AC power - The connection to the wall for 110V.
Amplifier - A device used to make an audio signal greater. It does not do anything more or less, although a mixer may be in the same box and the box is then called the amplifier.
Attenuate - To reduce in level.
Attenuator - A device used to reduce the level of a signal. This can be a resistor network or a control on a piece of equipment.
Audio chain - A series of equipment, linked together in such a way that the sound signal has to go through each piece of equipment in order.
Audio snake - Another term for snake or microphone snake. Used to connect several microphones on the platform to the mixer.
Audio spectrum analyzer - A device to see the signal strength of all the frequencies of audio.
Aural exciter - A device that is used to put certain harmonics onto an audio signal to make up for losses due to recording.
Auxiliary - A secondary signal, a line level signal or an input or output from equipment that is a higher level than mic level signal but lower level than speaker level signal.
Auxiliary input - The input to equipment that uses line level audio.
Auxiliary level - A line level signal.
Auxiliary output - A line level output from a piece of equipment.
Ax Axe - Slang for guitar.
Balanced microphone - A term for the number of wires inside the microphone cable. To be balanced, there are two wires that carry the audio signal in opposite directions at the same time. The shield of the cable is used only to keep unwanted signals out. Low impedance is usually associated with this.
Bass - A speaker that is used for low frequencies. Also a type of guitar and a type of fish.
Bass woofer - A speaker that is used for only the very low frequencies.
Bi-amp - A dual amplifier system that is used to operate the bass and treble speakers in a system after the audio signals have been split by a crossover network. This crossover network may be in the same box as the amplifier.
Buffer amplifier - An amplifier used to isolate a signal so that other signals on its output will not affect the input. It is also used so that a lower power signal may power several destinations.
Bus - A connection between several parts of a mixer. Example, several inputs can be connected to the auxiliary output bus of a mixer.
Buzz - An unwanted sound that is caused by dimmers or other electronic devices and is heard in the sound system.
Cans - Something worn over the ears to allow sound to be heard without interference from other sounds in the room and without sending out interfering sound. Also known as headphones.
Cardioid microphone - A directional microphone. Cardioid comes from the Greek word for heart and the pickup pattern is somewhat heart shaped. The back of the microphone has no pickup at all, and it is somewhat directional towards the front.
Channel - One input to an audio mixer. It can be one microphone or one side of a tape machine or one instrument. There is one volume control or fader for the channel. There may or may not be other adjustments for the channel. It is also the left or right signals in stereo. It can also be one audio signal in a group of audio signals.
Channel adjustment - The volume or level control for a particular channel of a mixer. Can be either a knob or slide control.
Channel fader - The volume or level control for a particular channel of a mixer. Usually a slide control.
Clip - The phenomena where an audio signal has its positive or negative excursions cut off because it has exceeded the ability of the electronics to pass it.
Clip LED - A light on the mixer or other piece of equipment that indicates that the audio signal is past the limits of the electronics. It indicates that there is distortion occurring.
Clock position - The position of a knob or dial where the pointer is pointing to an equivalent position on a standard 12 hour analog clock.
Compression - The effect where the average audio in a system is not allowed to be higher than a certain level. This can be used to make all the sound the same volume.
Compressor - This equipment starts to decrease the gain of an amplifier when the audio signal exceeds a certain level.
Condenser microphone - Condenser is another word for capacitor. This microphone uses a charged capacitor to pick up the sound from the air and convert it into an electrical signal.
Crossover network - A device that separates the high frequency audio signals from the low frequency audio signals so that the signals may go to different speakers.
Crosstalk - A phenomena where the audio from one channel bleeds into another causing an undesirable effect. This is present in all electronics to some extent or another and will be rated in dB when there is a rating on the equipment. It also is the unwanted signal that gets passed between audio lines that are too close together.
Crystal microphone - A microphone that uses a crystal to generate the electrical signal that is amplified as audio.
dB - An abbreviation for Decibel. Balanced microphones are usually measured at -50dB to -60dB. Auxiliary or line levels are usually -10dB to +4dB.
DC power - Low voltage power that is used to run equipment.
Decibel - One tenth part of a Bell. Used to indicate audio levels. Uses a logarithmic scale where 10dB is a difference of 10 times the power. 10 more dB (20dB) makes a difference of 100 times the power, etc. Designed to match the hearing level differences in the human ear.
