Good sound quality is essential to any audio setup, from home theatre systems to live sound PA. An important factor in producing good sound quality is speaker phase. Speaker phase is often overlooked but can have an enormous impact on the overall sound of a speaker system.
Speaker phase refers to the timing of the signal being sent out of a speaker. When two speakers are in phase, each one is receiving the same signal and sends it out at exactly the same time. If they are out of phase, then one of them will send out its signal after the other.
This can cause a cancellation effect, meaning that the sound waves created by one speaker will cancel out the sound waves created by the other. This can cause a muddy or distorted sound.
In this article, I will cover what speaker phase means and why it’s important, covering:
- What does speaker phase mean?
- Why is speaker phase important?
- How do I tell if my speakers are out of phase?
- What do speakers out-of-phase sound like?
What Does Speaker Phase Mean?
Speaker phase is an important aspect of speaker operation that can have a significant effect on sound quality in your speaker setup.
Speaker phase is the relationship between two or more speakers and how they interact with each other when playing audio. If the speakers are in phase, the sound waves from each speaker will arrive at the same time and combine to produce a single, unified audio signal.
But if the speakers are out of phase with one another, then their sound waves will arrive at different times, causing them to cancel each other out and create distortion or cancellation of the audio signal. This is why it’s important to ensure that speakers are properly set up so they are in phase.
In a speaker, the cone or diaphragm moves forward and back to create sound. This produces sound waves, as shown in the following image:
If you have two speakers and the cones are moving in the same direction at the same time, they are said to be in phase, as per the image below.
If the cones are moving in opposite directions, we say that the speakers are out of phase. Below is an image of two speakers that are out of phase.
To understand why this is a problem for audio quality, we need to understand how two sound waves interfere with each other.
When you have two sound waves, the phase of both waves sum to give a result. So what does this mean?
Let’s look at the image below. We have two speakers that are in phase. This means that the cones are moving in the same direction at the same time.
I show the sum of these two waves in the output signal in the following image. The amplitude of the two sound waves from each speaker will combine to create a sound wave which will have double the amplitude.
When the sound waves from the two speakers are 180deg out of phase, when the amplitude of these two sound waves is summed, you see they cancel each other, producing no output in theory.
For higher-frequency sound waves, this might not be so noticeable, but for bass frequencies, this is a real problem.
If you experiment with the phase settings on your speakers, you’ll probably notice that your bass sound decreases as your speakers fall more and more out of phase.
Why Is Speaker Phase Important?
Speaker phase is a technical concept that has an important impact on the sound quality of audio equipment. It refers to the timing of when different speakers in an audio setup play the same signal and they need to be synchronised. When they are not, it can create a number of problems, from sound distortion to reduced loudness.
The most common reason for speaker phase issues is incorrect wiring. When you connect speakers improperly, it can cause them to be out of phase (also known as “reverse polarity”), which means the sound waves are inverted and thus cancelled out when they reach your ears. This results in a muffled or distorted sound with little bass response.
Another issue can arise when connecting speakers in a stereo setup. If one speaker is out of phase relative to the other, it can cause sound cancellation and diminish the overall sound quality. It can also lead to decreased stereo imaging (the illusion that sounds are coming from different sources) and reduced loudness.
So it’s essential to get the phase right when setting up a stereo system.
Finally, speaker phase can also affect how sound travels through an acoustic environment. If speakers are out of phase in one part of the room and in phase in another, it will create standing waves and resonate at certain frequencies, resulting in an uneven frequency response.
In short, speaker phase is an important concept to consider when setting up a sound system. It can have a profound impact on the overall sound quality and should be taken into account when setting up the optimum listening experience. Getting it right will ensure that you get the most out of your audio equipment.
How Do I Tell If My Speakers Are Out Of Phase?
As mentioned, speaker phase is an important concept to understand when setting up speakers for optimal sound quality.
A speaker’s phase can affect the overall sound of a system, and if out of phase, can cause a distorted or muffled sound. Knowing how to tell if your speakers are out of phase is essential for getting the best sound from your system.
One way to tell if your speakers are out of phase is by listening for a cancelled out, hollow sound. If you find that one channel sounds louder than the other or one channel is lacking quality overall, then your speakers may be out of phase.
You can also use a polarity tester to determine if your speakers are in or out of phase. Polarity testers are designed to detect if a speaker is out of phase, and they can ensure that both speakers in a system are in phase with one another.
Why Are My Speakers Phasing?
The most common reason for speakers being out of phase is because of incorrect wiring.
Typically, every speaker will have two inputs: a positive and a negative terminal.
Often these terminals will be coloured red for positive or black for negative.
If there is no colour code used, then positive and negative will most likely be written on your speaker, or some other form of labelling will be used on the speaker wire.
When the speaker is correctly wired, i.e. the positive terminal of the speaker is connected to the positive input of the signal, the speaker cone will move forward first.
“Moving forward” means that the cone will move towards you if you are looking at it head-on.
Of course, when you are listening to high-frequency audio this is really hard to see and after a while, from visually looking at the movement of a speaker, you will start to question what direction the speaker cone is actually moving as your eyes play tricks on you.
Below is a really simple and effective test to tell if your speakers are out of phase from Axiom Audio. From all the advice I have seen, from phase apps to using signal generators and oscilloscopes, this video has the most simple and effective solution.
What Do Speakers Out Of Phase Sound Like?
Speakers out of phase will sound strange and hollow. The sound waves being produced by the speakers will cancel each other out, leading to an overall decrease in bass frequencies and a reduction in perceived volume.
In some cases, you may also hear a faint rhythmic popping or swishing noise as the opposing sound waves interact with one another.
Additionally, if your left and right speakers are out of phase, you may find that dialogue is difficult to understand since the two speakers’ vocal ranges are cancelling each other out, too.
You might also experience issues with stereo imaging where it feels like sounds are coming from anywhere but their intended source.
Speaker phasing problems will be more pronounced on certain frequencies compared to others, with bass and treble sounds being affected more than mid-range frequencies.
It can also affect stereo imaging, making it difficult to distinguish left and right channels in the mix. This can lead to an overall feeling of mono-like tonality coming from the speakers rather than stereo presence, which would otherwise be present if they are properly phased.
In conclusion, speaker phase is an important factor when it comes to getting the best sound out of your speakers.
If your left and right channels are not in sync with each other, you’ll likely experience a decrease in bass frequencies and stereo imaging, as well as difficulty understanding dialogue.
To ensure that your audio system is properly phased, check for signs of mis-phasing such as strange hollow sounds or faint rhythmic popping noises.
With larger woofers, it may be possible to physically inspect the cones to see if they are moving in different directions, however, this can be difficult to monitor. Using a polarity tester or even a phase-testing phone app can be an easier way to check your speaker phase.
With proper phasing setup, you can ensure that you are enjoying the best sound from your system.