This page will have common and maybe some not so common terminology that is commonly found in the audio profession. Feel free to add new terms or add new or edit the definitions to make sure everything is correct. If you are siting a source, please be sure to give credit were it is due.

A - D

Bi-Directional (Microphone)

Figure 8 or bi-directional microphones receive sound from both the front and back of the element. Most ribbon microphones are of this pattern. [2]


Cardioid (Microphone)

The most common unidirectional microphone is a cardioid microphone, so named because the sensitivity pattern is heart-shaped (see cardioid). A hyper-cardioid is similar but with a tighter area of front sensitivity and a tiny lobe of rear sensitivity. A super-cardioid microphone is similar to a hyper-cardioid, except there is more front pickup and less rear pickup. These three patterns are commonly used as vocal or speech microphones, since they are good at rejecting sounds from other directions. A cardioid microphone is effectively a superposition of an omnidirectional and a figure-8 microphone; for sound waves coming from the back, the negative signal from the figure-8 cancels the positive signal from the omnidirectional element, whereas for sound waves coming from the front, the two add to each other. A hypercardioid microphone is similar, but with a slightly larger figure-8 contribution. [2]

Condenser (Microphone)
Also known as a capacitor microphone, the diaphragm acts as one plate of a capacitor, and the sound vibrations produce changes in the distance between the plates. The capacitor to charged to a specified voltage, as the sound pressure moves the second plate o fthe capacitor, the voltage of the capacitor varies slightly and this is passed on as the audio signal. [2]

Dynamic (Microphone)
Work via electromagnetic induction (a speaker in reverse). They are robust, relatively inexpensive and resistant to moisture, and for this reason they are widely used on-stage by singers.

E - H

• The hertz (symbol: Hz) is the International System of Units (SI) base unit of frequency. Its base unit is cycle/s or s-1 (also called inverse seconds, reciprocal seconds). In English, hertz is used as both singular and plural. As any SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 103 Hz), MHz (megahertz, 106 Hz), GHz (gigahertz, 109 Hz) and THz (terahertz, 1012 Hz).[1]
• One hertz simply means one cycle per second (typically that which is being counted is a complete cycle); 100 Hz means one hundred cycles per second, and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz.[1]
• is a traveling wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 16 Hz to 20,000 Hz; the average human can hear sounds between 20 Hz and 16,000 Hz. [1]

Hyper-cardioid (Microphone)

A hyper-cardioid is similar but with a tighter area of front sensitivity and a tiny lobe of rear sensitivity. [2]


I - L

M - Q

Sometimes referred to as a mike or mic, is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal.[2] A microphone is a device made to capture waves in air, water (hydrophone) or hard material and translate them into an electrical signal. The most common design uses a thin membrane which vibrates in response to sound pressure, this movement being subsequently translated into an electrical signal. Most microphones in use today for audio use electromagnetic generation (dynamic microphones), capacitance change (condenser microphones) or piezoelectric generation to produce the signal from mechanical vibration.[2] The Dynamic and Condenser microphones are the most common within sound systems.

Omnidirectional (Microphone)

An omnidirectional microphone's response is generally considered to be a perfect sphere in three dimensions. In the real world, this is not the case. As with directional microphones, the polar pattern for an "omnidirectional" microphone is a function of frequency. The body of the microphone is not infinitely small and, as a consequence, it tends to get in its own way with respect to sounds arriving from the rear, causing a slight flattening of the polar response. This flattening increases as the diameter of the microphone (assuming it's cylindrical) reaches the wavelength of the frequency in question. Therefore, the smallest diameter microphone will give the best omnidirectional characteristics at high frequencies. The wavelength of sound at 10 kHz is little over an inch (3.4 cm) so the smallest measuring microphones are often 1/4" (6 mm) in diameter, which practically eliminates directionality even up to the highest frequencies. Omnidirectional microphones, unlike cardioids, do not employ resonant cavities as delays, and so can be considered the "purest" microphones in terms of low coloration; they add very little to the original sound. Being pressure-sensitive they can also have a very flat low-frequency response down to 20 Hz or below. Pressure-sensitive microphones also respond much less to wind noise than directional (velocity sensitive) microphones.[2]