Delay - The length of time that it takes sound to travel a certain distance through the air.
Delay line - A device that delays the audio signal that goes through it a fixed amount of time. Usually uses digital conversions.
Destination - Where an audio signal is going. Usually it is an input to some piece of equipment.
Directional microphone - A microphone that picks up sound better from one direction than from another. Examples of directional microphones are cardioid, super cardioid, hyper cardioid, bi-directional, stereo.
Distortion - An unwanted changing of the audio signal that is caused by a number of factors. One thing that causes distortion is the clipping of the positive or negative excursions of the signal because the electronics cannot handle that strong of a signal. Guitar amplifiers sometimes have boxes that produce this kind of distortion deliberately.
Duct tape - Used when nothing else will work.
Dynamic microphone - This microphone uses a magnet and a coil of wire to produce an electrical signal.
Dynamic range - The amount that a voice or other sound source varies in level. An example would be a person whispering one moment and shouting the next. This would show a lot of dynamic range.
Echo chamber - A room with hard, sound reflective walls. It has a speaker to put sound into the room and a microphone to pick up the sound. This kind of room one is one method of putting reverberation onto the audio signal.
Echo unit - A piece of equipment that produces an echo. Similar to, but not the same as a reverb unit.
Eff. - An abbreviation for Effects.
Effects - A modifying of the audio signal. Reverb is an effect, so is compression, limiting, aural exciting, etc.
Effects send - A knob on the mixer that sends the signal to the effects that are being used.
Effects return - The place in a mixer that the audio from the effects equipment is returned to. There is usually a control that adjusts the level of this audio signal.
Efx. - An abbreviation for Effects.
Electret - A piece of plastic that has a static charge of electricity built into it. It is used inside of a condenser microphone so that battery power doesn't have to be used to charge the condenser, or capacitor.
EQ - Short for equalization.
Equalization - Adjusting the frequency response so that the levels of all frequencies are equal or the same. Bass and treble controls are equalization controls.
Equalizer - A device that makes different pitches of sound louder or quieter and can be used for equalization. It is basically a glorified bass and treble control.
Feedback - That annoying tone or set of tones that occur because the sound of the speaker is getting into the microphone. It can be caused by the direct sound from the speaker getting into the microphone but is more often caused by the room reverberations that are excited by the speaker getting into the microphone.
Flange - A piece of special effects equipment that produces a fuller sound to music by a short delay and modulation of the frequency. The delay is shorter than is used in stereo chorus.
Flutter echo - The concentration of sound in one spot in a room by concave reflectors like rounded walls or ceilings or the repeat of sound echo from systematic bouncing of the sound back and forth in a room.
Foot switch - A switch that may turn on and off something or trigger something using the foot to actuate it.
Frequency - The "pitch" of sound. All sounds that we hear are made from different frequencies. The frequency of A above middle C is 440 Hz (cycles per second).
Frequency response - How the different frequencies are reproduced in a system. The human ear, at its best, has a frequency response of about 20 Hz to about 20 KHz (20,000 cycles per second). Good electronic audio equipment may have a response of 20 Hz to 20 KHz plus or minus 1 dB.
Front panel controls - These are controls that are meant to be adjusted on a day to day basis.
Gain - The amount of level boost in an amplifier or audio system.
Gain amplifier - An amplifier whose purpose is to make the audio signal stronger.
Gain before feedback - The maximum that a microphone may be turned up before there is feedback in the room.
Gain control - The knob or slider that adjusts the level of increase for the system or part of the system. This is how volume is adjusted. Another term for this is level control.
Graphic equalizer - An expanded name for an equalizer. It usually implies that there are a larger number of controls. Graphic in the name means that the sound can be made to compliment the sound of the room as if the frequency response were laid out on a graph.
Ground - The zero voltage reference point. The part of the system that carries away unwanted signals. The part that protects against electric shock.
Ground loop - An unwanted signal that is on the ground of an electronic system that will produce audio where it is not wanted. Usually 60 Hz hum, power supply hum, or light dimmer buzz.
Group - On larger mixers a group is several channels of audio that are on one bus or controlled by a group master.
Group master - The master control that is a single level control for the group of channels that are assigned to that bus.
Headphones - Something worn over the ears to allow sound to be heard without interference from other sounds in the room and without sending out interfering sound. Also known as "cans".
