What Is Speaker Distortion? (And how is it measured)

In the realm of audio technology, the term ‘speaker distortion’ often conjures mixed feelings among enthusiasts and novices alike. This phenomenon, essentially a deviation in the output signal compared to the input, can be both a blessing and a curse, depending on its nature and severity.

Speaker distortion refers to the unwanted alterations in sound produced by a speaker system. It occurs when the speaker fails to reproduce the input signal accurately, resulting in a distorted and muddied sound output.

Common causes of distortion include overloading, clipping, and nonlinear response in the speaker components.

In this article, I will explain what speaker distortion is and consider whether speaker distortion can ever truly be considered a good thing.

a broken hi fi speaker

What Is Speaker Distortion?

Speaker distortion, in its simplest terms, can be defined as the deviation or alteration of an audio signal that results in a sound output that’s different from the original input. It usually occurs when your speakers are unable to reproduce the sound that they’re fed accurately, leading to a corrupted audio output.

The corruption can manifest in several ways, but the most common are clipping, where the tops and bottoms of the waveforms are cut off, and overloading, where the speakers are pushed beyond their capacity to handle the power they’re receiving.

Both result in an audio output that’s harsh, unpleasant, and far from the original intent of the recording.

Like all things with audio and speakers, however, the explanation is never that simple and straightforward. We cannot say that all speaker distortion is bad, as there are different types of distortion. Some speaker users, like Guitartis, for example, might like some of the “right type” of distortion from their speakers.

What Are The Different Types Of Speaker Distortion? 

Distortion in speakers generally falls into two main categories: linear and nonlinear distortion.

1. Linear Distortion

Linear distortion occurs when all frequencies are not amplified equally. In simple terms, some parts of the sound spectrum might get louder while others remain the same. This can lead to an imbalance in the overall sound output, causing certain frequencies to overshadow others.

2. Nonlinear Distortion

Nonlinear distortion, on the other hand, occurs when the speaker changes the shape of the audio waveform. This can happen due to the speaker’s limitations, like when it’s being driven too hard or incapable of producing certain frequencies. The most common types of nonlinear distortion are harmonic and intermodulation distortion.

Harmonic distortion happens when the speaker generates harmonics that were not present in the original signal, while intermodulation distortion is caused by the interaction between different frequencies in the signal, creating additional, undesired frequencies.

Both types of speaker distortion can affect the sound’s quality and the overall listening experience. It’s important to understand the distinction to diagnose issues with your audio setup properly and make well-informed decisions about your audio equipment.

The Difference Between Linear And Nonlinear Distortion

The key difference between linear and nonlinear distortion lies in the way they alter the audio signal. 

Linear distortion, as mentioned before, involves unequal amplification of different frequencies. This means that certain frequencies become louder while others remain the same, causing an imbalance in the sound output. This type of distortion doesn’t add new frequencies to the signal and is often easier to correct through equalization or filtering.

Nonlinear distortion, however, involves a change in the shape of the audio waveform and often introduces new frequencies that weren’t in the original signal. This type of distortion is much harder to correct because the distorted signal contains components not present in the original signal. 

Whether it’s harmonic distortion, which involves the generation of harmonics not present in the original signal, or intermodulation distortion, caused by the interaction between different frequencies, nonlinear distortion can significantly degrade the quality of sound.

In essence, while linear distortion affects the ‘balance’ of the sound, nonlinear distortion affects the ‘purity’ of the sound. Both can degrade the audio experience, but in different ways and to different extents, depending on the severity and the listener’s perception.

What Is Total Harmonic Distortion?

Total Harmonic Distortion (THD) is a measure used in audio systems to quantify the level of harmonic distortion present. It is a key aspect of assessing sound quality, and understanding it can help improve your audio experience.

Total Harmonic Distortion (THD) occurs when harmonics —frequencies that are multiples of the original signal frequency—are produced by the audio system. These additional frequencies distort the original signal and are generally perceived as a harsh, less natural sound.

