• You want to know about microphones used in field recording.
  • You’re considering buying a microphone but don’t know which one to choose.
  • You want to know the best microphones for beginners.

This article covers everything you need to know about microphones for field recording.

barbe_generative_diary SOUNDS – Field Recording

I began field recording as part of a project called “Sound Visualization,” which involved capturing sound materials for creating program art. Since then, I’ve become fascinated by various environmental sounds and have continued to learn about recording techniques and editing on my own.

Index

Chapter 1 – Microphones and Their Types

A microphone is a device that converts sound into electrical signals. There are various types of microphones, but the two main ones are dynamic microphones and condenser microphones.

Dynamic Microphones:
Dynamic microphones convert sound vibrations in the air into electrical signals via a diaphragm. Their simple construction makes them durable and resistant to humidity and high temperatures. They do not require an external power source and are relatively inexpensive.

Condenser Microphones:
Condenser microphones convert sound vibrations in the air into electrical signals through changes in the voltage of a charged diaphragm. Although their complex structure makes them more fragile and sensitive to humidity and high temperatures, they are compact and highly sensitive, capturing even the faintest sounds for delicate recordings. They require an external power source (phantom power), typically 48V, but 24V and 9V are also used. The term “phantom” means “ghost,” referring to the unseen power source.

For general field recording, condenser microphones are preferred for their superior sensitivity.

Advantages and Disadvantages of Dynamic Microphones

  • Advantages:
    Durable and resistant to humidity and high temperatures.
    Less susceptible to environmental noise.
    Relatively inexpensive.
  • Disadvantages:
    Low sensitivity, making them less suitable for high-quality recordings.

Dynamic microphones are ideal for capturing human voices and are commonly used in vocal mics and live streaming.

Advantages and Disadvantages of Condenser Microphones

  • Advantages of Condenser Microphones:
    High sensitivity and wide frequency response, allowing for high-quality recordings.
    Compact design.
  • Disadvantages of Condenser Microphones:
    Complex and fragile, sensitive to humidity and high temperatures.
    Relatively expensive.

Condenser microphones are suitable for delicate sound recordings. They are generally used in field recording for their superior sensitivity.

Chapter 2 – Microphone Directionality

Microphone directionality can be broadly categorized into three types: omnidirectional, unidirectional, and bidirectional. Unidirectional microphones capture sound from a specific direction and come in various types based on their pickup range. Field recording primarily uses omnidirectional and unidirectional microphones.

Omnidirectional

Omnidirectional microphones (omni mics) capture sound evenly from all directions around the microphone. These microphones are used to record the ambient environment rather than targeting a specific sound source.

  • Advantages:
    High flexibility in mic placement and natural sound capture from all directions.
  • Disadvantages:
    Can pick up background noise and are prone to feedback in certain recording environments.

Cardioid (Unidirectional)

Cardioid microphones are the most common type of directional microphones. The sensitivity pattern resembles a heart shape (cardioid), with high sensitivity at the front and decreasing sensitivity towards the sides. With an effective angle of about 130 degrees, cardioid mics can capture a broad range of sound.

  • Advantages:
    Less likely to pick up background noise, allowing for targeted sound recording.
    Good for isolating specific sounds.
  • Disadvantages:
    Requires precise positioning and is sensitive to proximity effect. These points apply to all directional microphones discussed below.

Supercardioid (Unidirectional)

Supercardioid microphones have a narrower pickup angle of about 115 degrees. They are ideal for capturing specific sounds while minimizing ambient noise.

Bidirectional

Bidirectional microphones, or figure-eight mics, have a sensitivity pattern shaped like a figure eight, capturing sound from the front and back while rejecting sound from the sides. They are suitable for recording conversations or interviews with two people facing each other.

Proximity Effect

As the sound source gets closer to the microphone, the bass frequencies become more pronounced. This phenomenon is known as the proximity effect, which can result in a boomy sound. The proximity effect is influenced by the directional pattern and distance of the sound source, with stronger effects observed in highly directional microphones. When using directional mics, it’s important to monitor the distance between the mic and the sound source to manage the proximity effect effectively.

