Understanding Distortion in Microphones

Content Summary

This article provides a detailed introduction to Distortion, explaining its causes in accordance with the national standard GB/T 2900.86-2009, and analyzing its specific manifestations in dynamic microphones, condenser microphones, and wireless microphones.

By integrating content from “Fundamental Frequency Analysis,” “Frequency Response Analysis,” and “Sound Power Level Analysis,” it explains the impact of distortion on audio quality and how to reduce distortion through technical means to enhance the overall performance of audio systems.

Distortion: An Unavoidable “Sound Deformation” Issue in Audio Systems

Understanding Distortion in Microphones

In audio engineering, “distortion” refers to unwanted changes in the sound waveform. It not only affects sound quality but may also lead to unclear speech, loss of musical authenticity, or even compromise the overall effect of live performances or recordings.

According to the national standard GB/T 2900.86-2009 definition 801-21-48, distortion may be caused by the following factors:

a) Non-linear relationships between input and output

b) Uneven transmission at different frequencies

c) Phase shift not proportional to frequency

This article will analyze distortion in microphone systems from an electroacoustic perspective, examining its manifestations and effects on different types of microphones. It will also draw on knowledge from “Fundamental Frequency Analysis,” “Frequency Response Analysis,” and “Sound Power Level Analysis” to help you gain a more comprehensive understanding of this critical audio parameter.

1. What is distortion? How is it produced?

1. Basic definition of distortion

Distortion refers to unexpected changes between the input signal and the output signal. In other words, it is the distortion of the original clear and accurate sound after it has been processed by a microphone or audio system.  

For example:  

The singer's originally clear high notes become harsh and piercing;  

The low notes become blurred and unclear;  

The human voice sounds as though it is “through a layer of paper”;  

These could all be consequences of distortion.

2. The Three Main Causes of Distortion

a) Non-linear Response  

This is one of the most common sources of distortion. When the output of a microphone or speaker does not maintain a consistent proportional relationship with the input, this type of distortion occurs.  

For example:  

Some dynamic microphones experience magnetic saturation at high Sound Pressure Levels;  

This causes the output signal to “clip,” resulting in Harmonic Distortion (Harmonic Distortion);

b) Frequency-dependent Gain  

If a device amplifies certain frequencies more than others, it can cause tonal imbalance.  

For example:  

Some low-end microphones have weaker response in the low-frequency range;  

causing male voices to sound “muted”;  

or overly prominent high-frequency response, making female voices sound “harsh”;

c) Phase Distortion  

When signals of different frequencies pass through the device, their time delays differ, causing phase misalignment, making the sound “muddy” or “unnatural.”  

This is particularly common in wireless microphone systems, especially in environments with severe multipath interference.

2. Manifestation and Impact of Distortion in Different Microphone Types

While all microphones are susceptible to distortion, differences in structure and operating principles among various product types result in varying degrees of distortion performance.

1. Dynamic Microphones and Distortion

Dynamic microphones are renowned for their durability and strong noise resistance, but they may also produce distortion under extreme conditions.

a) Non-linear distortion in high Sound Pressure environments  

The connection between the diaphragm and coil in dynamic microphones can cause magnetic saturation when exposed to extremely high sound pressure levels (e.g., close-miking drum kits or guitar amplifiers).  

Results:  

The output signal is “clipped”;

producing a noticeable “clicking” sound or harshness;

b) Frequency Distortion caused by frequency response limitations

Dynamic microphones typically excel in low-frequency response but may lack clarity in the high-frequency range.

Mr Senma S-ONE Dynamic Vocal Microphones

For example:

The Shure Mr Senma S-ONE has a frequency response range of 60 Hz – 16 kHz;

For vocals or string instruments with rich overtones, some details may be lost;

2. Condenser Microphones and Distortion

Condenser microphones, with their high sensitivity and wide frequency response, are widely used in recording studios and professional settings. However, due to their complex internal circuitry, they are more susceptible to electronic noise and overload.

a) Clipping distortion caused by overload

If the preamplifier of a condenser microphone lacks proper protection design, it may experience clipping under high sound pressure input.

Mr Senma U87S large diaphragm condenser microphones

For example:  

When recording plosive sounds (such as “P” or “B”);  

If a pop filter is not used;  

This may cause instantaneous overload, resulting in noticeable distortion;  

b) Harmonic distortion caused by high-frequency response  

Condenser microphones can capture higher-frequency harmonic components, but if not handled properly, they may introduce unwanted harmonics.

For example:  

When a female singer sings high notes;  

If the microphone is overly sensitive to high-frequency response;  

This may make the sound harsh;

3. Wireless microphones and distortion

Wireless microphones must not only deal with traditional distortion but also interference and compression issues during wireless transmission.

a) Signal distortion caused by radio frequency interference

Wireless microphones operate in the UHF or VHF frequency bands. If there are other wireless devices nearby (such as Wi-Fi, Bluetooth, or walkie-talkies), this may cause signal interference.

Mr Senma U4 Four channel Professional Wireless Microphone

For example:  

At large-scale events;  

Multiple wireless microphones used simultaneously;  

If channels are improperly configured;  

This may result in frequency interference or signal dropouts, manifesting as fluctuating volume levels, hoarseness, or intermittent sound;  

b) Dynamic Range compression distortion caused by compression algorithms  

To conserve bandwidth, some wireless systems use compression encoding, which may cause sound to become “flat.”

For example:  

When recording podcasts using a Bluetooth microphone;  

If the encoding quality is low;  

Some dynamic details may be lost;  

Resulting in a lack of layering in the sound quality;  

3. How to reduce distortion in microphone systems?  

1. Choose high-quality microphones and accessories  

Use microphones with wide frequency response and low Total Harmonic Distortion (THD);  

Pair with high-quality pop filters, shock mounts, and preamplifiers;

Ensure stable power supply to avoid voltage fluctuations affecting audio quality;

2. Control the input sound pressure level (SPL)

Avoid positioning the microphone directly facing high-SPL sources (such as close-miked drum kits or speaker cabinets);

Use the pad function to reduce input gain;

Adjust the distance appropriately to control pickup intensity;

3. Optimize the wireless transmission environment  

Use the radar frequency scanning function to automatically avoid interference bands;  

Set reasonable channel intervals to prevent interference between multiple systems;  

Ensure there are no obstacles blocking the transmitter and receiver;  

4. Distortion is the “invisible killer” of audio systems and must not be ignored  

Whether it is a dynamic microphone, condenser microphone, or wireless microphone, distortion is an important factor affecting sound quality.

From the stability of the fundamental frequency to the integrity of the frequency response, and the accuracy of the sound power level, every step can be a source of distortion. Only through scientific selection, proper use, and good maintenance can distortion be minimized to restore true, clear, and natural sound.

As a professional Microphone Manufacturer, we have fully considered distortion control mechanisms in the product design stage to ensure that every product delivers exceptional audio performance in various usage scenarios.