/4 + 1/4 + 1/4) = 1 / (3/4) = 1.33 ohms.

Continue to: