The better you understand your microphones and their distinct features, the more effectively you can use them. So, learning microphone terminology is not just a theoretical exercise but a practical step toward capturing better recordings. Here’s a quick reference list of commonly used microphone terms, their meanings, and how they can be applied to enhance your recording process.
Attenuation:
Attenuation is the process of reducing the amplitude of a signal. Many microphones feature built-in attenuation, also called a signal pad. A microphone attenuator lowers the signal amplitude within the microphone, allowing you to record loud sound sources without the risk of the mic overloading the preamp and causing distortion.
Balanced Signal:
A balanced signal is crucial in professional audio, especially with microphones. It generally involves sending two copies of the same signal down separate wires within a 3-conductor cable (the third cable is the ground). One of the signals is inverted at the sound source, flipping its phase by 180 degrees. This protects the original signal while canceling any unwanted noise.
Capacitor Microphone:
A lesser-used (but more accurate) name for what we commonly call condenser microphones. These microphones operate on the principle of capacitance (the ability of a material to store an electrical charge), hence the name.
Cardioid Microphone:
A directional microphone that mostly captures sound from the front and sides while mostly rejecting sound arriving at the rear of the microphone. Cardioid — which gets its name from the Greek word καρδιά (kardiá), or “heart” due to its similarly shaped pattern — microphones are best employed to reduce sound pickup from behind the microphone.
Condenser Microphone:
A microphone that operates based on the principle of capacitance. A condenser microphone’s capsule comprises a fixed backplate and a moveable diaphragm, both charged from a battery, phantom power, tube power supply, etc. When the movable diaphragm vibrates in response to sound pressure, the changing distance between the plates changes the circuit’s capacitance. This is then converted to an electrical signal amplified by a microphone preamplifier.
dB/Decibel:
dB is an abbreviation for Decibel or one-tenth of a Bel. The Bel is a relative unit of measurement developed by Bell Laboratories used to measure transmission loss or gain in telephone circuits.
While dB ratings measure the relative difference between two given values, there are also scales measured in actual values. These include dBu (decibels that measure voltage), decibels that measure acoustic sound pressure (dB SPL), and decibels that measure digital audio (dB FS).
An important spec for any microphone will be its maximum dB SPL rating: if a sound source exceeds the maximum dB SPL rating for the microphone, expect the mic to distort during recording.
Dynamic Microphone:
A type of microphone that operates on the principle of electromagnetism — an audio signal is created by a conductor moving in a magnetic field. There are two main dynamic microphones: moving-coil microphones and ribbon microphones. Unlike condenser microphones, dynamic microphones do not require a power source.
Dynamic Range:
Dynamic range quantifies the difference between the strongest and weakest levels in an audio signal. It is also used to describe the useful range of a microphone by quantifying the range between the noise floor (lowest possible signal level) and the maximum output level (highest possible signal level before distortion occurs).
Feedback:
Technically speaking, feedback is routing the output of an audio signal path back into the path’s input. In microphone terms, it’s the shrieking howl you hear from speakers when microphones are positioned incorrectly. Feedback occurs when a microphone picks up the amplified sound it is creating: to reduce the likelihood of feedback, aim microphones away from speakers and use close-miking techniques to reduce the amount of mic gain needed.
Figure-8 Microphone:
The figure-8 polar pattern describes a microphone that’s sensitive to sounds arriving at the front and back of the microphone while rejecting sounds from the sides. Ribbon microphones naturally have a figure-8 polar pattern due to the nature of a ribbon element, and some multi-pattern condenser microphones offer a figure-8 setting as well.
Gain:
Gain is the amplification applied to the level of an audio signal. Gain, measured in decibels (dB), directly increases the signal voltage, which raises the perceived loudness of the audio. In other words, if you connect a microphone to a preamplifier and turn up the gain, you are increasing both the voltage arriving at the preamp’s output and the overall loudness of the sound.
Gain Staging:
Gain staging is the process of ensuring that every link in an audio signal path is operating at the optimal signal-to-noise ratio. In other words, gain staging minimizes noise by ensuring that every device in the signal path adds as little gain as possible to maintain signal strength. Poor gain staging is the result of cranking up mic preamp gain instead of moving a microphone closer, adding gain with a console’s fader instead of the channel’s input gain control, and running power amplifiers or powered speakers at 100% power instead of a more reasonable 75-80%.
