What Is A Condenser Microphone Used For?

Condenser microphones are one of the most popular mic choices for studio recording applications because of their sensitivity and fidelity. Simply put, condenser microphones are more sensitive than their dynamic siblings, and due to their design, are better at picking up more detail in a recording, with lower self-noise and better accuracy across a wider frequency spectrum. This increased sensitivity comes with some disadvantages in certain recording scenarios — condensers will generally pick up unwanted background sounds more readily, so aren't as suited for use in spaces with lots of reflective surfaces or in particularly noisy environments. Also, condenser microphones are typically less rugged than dynamic microphones and may not be suited to applications like live performance, where they may be dropped or knocked around.

How a Condenser Microphone Works

Condenser mics get their name from the "capacitor" inside that converts acoustic energy into an electrical signal ("condenser" is an old term for "capacitor"). The British call them "capacitor microphones" — and for a reason, too. A condenser capsule consists of a thin membrane in close proximity to a solid metal plate. The membrane, or diaphragm, must be electrically conductive, at least on its surface. The most common material is gold-sputtered mylar, but some (mostly older) models employ an extremely thin metal foil.

When sound waves hit the diaphragm, it moves back and forth relative to the solid backplate. In other words, the distance between the two capacitor plates changes. As a result, the capacitance changes to the rhythm of the sound waves, converting sound into an electrical signal. The resulting signal doesn't have a strong enough current to be output as is, which is why condenser microphones have an on-board preamp to boost it. This preamp — and in some designs, the charged metal plate as well — requires external power to function. In most modern, transistor-based microphones, this is supplied by 48v phantom power sent via the XLR cable used to connect the mic to a mixer or audio interface. Without this external power, condenser microphones cannot operate.

Types of Condenser Microphones

Large-Diaphragm Condenser Microphone

Large-diaphragm condenser microphones utilise a larger membrane in their capsule. A condenser microphone with a diaphragm of 1 inch (25.4mm) or greater is considered a large diaphragm as a rule of thumb. One of the biggest technical advantages of this design is that its larger diaphragm can generate a higher signal voltage, which in turn results in the microphone producing less of its own noise (self-noise). Large-diaphragm condensers typically have a less consistent pickup pattern than small-diaphragm counterparts. While this may not be ideal if you're aiming for a perfectly uncoloured recording, it is what accounts for the 'lush' and 'warm' character often attributed to these microphones and is what makes them ideal for recording vocals, and in a range of other applications. In general, large diaphragm microphones are used to record vocals, ensembles, acoustic guitars, and pianos. They are also great for miking a "room" to better pick up the ambience.

Small-Diaphragm Condenser Microphone

Small-diaphragm condenser microphones typically produce a flatter and less 'coloured' signal than their large-diaphragm counterparts, meaning they give you a very accurate audio image. They typically have an extended low- and high-frequency response, and a consistent pickup pattern that helps capture sounds as 'naturally' (or 'neutrally') as possible. It's generally accepted that "small" refers to anything with a diameter of half an inch (12.7mm) or less. This smaller membrane also results in a superior transient response ideal for recording sound sources with a fast attack, like piano, drums and stringed instruments. Small diaphragm microphones are generally used exclusively for instruments (close-miking an acoustic instrument, overheads for drums, horn sections, etc.). While almost all large-diaphragm microphones are side-address, small-diaphragm mics can be either side- or end-address.

Tube Condenser Microphones

Tube condenser microphones utilise a vacuum tube (also known as a valve) in their preamplifier circuit rather than transistors. This style of microphone was the first to be developed amongst the condensers. Among the qualities of a tube microphone is that they tend to add pleasant harmonics to a sound source, as well as subtle saturation and compression. While this character can be desirable, tube mics also tend to come with a higher self-noise level and require a separate power supply to operate — 48v phantom power from your audio interface won't cut it.

Shotgun Microphones

Shotgun microphones are a type of condenser mic distinguished by their long, tubular design. The purpose of a shotgun microphone is generally to record audio from a distance while maintaining focus and clarity. Sound waves enter through the front of the microphone, as well as from the side ('off-axis') via perforations. This disrupts (or 'interferes' with) how the sound waves reach the capsule, resulting in these 'off-axis' sounds being filtered out through a process known as phase cancellation. Shotgun microphones are used on top of a camera, on a boompole, or in studio applications where you need to isolate a sound source, such as foley work.