In technical terms, THD is expressed as a percentage of the overall signal that is made up of these harmonic distortions, compared to the original, undistorted signal.

Higher percentages indicate greater distortion and, thus, lower sound quality. Therefore, in audio equipment specifications, a lower THD is usually desirable as it means the reproduction of the audio signal is more accurate.

What Do We Mean By Clipping?

‘Clipping’ is a form of distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. When this happens, the peaks of the audio signal exceed the amplifier’s power capacity, causing the tops and bottoms of the waveforms to be ‘clipped’ off.

This not only alters the waveform but also creates additional frequencies not present in the original signal, leading to a harsh and degraded sound output.

It’s like trying to fit a square peg into a round hole – the corners are going to get sliced off. 

Clipping can not only damage the sound quality but also potentially harm your speakers, as it often results in the speaker cones moving in ways they were not designed to handle.

Why Do Speakers Distort?

Speakers distort primarily due to two main reasons: overpowering and underpowering.

Overpowering happens when the amplifier delivers more power than the speaker’s capacity, causing the voice coil to move beyond its limit and resulting in a distorted sound. This is often the case when the volume is turned up excessively high.

On the other hand, underpowering, also known as ‘clipping’, occurs when the amplifier can’t deliver enough power in an attempt to produce the desired volume; the amplifier clips off the peaks of the sound wave, which also leads to distortion.

In addition to these, poor-quality components, incorrect settings, and faulty wiring can also contribute to speaker distortion. It’s essential to ensure that your audio system is appropriately matched and configured to prevent unwanted distortion and preserve the quality of sound.

Is Speaker Distortion A Good Thing?

Whether speaker distortion is considered a ‘good’ thing is largely subjective and depends on the listener’s preferences and the context. In certain situations, some forms of distortion can actually contribute positively to the sound.

For instance, in the world of music production, specifically in genres such as rock and blues, distortion is often intentionally used to add a certain ‘grit’ or ‘warmth’ to the sound, enhancing the musical piece’s emotional impact. Guitar amplifiers are frequently designed to introduce a degree of distortion to achieve a desired tonal character.

However, from a purely technical perspective, distortion represents a deviation from the original sound signal and, therefore, a loss of audio fidelity.

High levels of distortion can lead to a harsh, unclear sound that most would consider undesirable, especially in a high-fidelity audio system designed for accurate sound reproduction.

So, while some may find a certain charm in the colouration added by distortion in guitar speakers, in general, for the objective of achieving the truest representation of the original audio signal, distortion is usually considered a detrimental factor.

What Is The Difference Between Good And Bad Speaker Distortion?

As a guitarist, I love a bit of distortion, but when is distortion good, and when is it bad?

The distinction between ‘good’ and ‘bad’ speaker distortion is largely subjective and context-dependent. 

Good distortion, often seen in the realm of music production, adds a desired warmth, grit, or tonal character to the sound. For instance, electric guitar tones in rock and blues often leverage distortion to create a distinctive, powerful sound that enhances the music’s emotional impact. This kind of distortion is intentional and artistically valuable—it enriches the listening experience rather than degrading it.

On the other hand, bad distortion refers to any unintentional alteration or degradation of the original audio signal that results in a loss of fidelity or clarity. This usually occurs due to technical shortcomings in the audio equipment, such as overdriving an amplifier or underpowering a speaker.

Bad distortion adds frequencies not present in the original signal, leading to a harsh, unnatural sound. In severe cases, it can even cause physical damage to the speakers.

Thus, while some listeners might appreciate the colouration added by ‘good’ distortion, ‘bad’ distortion is generally seen as detrimental to the audio experience.

Does Speaker Distortion Damage Speakers?

Speaker distortion can indeed cause damage to speakers, especially in cases involving clipping and overpowering. When an amplifier is overdriven beyond its capabilities and the peaks of the signal waveform are clipped, it can result in the speaker cones moving in ways they were not designed to, potentially leading to mechanical damage.

