Why do some cars have a centre speaker? Do I need a centre speaker?

What is a centre speaker? Why do some car makers fit centre speakers?

A quick recap of what stereo sound is. Left and right being in perfect balance of phase, amplitude, frequency and time/delay creates a phantom central image of sound between the two speakers. (it makes it sound like there is a speaker in the middle, when there isn't one).

In the car this is typically the centre of the dash.

The challenge of making a hifi stereo sound is made more difficult with 4 listening positions in the car and none of them being an equal distance from the left or right speakers, sometimes there could be many more speakers.

If the car speakers cannot be placed equally apart from each listener, the next obvious solution is to put the speaker where you want the sound to come from. In the car this is typically the centre of the dash.

This concept of localisation of sound is normally considered a bad thing, you see when you have your speakers setup correctly, the speakers physically disappear, your brain does not interpret the sound as coming from anywhere but where it should from the recording. If you haven't experienced this yourself, just go with me on this. 

In case you are wondering, no it is not a simple case of fitting a speaker in the middle of the car, you need to do something with the signals going to the speakers. You need to process the sound and redirect it to the correct speaker as you now have 3, (Left, Right and Centre).

Typically when cars have this as standard they use something called an Upmixer, which reads the signal coming through for left and right channels and when it "sees" there is an equal signal going to both the left and the right channel, it stops it and redirects that signal to the centre speaker only.

*In case you are wondering, in the majority of cases, the vocal part of the mix (the vocal track) is typically placed in the centre of the sound stage and the instruments are arranged in other places (Saxaphone on the left, piano keys lowest to left and highest to right, Guitar on the right as examples).

In this article, I want to talk about the pros and cons of centre speakers and uncover why, overall, they may not be the optimal solution, they are a fix.

Pros of Centre Speakers:
1. Centre speakers exist to make sound localization easier to achieve by providing a dedicated channel for centralized sounds like dialogue and vocals.

2. With a centre speaker, a centre image is created regardless of seating position.

Cons of Centre Speakers:
1. Centre speakers can compromise tonal accuracy and EQ balance as their main purpose is to forcefully localize sound rather than achieve precise tonal finesse.

2. Distortion at Higher Listening Levels: Relying solely on a single centre speaker for centralized sounds can lead to distortion, especially at louder volume levels, negatively impacting overall audio quality as you are asking a single speaker to do the job of two speakers.

3. Limited Performance at the lower frequencies: Centre speakers often struggle to reproduce lower frequencies effectively due to their smaller size, driver capabilities and using half the cone area & power than two speakers, resulting in a deficiency of at least an octave.

4. Integration Challenges and Complexity: Integrating a centre speaker into an existing car audio system can be a complex undertaking due to space limitations, cost considerations, and potential integration issues, making the installation process more intricate.

On Balance: Why Centre Speakers Fall Short:
While centre speakers offer certain advantages, the drawbacks outweigh the benefits when it comes to achieving exceptional audio reproduction in cars. The compromised tonal accuracy, distortion at higher volumes, limited bass performance, and integration challenges render centre speakers less desirable compared to alternative approaches (doing it the right way).

What is the right way?
Instead of relying on centre speakers, a superior solution lies in harnessing the potential of high-quality digital signal processing (DSP) amplifiers and good quality speakers. These advanced systems deliver precise tonal accuracy, minimal distortion, and enhanced bass performance without the need for an additional centre speaker. By embracing the power of DSP technology and investing in good quality speakers, car audio enthusiasts can achieve unparalleled audio reproduction and a more seamless, integrated system.

If your car has a centre speaker, whilst it would be easier for us to sell you a more expensive amplifier with the additional channels to support a centre speaker, we want you to have the information to make the right choices. We think you should reconsider the reliance on centre speakers and instead consider attaining superior audio quality in your car by using the technology now available in the aftermarket. The best value for money option for most cars is the Musway M6v3, but if you want the centre speaker retained, the Audiotec Fischer Match Up8