Headroom - The extra space above one's head so that there will not be a problem walking around. The extra signal room in an electronic circuit to prevent slight over levels from being clipped and distorted.
High equalization - Another term for treble control. Usually adjusts the higher frequencies.
High impedance - A method of sending the signal from one piece of electronic equipment to another where the voltage is relatively high and the current is relatively low. There are less electronics needed in the equipment but it is more susceptible to outside interference noise like a light dimmer or ground loops. It is usually not used in a broadcast station anywhere for audio but often used in churches between equipment. Most churches do not use it for microphones because of the extra noise it picks up.
High impedance microphone - A microphone that uses high impedance signals to go to the amplifier.
High level - Referring to an audio signal that has much greater strength than a microphone. Usually it is the line level signals that go from one piece of equipment to another but also may be referring to speaker level signals.
High Z - High impedance.
Horn - A speaker that is used for high frequencies. It can handle relatively high power and has a very specific spread or dispersion to the sound.
House Mix - Adjustment of the fader levels affecting balance of sound from the main speakers (audience speakers).
Hyper cardioid microphone - This microphone is more directional than the cardioid microphone. It is more sensitive to sound in front of the microphone, and less sensitive to sounds that come from the sides and back of the microphone.
Hum - The unwanted low frequency noise that sometimes is noticed in an audio signal and is usually caused by signals from the power line getting into the system.
Hz - Another term for cycles per second.
Impedance - A term for the different voltage/current ratios that are used in audio. Terms for impedance are things like 8 ohms, 600 ohms, 10 K ohms, low impedance and high impedance.
Input - The place that the audio signal goes into a piece of equipment. Examples are where the microphone signal or tape machine signal goes into the mixer.
Input gain - A volume control on the input to a mixer that will control the amount of audio signal that goes into the electronics. It is used so that the signal will not be so weak that you can hear the electronic noise in the circuitry and not so strong that the circuitry will clip and distort the audio signal.
Input trim - The same as input gain.
Insert - A port or connection on an audio mixer that gives the ability to take an audio signal from one channel of the mixer, process it in some way, and feed the signal back into the same channel of the mixer. This new signal may then be mixed in with other signals in the mixer.
Instrument - A device used on stage to create musical sounds. Instruments are such things as the electronic organ, keyboard, piano, guitar, trumpet, tambourine, flute, drums, bass, etc.
Instrument microphone - A microphone with a flat frequency response that is used with instruments because of its flat frequency response. Because it is not usually less than a foot from the instrument, the proximity effect is not noticed.
Isolation amplifier - Used so that an audio signal can go one way through an amplifier but an unwanted audio signal cannot go backwards through the same amplifier.
Isolation transformer - A device that is used so that audio may be passed while unwanted ground loop signals are not.
KHz - A term for thousands of cycles per second. "K" stands for kilo or thousand. "Hz" stands for the cycles per second.
L pad - A control that is used to set the sound level on a loudspeaker. This can only reduce the sound coming out of the speaker.
LED - Light Emitting Diode. These are common panel lights on the front of mixers or other equipment.
LED bar - usually a line of LEDs that are used to make up a lighted VU meter.
LED array - Usually a line of LED's that are used to make up a lighted VU meter.
Level - A term for the amount of audio that is present.
Level control - A means of adjusting the amount of audio. Other terms are volume or gain controls.
Limit LED - A light on the mixer that tells the operator that the limits on the electronics have been reached and that therefore there may be some distortion.
Limiter - A device that will not allow sound to be any higher than a certain level, but does nothing to the sound as long as that level is not reached.
Limiting - Where an audio signal is not allowed to have excursions beyond a certain point, either positive or negative. This can be done either deliberately, as with a limiter, or accidentally where the signal is clipped and therefore distorts.
Line cord - A cord that connects the electronic equipment to the 110V power.
Line level - Audio that is used to go from one piece of equipment to another. Depending on the system this can be anything from -10 dB to +4 dB in a high impedance system. It is usually 0dBm in a balanced system. Another term is auxiliary level.
Low equalization - another term for bass control. Usually adjusts the lower frequencies of audio.
Low impedance - A method of sending the signal from one piece of electronic equipment to another where the voltage is relatively low and the current is relatively high. This is the system that is commonly used in broadcast stations for everything and most churches for the microphones.