Chapter 3 – Microphone Specifications

Each microphone has its own specifications listed.

  • Example: Specifications (Sennheiser MKH 8040)
    – Open Circuit Sensitivity: 20 mV/Pa (free field, no load, 1KHz)
    – Frequency response 30 – 50.000 Hz
    – Nominal Impedance: 25 Ω
    – Maximum SPL: 142 dB
    – Phantom Powering: 48V +/- 4 V
    – Audio Output: XLR
    – Dimensions: 19 x 41 mm (19 x 75 mm including XLR module)
    – Weight: 25 g (55 g including XLR module)

Sensitivity

Sensitivity indicates how easily a microphone can detect sound. It is typically expressed in dB (decibels). The higher the sensitivity of a microphone, the better it can pick up faint or distant sounds.

Generally, microphone sensitivity is expressed as the voltage level generated in response to a 94 dB sound pressure level (SPL) or a 1 Pascal (Pa) sound pressure. Higher sensitivity means that a larger electrical signal is produced for the same sound intensity, allowing the input level of the recorder to be lowered, which can also help reduce self-noise as described later.

Frequency Response

Frequency response refers to the range of frequencies (pitches) that a microphone can capture.

Frequency response is represented by a graph showing the range of frequencies and sensitivity. The horizontal axis represents frequency (Hz), and the vertical axis represents sensitivity (dB). (For directional microphones, comparisons with the angle to the sound source are also included.)

This graph visually represents the sensitivity of the Sennheiser MKH 8040 microphone to different frequencies.

Generally, the human audible range is said to be from 20 Hz to 20,000 Hz (20 kHz). A flat response within this range is preferred, as it indicates uniform sensitivity across all frequencies. Note that for specific applications, a special frequency response that emphasizes certain frequency ranges may be required.

Maximum Sound Pressure Level (Max SPL)

The Maximum Sound Pressure Level (Max SPL) indicates the highest sound pressure level that a microphone can handle. This value is usually measured in decibels (dB).

Max SPL is important for use in high-volume environments. Excessive sound pressure can damage the microphone or cause distortion. The higher the Max SPL value of a microphone, the more it can handle high-pressure sound environments.

Self-Noise | Equivalent Noise Level

Self-noise, or equivalent noise level, is the noise generated by the microphone itself in the absence of any sound source. Self-noise is measured in dB(A), with lower values indicating less self-noise.

Signal-to-Noise Ratio (S/N Ratio)

Additionally, the signal-to-noise ratio (S/N ratio) is another metric used. The S/N ratio represents the ratio of the signal (desired sound) to the noise. It indicates the output level when a reference signal is input, relative to the self-noise. The S/N ratio is measured in dB, with higher values indicating less noise interference relative to the signal. Detailed explanations and calculations of the S/N ratio can be found through further research.

Chapter 4 – Various Microphones

Typical microphones convert air vibrations into electrical signals. However, vibrations exist not only in air but also in water and solids, and there are microphones designed to capture these vibrations. Additionally, there are microphones with specialized recording methods.

Hydrophone

A hydrophone is a microphone designed to record underwater sounds. Like standard microphones, hydrophones use the principle of converting sound pressure into electrical signals, but they are specifically designed to capture sounds effectively in water.

Contact Microphone | Geophone

A contact microphone records the vibrations of objects. Unlike typical microphones that capture sound in the air, contact microphones directly detect the vibrations of objects, allowing them to record unique sounds and tones.

While contact microphones convert the vibrations of objects into sound, geophones are placed on the ground or underground to record Earth’s vibrations. They are mainly used in seismology and geotechnical engineering to measure internal earth vibrations and seismic waves. Geophones are also frequently used in field recording, with popular models like the Geofón by LOM.

Binaural Microphone

A binaural microphone is designed to capture sound as it is heard by the human ears. It is ideal for providing a sense of presence and immersion and is used to recreate 3D audio and spatial sound environments.

Various microphones are used for field recording. The optimal choice depends on specific usage scenarios and personal preferences, so it is best to consider what suits your needs. Below is a list of major manufacturers.

