Microphones Types & Polar Patterns Explained

In modern audio systems, microphone (also known as microphone or microphone) are the first step in sound capture and one of the most critical components in the entire audio chain. Whether used for stage performances, conference speeches, studio recordings, home karaoke, or wireless voice transmission, selecting the appropriate microphone type and understanding its directional characteristics is of utmost importance.

This article will provide a detailed introduction to the three most common types of microphone: dynamic microphone, condenser microphone, and electret microphone, including their structure, working principles, and typical application scenarios. Additionally, we will delve into the directional characteristics of microphone to help you better understand how different types of microphone perform in real-world applications.

I. microphone Types and Their Operating Principles

1. Dynamic microphone

The dynamic microphone is the most common type, widely used in live performances, handheld wireless microphone, and headset wireless microphone due to its durability and affordability.

Structure and Working Principle:  

Dynamic microphone, also known as electrodynamic microphone, have a structure similar to electrodynamic speakers.  

They primarily consist of a magnet, voice coil, and diaphragm.  

When sound waves act on the diaphragm, the diaphragm moves the voice coil within the magnetic field, cutting through the magnetic lines of force, thereby generating an induced voltage, completing the conversion from “sound energy → mechanical energy → electrical energy.”

Technical Specifications:  

Output impedance is available in two types: high impedance (1000–2000Ω) and low impedance (200–600Ω).

The frequency response is generally 30 Hz–18 kHz, with higher-quality products covering a wider frequency range.  

It has unidirectional polarity, suitable for reducing background noise interference.  

Features:  

Durable and robust, resistant to damage  

Stable operation, no external power required  

Cost-effective with high performance-to-price ratio  

Application scenarios:  

Stage performances (e.g., wireless handheld microphone used by singers)  

Presentations and teaching (e.g., wireless headset microphone)  

Voice amplification systems

2. Condenser microphone

Condenser microphone are widely used in professional recording, broadcasting, television, and film production due to their excellent sound quality, particularly in devices such as gooseneck wireless microphone and lavalier wireless microphone that require high-quality sound.

Structure and working principle:  

The core of a condenser microphone is a miniature variable capacitor consisting of a vibrating diaphragm and a fixed electrode.  

When sound waves cause the diaphragm to vibrate, the distance between the diaphragm and the electrode changes, resulting in a change in capacitance.  

Under the influence of an external DC polarization voltage, this change generates an alternating audio voltage signal across the load resistor.

Technical Parameters:  

The output impedance is capacitive and typically requires impedance matching via a field-effect transistor.  

High sensitivity, wide frequency response (up to 20Hz–20kHz), and large Dynamic Range.  

Features:  

Clear and natural sound quality, suitable for high-quality recording  

Precision construction, requires external power supply (Phantom Power or battery-powered)  

Higher cost, primarily used in professional settings  

Application Scenarios:  

Studio recording (e.g., gooseneck microphone)

Broadcasting stations (e.g., wireless microphone for meetings)

News interviews and speeches (e.g., lavalier wireless microphone)

3. Electret Condenser microphone

An electret condenser microphone is a simplified version of a condenser microphone. Due to its small size, low cost, and stable performance, it has become the most common type of microphone in consumer electronics.

Structure and working principle:  

An electret condenser microphone consists of two parts: sound-to-electric conversion and impedance conversion.  

The key component of the sound-to-electric conversion part is a plastic diaphragm with a permanent charge. After a layer of metal film is vapor-deposited on its surface, a capacitor is formed.  

When sound waves cause the diaphragm to vibrate, the electric field of the capacitor changes, thereby generating an audio electrical signal.

An internal field-effect transistor converts the high impedance of tens of megohms to an impedance level acceptable to the amplifier.

Connection configurations:  

Source-output configuration: Output impedance is less than 2kΩ, with good circuit stability and a wide dynamic range, but the output signal is relatively weak.  

Drain-output configuration: Higher gain but a narrower dynamic range.

Features:  

Compact size, easy to integrate  

No additional polarization voltage required  

High cost-effectiveness, widely applicable

Application scenarios:

Mobile phones, headset communication devices

Portable voice recorders, cassette recorders

Wireless microphone, voice-controlled switches, and other smart devices

II. Detailed explanation of microphone directional characteristics

The directional characteristics of a microphone refer to its sensitivity to sounds from different directions. Selecting a microphone with appropriate directionality can significantly improve sound pickup, reduce environmental noise interference, and effectively prevent feedback.

1. Omnidirectional  

Equally sensitive to sounds from all directions.  

Suitable for omnidirectional sound pickup in quiet environments.  

Commonly used in interviews, meeting recordings, and other scenarios where background noise does not need to be specifically isolated.  

2. Cardioid (Heart-shaped)  

Highest sensitivity at the front, slightly reduced on the sides, and almost no sensitivity at the rear.

Effectively suppresses background noise from behind and prevents crosstalk between multiple microphone.  