Phantom Power
Phantom power (labeled as +48 V on some audio equipment) is a method that sends a DC electrical voltage through microphone cables. It is best known as a common power source for condenser microphones, though many active DI boxes also use it. Phantom powering consists of direct current applied equally through the two signal lines of a balanced audio connector (in modern equipment, usually an XLR connector). The supply voltage is referenced to the ground pin of the connector (= pin 1 of an XLR), which normally is connected to the cable shield or a ground wire in the cable or both. With phantom power, the supply voltage is effectively invisible to balanced microphones that do not use it: e.g., most dynamic microphones. A balanced signal consists only of the differences in voltage between two signal lines; phantom powering places the same DC voltage on both signal lines of a balanced connection. Many sound boards have a switch for turning phantom power off or on; in most high-end equipment this can be done individually by channel, while on smaller desks all channels are either off or on at once. If it is desired to disconnect phantom power from one channel only, this can be done by using a 1:1 isolation transformer or blocking capacitors. Phantom powering can cause equipment malfunction or even damage if used with cables or adapters that connect one side of the input to ground, or if certain equipment other than microphones are connected to it.

Pick up Patterns
see Omnidirectional, Subcardioid, Cardioid, Supercardioid, Hypercardioid, Bi-directional, Shotgun. A microphone's directionality or polar pattern indicates how sensitive it is to sounds arriving at different angles about its central axis. The polar patterns represent the locus of points that produce the same signal level output in the microphone if a given sound pressure level is generated from that point. Since pressure gradient transducer microphones are directional, at distances of a few centimeters of the sound source results in a bass boost. This is known as the proximity effect [2]


R - U

Shotgun (Microphone)

Shotgun microphones are the most highly directional. They have small lobes of sensitivity to the left, right, and rear but are significantly more sensitive to the front. This results from placing the element inside a tube with slots cut along the side; wave-cancellation eliminates most of the off-axis noise. Shotgun microphones are commonly used on TV and film sets, and for field recording of wildlife. [2]

Solo bus
The only School bus worth being on, it's not the short bus, but it ain't long either…

Noise can be considered an unwanted sound

Sound Pressure Level (SPL)
Wikipedia defines Sound Pressure as the local pressure deviation from the ambient (average, or equilibrium) pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water. The SI unit for sound pressure is the pascal (symbol: Pa). Sound pressure level (SPL) is a logarithmic measure of the rms sound pressure of a sound relative to a reference value. It is measured in decibel (dB) 044fb8a52d5d73a7f323ff93d2ed03ee.png where pref is the reference sound pressure and prms is the rms sound pressure being measured [4]
SPL Weighting
There a number of wieghting curves that apply a "weighted average" to each SPL reading an adjust the curve based on how the ear hears. The most common weightings are A, B, C, D, and Flat. OSHA requires all noise readings to be taken with the A weight, and most all other countries have adopted this weight as well. "Originally, the A-frequency-weighting was only meant for quiet sounds in the region of 40 dB SPL, but is now mandated for all levels. C-frequency-weighting however is still used in the measurement of the peak value of a noise in some legislation, but B-frequency-weighting - a half way house between 'A' and 'C' has almost no practical use. D-frequency-weighting was designed for use in measuring aircraft noise" [5]

Subcardioid (Microphone)



Supercardioid (Microphone)

A super-cardioid microphone is similar to a hyper-cardioid, except there is more front pickup and less rear pickup. [2]


V - Z

Zero the console
Before starting the sound check it is good practice to ‘zero’ the console by setting all its controls to a sensible starting condition. Set all GAIN, EQ and PAN controls mid, FADER, AUX and MATRIX controls off, TALKBACK and OSC/NOISE levels off, and all switches up. Make sure the osc/noise generator is turned off.

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License