USB Condenser Microphones

The major point of difference for a USB microphone is the way the signal is output. Rather than an analog XLR connection, USB mics feature a USB output and on-board A/D (analog-to-digital) converters for turning the electrical current produced by the capsule into a digital signal that can be sent directly to a computer or other digital recording device. This makes them ideal if you're after a simple, all-in-one solution for recording audio into your computer as there is no need for any extra equipment, such as an audio interface or mixer, and you generally just need a single cable to get up and recording. Most USB mics even feature a headphone output for directly monitoring your recording or for playback from your device.

What Is a Condenser Microphone Used For

Condenser microphones are versatile tools that can be utilized in various recording scenarios. Their sensitivity and ability to capture a wide frequency range make them suitable for many applications. Most commonly, condenser microphones are used in the studio where their superior frequency and transient response, as well as their lower self-noise, are great for capturing clean, high-fidelity recordings that are true to the sound source.

• Vocals and voiceovers: Whether you're recording lead vocals, backing vocals, or voiceovers, condenser microphones provide the clarity and detail needed to capture the human voice in all its nuances.
• Drum kits: Condenser mics are often used as overhead mics for drum kits, capturing the cymbals and overall ambiance of the drum set. They can also be used for specific drum pieces like the snare or toms.
• Acoustic instruments: The sensitivity of condenser microphones makes them ideal for recording acoustic instruments, such as guitars, where capturing the natural resonance and overtones is essential.
• Field recording: Small diaphragm condenser mics are commonly used in field recording to capture ambient sounds, nature sounds, or on-location audio for film and video production.
• Podcasting and broadcasting: USB condenser microphones offer a convenient solution for podcasters and broadcasters, providing plug-and-play functionality without the need for additional equipment.
• Live performances: While not as common as dynamic microphones for live sound, condenser mics are sometimes used for live performances, especially when a more detailed sound capture is desired, such as with choirs or orchestras.
• Professional studio environments: Large diaphragm condenser mics are favored for their ability to capture a wide frequency response and subtle sonic details, making them a go-to choice for many producers and sound engineers.

Advantages of a Condenser Microphone vs a Dynamic

1. They produce very accurate audio with a wide frequency response and low self-noise. Condenser microphones utilise a super-thin membrane as their diaphragm, which has a lower mass and is more responsive to sound pressure. As a result, they produce a more accurate representation of the sound source with lower self-noise, a wider frequency response, and better transient response (meaning fast-attack sounds like percussive hits and string plucks will be picked up more accurately).
2. They require less gain to achieve a good recording level. Because condenser microphones feature an internal preamplifier circuit, they have a stronger output than their dynamic counterparts, meaning they require less gain from an audio interface or mixer to achieve a good recording level.
3. They are more sensitive, making them ideal for recording at a distance. Condenser microphones are more forgiving than dynamic alternatives when it comes to the proximity between the mic and your sound source. A condenser microphone will be able to pick up the sound more consistently and from further away than a dynamic mic, in turn resulting in a more balanced recording.

When to Choose Dynamic Over Condenser Microphones

While condenser microphones are useful in a wide range of situations, there are some common use cases where dynamic microphones are a better choice. If your recording environment lacks soundproofing or if there are a lot of competing sounds present (for example, in a live performance scenario), the higher sensitivity of condenser microphones means they may pick up these unwanted sounds. In these scenarios, a dynamic may be more suitable.

If you're planning on handling the microphone or moving around during recording, a dynamic will often be better as they are less prone to picking up handling noise — though in some cases this is accounted for with shock mounting, such as with shotgun microphones. If the sound source you're recording has the possibility of getting unexpectedly loud, then condenser microphones may not be ideal as they can distort at high volumes due to their sensitive nature and also may overload the input of your recording device due to their higher output level. They are hugely versatile and typically what you'd call a 'workhorse' microphone as they can be used in a wide variety of recording applications, from recording vocals and spoken word to acoustic and electric guitar, drums, piano and more.