The most commonly used directionality in venues such as stages, KTV, and conference halls.  

Commonly found in handheld wireless microphone and headset wireless microphone.

3. Figure-8 (8-shaped)

Same sensitivity in the front and rear, with the lowest sensitivity on the sides.

Commonly used for duets, stereo recording, and other special applications.  

4. Supercardioid

Offers stronger directional focus than cardioid, with some sensitivity still present at the rear.

More suitable for noisy environments to enhance the clarity of the main sound source.

5. Hypercardioid

Even stronger directionality, focusing only on sounds within an extremely narrow angle directly in front.

Commonly used for long-distance sound pickup, such as news interviews and sports event broadcasts.

III. How to Choose the Right microphone for You?

In audio recording and sound reinforcement applications, selecting the appropriate microphone type and directional characteristics is critical. Different application scenarios have varying requirements for sound pickup direction and interference resistance. Understanding the directional characteristics and application ranges of various microphone will help improve recording quality and minimize unnecessary environmental noise interference.

1. Overview of Directional Characteristics

A microphone's directional characteristics refer to the differences in sensitivity to sounds from different directions. Based on this characteristic, microphone can be classified into omnidirectional, cardioid, supercardioid, hypercardioid, and bidirectional types, among others.

By analyzing these directional characteristic diagrams, we can determine a microphone's sound pickup capability in specific directions. For example, when using a handheld wireless microphone in a stage performance, a dynamic microphone with a cardioid directional characteristic is typically chosen to focus on capturing vocals while reducing surrounding noise interference; whereas lavalier wireless microphone or gooseneck wireless microphone used in news interviews may adopt supercardioid or superdirectional designs to clearly capture speech from a distance.

2. Proximity Effect

The proximity effect refers to the phenomenon where certain directional microphone (such as cardioid or supercardioid) exhibit enhanced low-frequency response when positioned close to the sound source. This effect can make the sound appear richer but may also cause Distortion or blurring.

In practical applications, for example, when using a headset wireless microphone for live streaming or karaoke, if the distance from the mouth is not properly controlled, a noticeable low-frequency boost may occur. Therefore, when selecting such microphone, it is important to consider whether they have the ability to control the proximity effect or to adjust the pickup distance appropriately based on usage requirements.  

3. How to choose the most suitable directional microphone?  

The most suitable directional microphone should be selected based on the specific application scenario and recording objectives:  

Cardioid directional microphone are suitable for speeches, stage performances, and other scenarios where it is necessary to focus on sounds from the front while suppressing background noise;

Supercardioid/hypercardioid microphone are suitable for long-distance sound pickup, such as sports event broadcasts and news interviews;

Omnidirectional microphone are suitable for recording sounds from multiple directions, such as live music performances and meeting recordings;

Bidirectional microphone are commonly used for two-person interviews or stereo recordings.

Selecting the appropriate directionality based on the application scenario not only improves sound clarity but also effectively reduces crosstalk and feedback issues.

4. How is directional characteristics formed?

The directional characteristics of a microphone are primarily determined by its internal acoustic structure and microphone array design. By controlling the different paths through which sound waves enter the microphone or using multiple microphone units in combination, selective reception of sounds from different directions can be achieved.

For example, some high-end wireless conference microphone use an array system composed of multiple miniature microphone to enhance sound recognition capabilities in specific directions, thereby achieving stronger directional control.  

5. Advantages of omnidirectional microphone  

Omnidirectional microphone have the same sensitivity to sounds from all directions, enabling uniform sound pickup without precise alignment with the sound source. This characteristic makes them ideal for multi-source environments such as conference rooms, classroom recordings, or small band performances.

Additionally, omnidirectional microphone are less affected by the proximity effect, resulting in more natural and balanced sound reproduction. In environments requiring stable, long-term recording, such as remote meetings or podcast recordings, omnidirectional microphone are an ideal choice.

When selecting a microphone, it is important to consider not only its type (e.g., dynamic, condenser, electret) but also to match its directional characteristics appropriately to the usage scenario. Whether it is a handheld wireless microphone for stage performances, a lavalier wireless microphone for interviews, or a gooseneck wireless microphone for conference systems, understanding the directionality, proximity effect, and formation principles of microphone will help you achieve a superior audio experience.

Click to view more details The 7 Types of microphone Explained

Ⅳ. Summary

Each type of microphone has its unique advantages and suitable applications:

Dynamic microphone are simple in structure and durable, making them suitable for live use;

Condenser microphone offer excellent sound quality, making them suitable for professional recording;

Electret microphone are compact and cost-effective, making them suitable for consumer electronics devices;

The choice of directionality determines whether the sound pickup is clear and free from interference.

Whether you are looking for a handheld wireless microphone, lavalier wireless microphone, headset wireless microphone, gooseneck wireless microphone, or conference wireless microphone, understanding these basics will help you make a more informed choice.