How to Wire Speakers in Parallel & Series, and how does it affect Impedance?

There are a number of ways that speakers can be wired, but the most commonly used are Parallel and Series. These are also the two ways in which our speaker systems are based upon and is what you will use when installing them.

You can also combine series and parallel wiring to achieve a desired impedance, which will be explained further below.

It’s important to wire speakers correctly based on the specifications of the amplifier and the number of speakers, as this will ultimately provide the best sound quality and avoid possible damage to the equipment.

In simple terms, impedance refers to the load a speaker places on the amplifier. More specifically, it’s how much the speaker resists current. The lower the impedance (measured in Ohms Ω), the more power the speaker will draw from the amplifier.

This is why wiring in the correct manner is important, as you want to avoid overloading the amplifier.

If an amplifier is rated at 4 Ohms minimum, then you want to ensure the overall load created by the speakers does not go below this. If it does, the speakers will be drawing more power than the amplifier can provide, which will lead to a subpar or even distorted sound, and can permanently damage the amplifier.

Parallel wiring is the most common and simplest way of wiring. All it involves is combining the positive leads (+) together, and the negative leads together (-). This can be achieved by simply plugging all speakers individually into the same corresponding terminals on the amplifier, or by connecting the speakers together.

The benefit of parallel is you don’t need to loop any cable back to the amplifier. Once the last speaker is connected, you can terminate the wiring at that point.

How does this affect Impedance?

Wiring in parallel reduces the impedance. This is calculated by dividing the number of speakers by their impedance. For example:

• 2x speakers @ 8Ω = 4Ω
• 2x speakers @ 16Ω = 8Ω
• 4x speakers @ 16Ω = 4Ω

When wiring in series, you connect the negative (-) terminal on the first speaker to the positive (+) terminal on the next speaker in the chain. This can be repeated to more speakers as necessary.

On the final speaker, the remaining negative (-) cable will be routed back to the amplifier.

The end result will leave you with a positive (+) cable from the first speaker, and a negative (-) cable from the final speaker in the chain plugged into the amplifier.

How does this affect Impedance?

Wiring in series increases the impedance. This is calculated by multiplying the number of speakers by their impedance. For example:

• 2x speakers @ 8Ω = 16Ω
• 2x speakers @ 4Ω = 8Ω
• 4x speakers @ 4Ω = 16Ω

A combination of Series/Parallel wiring can be used to achieve a desired impedance where applicable. This method isn’t very common but can be used in situations with a lot of speakers, or on amplifiers with a small number of channels.

Series/Parallel wiring consists of wiring multiple groups of speakers in series, with each group then connected to the amplifier in parallel.

How does this affect Impedance?

Wiring in series/parallel will either reduce, increase, or keep the impedance the same depending on how it’s wired. The overall load is calculated by working out the impedance on each group connected in series, divided by the number of groups connected in parallel. For example:

• 8x speakers total @ 8Ω each
• 4x pairs wired in series (four lots of two) = 4x 16Ω groups
• 4x 16Ω groups wired in parallel = 4Ω load total.