Overpowering, on the other hand, can strain the speakers by forcing the voice coil to move beyond its limit, resulting in overheating and eventual burnout.

Poor quality components and faulty wiring can also exacerbate these problems. However, while distortion can be harmful to speakers, proper use and maintenance of your audio system can significantly reduce the risk.

How Do You Fix Speaker Distortion?

Fixing speaker distortion involves a few steps and considerations. First, identify the source of distortion – the issue could lie with the amplifier, the wiring, or the speakers themselves. If the sound distorts when you turn up the volume, the amplifier may be the issue – you might be overloading it, or it could be underpowered. Try reducing the volume to see if the distortion persists.

Check the speaker wires for any signs of damage or loose connections and ensure they are correctly installed. Poor wiring can often lead to sound distortion. 

Also, consider the quality of your components. Low-quality speakers or amplifiers are more prone to distortion, so investing in quality audio equipment can significantly reduce distortion.

If you’re using an equalizer, ensure it’s set appropriately. Excessively boosting the bass or treble can cause distortion, so start with a flat EQ setting and adjust gradually to your preference.

Lastly, if you’re using a digital source, ensure the audio files are of high quality. Compressed files can lead to a loss of audio data, which may result in distortion.

Remember, maintaining your audio equipment and using it within its limits will help prevent distortion and potential damage. If these steps do not resolve your issue, consider consulting an audio professional in your area.

How Do You Measure Speaker Distortion? 

Measuring speaker distortion involves using specific tools and techniques aimed at assessing the audio output quality. One common method is the Total Harmonic Distortion (THD) measurement, which quantifies the degree to which the sound output deviates from the original input signal. THD is expressed as a percentage, with lower values indicating less distortion and higher fidelity.

You can measure THD using a spectrum analyzer, a device that plots the frequency spectrum of an audio signal. By comparing the input and output signals, the analyzer identifies and measures the amplitude of additional harmonic frequencies—distortions—introduced by the audio system.

Additional software tools, like Room EQ Wizard and Audacity, provide accessible ways to measure distortion from your computer. They generate pure tone signals, measure the output from your speakers, and analyze the results for distortion.

This article from Audio Judgement has great information on how to measure distortion in audio systems [source]

Remember, while measuring speaker distortion can help optimize your audio system, it’s also crucial to trust your ears. High-fidelity sound is ultimately about your personal listening experience.

Why Do My Speakers Sound Distorted?

Your speakers might sound distorted for several reasons. The primary cause could be the overdriving of an amplifier, which can lead to clipping and result in distorted sound.

Similarly, if your speakers are underpowered, it may strain the system and cause distortion.

Faulty or loose wiring can also affect the quality of sound, leading to a distortion that often gets misunderstood as a speaker problem.

Lastly, the quality of the audio source can immensely impact the resulting sound. Compressed or low-quality audio files might lack the necessary data for high-quality sound reproduction, leading to distortion when played through even the best speakers.

Remember, maintaining your audio equipment and using it within its limits will help prevent distortion and potential damage.

Regularly check your wiring, ensure your amplifier is not under or overpowered, and always use high-quality audio files for the best audio experience.

Final Thoughts

Speaker distortion, while generally perceived as detrimental, can sometimes be a sought-after effect, particularly in certain genres of music. However, excessive or unwanted distortion can lead to poor audio quality and, in severe cases, damage to your speakers.

Understanding the types of distortion, notably linear and nonlinear, and their causes, such as overdriving an amplifier or poor-quality components, is vital in diagnosing and addressing the issue.

Moreover, knowing how to measure distortion using tools like a spectrum analyzer or software tools can be invaluable in optimizing your audio system for the best possible sound quality.

Lastly, remember that prevention is the best cure—proper maintenance, use within limits, and investment in high-quality audio equipment can significantly mitigate the risks and impacts of speaker distortion.

Engineer Your Sound

We love all things audio, from speaker design, acoustics to digital signal processing. If it makes noise, we are passionate about it.

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