  • Sennheiser
    A German audio manufacturer known for high-quality audio products. They offer a wide range of products, from studio to field use.
  • Audio-Technica
    A Japanese manufacturer that provides high-performance microphones at affordable prices, widely used for studio recording and field recording.
  • Rode Microphones
    An Australian manufacturer offering condenser microphones, dynamic microphones, and portable recorders. Known for their excellent performance and affordable prices, they are popular for podcasting.
  • DPA Microphones
    A Danish manufacturer providing high-performance microphones that are highly regarded in the professional audio industry.
  • Lewitt Audio
    An Austrian microphone manufacturer offering high-quality and innovative audio products.
  • AKG Acoustics
    An Austrian manufacturer providing high-quality microphones for studio and live sound use.
  • Sony
    A Japanese manufacturer offering portable recorders and microphones suitable for field recording.
  • Zoom Corporation
    A Japanese manufacturer specializing in portable audio equipment, including recorders and audio interfaces.
  • TASCAM
    A professional audio equipment manufacturer offering portable recorders, audio interfaces, and microphones.

    There are also many small-scale manufacturers like LOM, Core Sound, micbooster, and microphone Madness.

Omnidirectional | Recommended Microphones

► LOM / basicUcho
The LOM basicUcho is a high-quality omnidirectional microphone known for its excellent cost performance. It features very low noise and high sensitivity, making it ideal for field recording. Designed to capture natural and expansive soundscapes, it is a reliable choice for recording environmental and ambient sounds.

► DPA CORE 4060
An ultra-compact omnidirectional lavalier microphone. Its small size makes it easy to handle, and it’s used for orchestral recordings among other applications. It captures natural and expansive sound in field recordings. Additionally, it is highly durable and resistant to humidity compared to typical condenser microphones.

Directional | Recommended Microphones

► SENNHEISER / MKE600
A supercardioid shotgun microphone. It offers excellent cost performance and is primarily designed for video and film production. It can capture clear and dynamic audio. Other options include the more expensive supercardioid MKH8060.

► Audio-Technica / BP4025
An X-Y stereo condenser microphone that provides rich, natural stereo recordings. It features a large 24.3mm diaphragm in a compact body and can record with a 120° stereo angle. Its design is also popular for its aesthetic appeal.

Handheld Recorders | Recommended Microphones

► TASCAM / Portacapture X8
A handheld recorder with large-diaphragm condenser microphones. It allows switching between A-B and True X-Y recording modes. It can be quickly taken out and used for recording anytime, anywhere. It also includes XLR connectors for external microphone connections.

Other | Recommended Microphones

► LOM / Geofón
A highly popular geophone designed for field recording. It captures very weak vibrations in various materials and soils. When used together with a regular microphone, it provides rich and layered sounds. Due to its high demand, it sells out quickly, so it’s recommended to monitor social media for updates.

Related article: LOM Geofón / Review

► AKG / C411 PP
The AKG C411 PP is a contact microphone designed for acoustic string instruments. It captures vibrations directly from surfaces, providing clear and natural audio while minimizing ambient noise. Its high sensitivity and clarity make it ideal for recording subtle environmental vibrations, and it requires phantom power.

► KORG / CM-300
The KORG CM-300 is a contact microphone designed for tuning and field recording applications. It clips onto instruments or surfaces to capture vibrations directly. While its sensitivity is moderate, it offers excellent usability and cost performance, making it a versatile and convenient choice for recording various types of vibration-based audio.

► Adphox / BME-200
A binaural microphone for spatial audio recording. Utilizing knowledge gained from hearing aid development, it is worn on the ears for easy binaural recording. The earphones and microphones are integrated, allowing monitoring while recording. A downside is its vulnerability to wind noise since the microphones are almost exposed.

BGD_SOUNDS (barbe_generative_diary SOUNDS)

barbe_generative_diary SOUNDS will start sharing and selling a variety of field recordings collected for use in my artwork “Sound Visualization” experiments. All sounds are royalty-free.

Link / BGD_SOUNDS on bandcamp