Highpass Filter:
A highpass filter is a circuit that removes low frequencies from an audio signal to capture “cleaner” recordings. Because it also passes midrange frequencies, it is often referred to as a low-cut filter. Many microphones feature a switchable highpass filter to help you optimize your sound right at the start of your signal chain.
Hypercardioid:
Hypercardioid microphones utilize a highly directional variation of the cardioid polar pattern. A hypercardioid microphone is less sensitive to sound arriving at the sides of the microphone than a cardioid microphone but slightly more sensitive to sounds arriving from the rear than a cardioid microphone. Think of it as halfway between the cardioid and figure-8 patterns.
Impedance:
Impedance measures a device’s opposition to the current flow, in this case, your mic preamp’s input impedance vs. your microphone’s output impedance. Measured in ohms (Ω), these ratings are crucial for understanding how the two devices interact. Check out our article, “How Impedance Can Change The Sound of Your Ribbon Microphone,” to learn more.
Microphone Preamplifier:
Mic preamplifiers (or preamps) are devices that increase the power of the electrical signal generated by a microphone. Mic preamplifiers (or preamps) are specifically designed for the low voltages that microphones produce, bringing them up to the industry-standard line level used by most audio equipment. Pictured above is one of our preamps, the AEA RPQ3.
Near-field, Far-field, and Mid-field Microphone:
AEA uses these terms to describe the optimal distances to place our mics from your sound source. Near-field microphones are ideal for close-miking techniques. Far-field mics are used at a distance to most accurately capture the sound of the recording space. Mid-field microphones blend the strengths of the other two, capturing up-close clarity and room ambiance simultaneously. Pictured above are the N8 (Far-field), N22 (Near-field), and N13 (Mid-field).
Omnidirectional Microphone:
Omnidirectional microphones are equally sensitive to sound arriving from all directions. Their natural sonic character is ideal for applications where you want to capture an entire space or a wide sound source (such as a choir) with an in-the-room character.
Resistant to proximity effect, you can place omnidirectional mics wherever they give you the most balanced sound with the desired amount of room ambiance.
Phantom Power:
Phantom power supplies 48 volts of power to an active microphone via the same cable carrying the audio signal. Audio devices such as microphone preamplifiers, mixing boards, and recording interfaces often provide this feature, which is commonly labeled 48v or P48.
Polar Pattern:
A microphone’s polar pattern dictates its sensitivity to sound pressure from different directions. As a microphone’s sensitivity is frequency-dependent, its polar pattern will generally show slightly different plots for different frequencies.
Proximity Effect:
Proximity effect is the increased sensitivity to bass frequencies a microphone exhibits as you move it closer to a sound source. Audio engineers and broadcasters have long used it to create a larger sound with added warmth.
Highpass/Lowpass filtering:
These filters remove unwanted high and low frequencies from your signal. They get their name for the frequencies they allow to “pass” through unaffected.
High Cut/Low Cut filtering:
Identical to Highpass/Lowpass filters, cuts are a different, simplified way to describe how they affect your signal.
Frequency Roll-off:
Roll-off describes the natural-sounding way filters can remove unwanted frequencies from your signal. The frequencies decrease gradually for a more musical character.
Spaced Pair Miking:
Also referred to as A-B miking, a spaced pair is a stereo miking configuration with two microphones spaced around 3-10 feet apart and at the same height. The distance between the mics creates differences in the phase (time) and amplitude (signal strength) domains, resulting in a very wide stereo image compared to XY stereo miking.
Supercardioid Microphone:
More directional than a cardioid microphone but less directional than a hypercardioid microphone, the supercardioid polar pattern is less sensitive to sounds from the sides and rear than sounds at the front of the mic. A great example is the AEA KU5A pictured above.
Transducer:
Any device that transforms one type of energy into another is a transducer. A microphone is a transducer that transforms acoustic pressure into an electrical voltage, while a loudspeaker is a transducer that does the opposite.
XLR:
ITT/Cannon Electric developed a multi-pin connector for connecting microphones to other audio devices. Cables with these 3-pin XLR connections, commonly called mic cables, combine three wires — positive, negative, and ground — allowing clean audio transfer over long runs. The XLR connection is also locked for added reliability.
XY Miking:
XY miking is a stereo miking configuration used in such techniques as Blumlein and Mid/Side. It involves two directional microphones with capsules aligned and angled 90 degrees from each other. When mixed down to mono, the resulting stereo image will have fewer phase issues than A-B miking.