Because of their sensitivity and quality, condenser mics are among the most widely used mic options for studio recording applications.
Condenser microphones typically have a lower input responsivity than their dynamic counterparts but offer a broad frequency response range. In other words, they’ll take in more incoming signals more quickly.
Accordingly, the majority of condenser mics (with a few outliers) are best suited for quieter settings, such as those found in studios.
This article will discuss condenser microphones (see also ‘What Does Mic Up Mean?‘), how they work and what they are used for.
How Do Condenser Microphones Work?
In essence, condenser microphones are very sophisticated capacitors. A capacitor is an electronic part intended to momentarily store the energy inside an electric field (for those of us without an electrical engineering degree).
In order for capacitors to function, two plates must be placed close to one another. The capacitance, or capacity to store electric charges, increases with their proximity.
One of these plates serves as the diaphragm of a condenser microphone and is constructed of an extremely light, typically very thin material.
When sound waves hit the diaphragm, the spacing between the two plates changes, changing the capacitance as a result.
An electrical depiction of the acoustic waves from the input signal is produced by the resultant variation in capacitance.
The output of a DC-polarized compartment must be transformed by active circuitry from a very high impedance to a practical low impedance; this circuitry is frequently powered by +48V phantom power.
Other techniques include batteries and dedicated power supply, which are typically used with tube condensers. Electret condensers frequently use batteries.
They are known as “capacitor microphones” in the UK, and for good cause. A capacitor is two essential metal plates placed close together, as you might recall from physics class. The capacitance increases with proximity.
The design of a condenser compartment is similar. It is made up of a thin barrier that is situated adjacent to a sturdy metal plate.
The membrane, or diaphragm as it is frequently called, must at least have a surface that is electrically conductive. Gold-sputtered mylar is the most popular material, but some (mainly older models) use a very thin metal foil.
However, the capsule signal is far too “fragile” to be linked to other equipment. The output voltage of the condenser capsule is actually rather high, but essentially no current is produced because there is so little energy stored in this tiny capacitor.
It needs a circuit known as a “impedance converter,” which acts as a buffer between the compartment and the outside environment. By allowing for larger signal current, the impedance converter strengthens the signal.
Therefore, condenser microphones need external power. In the past, this would have been a hassle, but today, nearly every microphone input has P48 phantom power.
Powering A Condenser Microphone
The internal circuitry of condenser mics requires external power. Early examples used tube electronics and were controlled by an outside PSU unit the size of a brick.
This proved problematic in a variety of ways, especially when multiple microphones were in use at once and each kind needed its own PSU box and unique multi pin cable.
Neumann developed a standardized method to power condenser mics directly from mixing desks without the need for separate PSU boxes and multi pin connections when transistor technologies took hold in the late 1960s.
Dynamic mics that do not rely on external power are unaffected by P48 phantom power, which operates with 48 volts and is provided via the standard 3-pin microphone connection.
P48 phantom power quickly became the norm worldwide because of how convenient it was.
Lately, tube technology has gained popularity once more as a “vintage” sound substitute. Like their predecessors, modern tube condenser mics need an external power source because tubes utilize more power than phantom power can supply.
Variations Of Condenser Microphones
Condenser microphones are renowned for their exceptional sound quality, particularly when picking up fine details, thanks to their diaphragm.
In contrast to the bulky moving coil linked to a dynamic microphone, the modest weight of a condenser microphone’s diaphragm enables it to vibrate with the acoustic energy of an input signal more accurately.
Condenser mics are therefore acknowledged to have greater sound quality, the largest resonant frequency, and the highest capability to faithfully reproduce transients, regardless of size.
It’s typical to hear the terms “small diaphragm,” “big diaphragm,” and “electret” when looking for condenser microphones.
The electronic signal that we capture in a condenser mic is produced by the motion of a flexible diaphragm, thus it is obvious that the size of a diaphragm impacts how it reacts to sound waves.
The electret condenser is a popular and reasonably priced variant.
As was previously established, a condenser capsule requires a voltage charge in order to detect the capacitance change brought on by the diaphragm moving in time with the sound waves.
This polarization voltage needs to be quite high in order for the mic to operate at its highest sensitivity.
Larger diaphragm mics are typically used to record pianos, acoustic guitars, vocal ensembles, and groups of instruments.
They work well for miking a “room” in order to better capture the atmosphere. Usually, only instruments are recorded with small-diaphragm microphones.
Remember that there is no law that says you can only use a big diaphragm mic for drum overheads and a smaller diaphragm mic for voices.
Instead than picking up sound from the end of the microphone, numerous large-diaphragm microphones are made to capture sound from one or both sides.
Most pencil-shaped small-diaphragm microphones capture sound from the end rather than the side. As a result, they are “end-address” rather than “side address.”
Understanding where your microphone’s focal point is placed will help you see its polar pattern more clearly and direct it more precisely towards the audio source.
When you only use one microphone on a sound source, it doesn’t matter if two microphones of the same type may respond differently.
However, if both microphones react identically while capturing through stereo, you will get a far more coherent and consistent sound.
Hopefully, this article has helped you to understand a little more about condenser microphones. They are very sophisticated capacitors which provide useful functions and better sound quality in a variety of roles.