Series vs Parallel Subwoofer

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Updated October 26, 2022

Those venturing into home theatres must understand that research is required to get the best speakers. From selecting a correctly powered amp to narrowing in on the best subwoofer, everything from the Ohm load to the wiring configuration needs examining. While you’ll need more than just one article to get the full rundown, below, we’re tackling one of the most fundamental pieces of the speaker setup process as we compare series vs parallel subwoofer wiring connections.

KEY TAKEAWAYS:

  • Selecting the proper wiring setup is crucial to optimizing overall sound and ensuring you don’t damage your amplifier.
  • A series wiring increases speaker impedance by creating a single line of electric current: connecting the positive terminal output to the next speaker’s negative terminal input.
  • Parallel wiring decreases impedance by creating multiple paths of electrical current.

We get that the journey is long and winding, but we’re here to help. For more, read up on the differences between passive vs active subwoofers. And for a great buying guide, we have a list of the best wireless speakers.

Differences Between Series vs Parallel Subwoofer Wiring

So, how does the pattern of the wires affect the sound? A wire’s a wire, right? Just connect it, and bam! Let there be sound.

Not quite.

Insider Tip

Some amps have an automatic turnoff function if they feel overheating due to imbalanced impedance levels.

There are two main wiring options: series and parallel. Your choice determines the amount of power released from the stereo amplifier. But before we can even dip a toe into comparing the two, it’s necessary to understand how a speaker works.

The amplifier connects to a speaker, providing power that flows through the copper voice coil. The voice coil takes the amp’s energy and moves the speaker cone, which pushes the air, creating sound.

Every voice coil has what’s called a resistance rating. This rating determines how much electrical current the speaker can handle, and the resistance is calculated in Ohms. Likewise, an amp also has an Ohm rating. So why does this matter?

When a speaker and amp’s impedance levels are incompatible — for example, the speaker has a lower impedance than the amp’s output; this causes overheating because the amp is trying to push out more power than it can give off. The result can be a total failure and cause irreparable damage.

Mostly, it’s easy to calculate the proper power output when working with one subwoofer. However, you must wire them together when adding two or more. And this is where series and parallel come into play.

The difference lies in how the speakers are connected from their negative and positive terminals. Series wiring means each speaker’s positive connection is wired to the next speaker’s negative connection. Series creates one continuous line of electrical current.

On the other hand, parallel wiring reverses this and creates multiple paths of current. Every speaker in a parallel chain has its positive terminal connected to the positive terminal of the following speaker.

The result? Totally different ways of calculating the power rating of the speaker setup.

Series wiring is easy because, with every added speaker, you add the impedance load together, i.e., two 4-Ohm speakers create an 8-Ohm impedance.

However, in parallel wiring, the speaker impedance lowers depending on the Ohm load of each speaker. To do this accurately, you can use an online calculator; for example, two 8-Ohm speakers create a 4-Ohm load.

And that’s series and parallel. Now, for the more important question, how does each setup affect the volume and sound quality?

And guess what? The series/parallel choice isn’t even the last connection decision you’ll have to make. Subwoofer owners must be aware of high-input vs low-input subwoofer connections as well.

Power & Volume

Choosing to wire your speakers in series or in parallel all hinges on maximizing the output of the amplifier. Therefore, it all depends on what best matches the speakers and amplifiers Ohm loads. From there, you can determine which is best because, technically, either wiring can optimize sound.

However, given that a series wiring increases resistance, it’s likely true (but not always) that parallel will give more power and volume.

Warning

Connecting speakers with a series wiring scheme increases your amplifier’s likelihood of burning out.

Bass Sound Quality

Sound nuts often peer over their noses at series wiring because it leads to less power and lower audio quality in most cases, including subwoofers. However, as stated before, it depends on maximizing the amplifier’s power output.

Another spec that users should consider when attempting to optimize sound quality is if they should buy a wired vs wireless subwoofer.

Convenience & Safety

Series wiring schemes are much easier to set up than parallel, given that the wiring looks the same for each speaker within the chain.

STAT: Subwoofers use around 150 to 1,000 watts, depending on the unit, to create bass sound. (source)

Likewise, because it series waiting for increased impedance, there’s a much greater chance that the setup will damage the amplifier.

Series vs Parallel Subwoofer FAQs

Which wiring setup is better for a 2-Ohm speaker?

As stated, speaker-to-amp wiring all depends on the amplifier's Ohm load.

What is the best wattage for a subwoofer?

The wattage depends first on the amp output. Then, you have to consider the speaker's space and if it matches the size and acoustics of the room and accompanying speaker setup.

Do you have to wire four speakers in parallel?

No, so long as the impedance of speakers works with the amp output when connected, you can do either a series or parallel wiring.
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