Low impedance amplifier - An amplifier that is used in a mixer to increase the voltage used with a low impedance microphone so that it will have the same voltage as high impedance microphones or line level signals.
Low impedance microphone - A microphone that has a low impedance output.
Low level - Referring to an audio signal that has a much lower strength than line level. Usually it is the microphone level signals, although it can be referring to line level signals if they are being compared to speaker level.
Low Z - Low impedance.
Main controls - These are often called the master controls.
Master - The main signal in a device. It is what the final signal comes down to.
Master adjust - Another term for the final adjuster in a mixer.
Master fader - Another term for the final adjuster in a mixer.
Master level - The amount of signal that is on the master output of a mixer.
Master control - The master fader or adjuster on a piece of equipment or the room where the main controls are located.
Master tape - The tape that is the final version of what is recorded. All tapes made from this tape are dubs, or duplicates.
Master recorder - The tape recorder that is used to make the master tapes. It is sometimes used with a slave player.
Matching transformer - An impedance matching transformer that is used to match a low impedance source to a high impedance destination or vice versa.
Microphone - A device that converts power in the form of sound waves into electrical power. This can be directional or nondirectional, flat frequency response or contoured, fixed or mobile, condenser or dynamic or one of many other types, wired or wireless, high or low impedance, with or without preamp, etc.
Microphone level - A term for the amount of signal that comes out of a microphone. Usually very low. Also it is a term for the adjuster for a particular channel on a microphone mixer.
Microphone transformer - A matching transformer that is used to match the impedance of a microphone to the impedance of the amplifier to which it is connected. It may be low to high impedance or high to low.
Mid equalization - Adjusts the middle range of frequencies.
Mixer - The piece of equipment that takes the different sources of audio and blends them together to get a final sound from all sources of sound at once.
Mixing - The act of mixing together all of the different sources of audio.
Monitor - To listen to the sound. This may be a musician on the platform, the sound man or anyone else listening. It may also be the loudspeaker that is used by the musician on the platform to listen to the sound.
Monitor send - An output from the mixer board that sends audio to the monitor amplifier. There is usually a level control associated with this.
Monitor speaker - A speaker that is used by those on the platform to hear what they are really doing and what others are doing. This is where there is either too much ambient sound, or there is too much distance from the source of the sound to hear properly.
Mute - A term for the stopping of sound from the speakers. It is like a mute person that cannot talk.
Mute switch - The switch on a mixer or other device that when engaged cuts the output.
Noise, electrical - Random signal that is present in all electronic equipment to some extent or another.
Noise gate - A device that entirely turns off the audio when the audio goes below a pre-set level. That way random noise will not be heard on the output because the only time the system is turned on is when there is wanted sound that drowns out the noise.
Omni-directional microphone - This kind of microphone picks up sound from all directions equally well.
Output - The place that the audio signal goes out of a piece of equipment. Examples would be the speaker output from an amplifier or the tape output from a mixer.
Pan - A knob on stereo mixers that routes the audio signal from a particular input channel to either the left or right stereo channels or a mixture of both.
Patch - A cord that is used with a patch panel.
Patch panel - A group of jacks in a panel that can have cords plugged into them so that signals can conveniently be routed and changed.
Phantom power supply - The power supply that can be used with a condenser microphone instead of having to use batteries in the microphone or the microphone cord. This will either be a part of the mixer/amplifier or an external box that is added to the microphone line and plugged in.
Phone plug - Usually 1/4 inch. Used with tip and sleeve or tip, ring and sleeve - for carrying electronic signals. The sleeve is used for ground and the tip and ring carry the signals.
Phono plug - A common plug used to connect audio between different pieces of equipment. Also called an RCA plug.
Play - The action of a tape recorder to reproduce the audio that has been recorded on a tape. The button that is used to cause a tape recorder to play. What children do. The act of causing a tape recorder to reproduce the audio that has been recorded.
Polarity - The wiring of a microphone or speaker to make sure that the movement of air will be in the same direction as the electrical signal. Also of concern between equipment in a balanced system.
Post equalizer - A signal that is taken from the mixer or inserted into the mixer after the channel equalizer but before any other part of the mixer.
Post fader - A signal that is taken from the mixer or inserted into the mixer after the channel fader but before any other part of the mixer.
Pre equalizer - A signal that is taken from the mixer or inserted into the mixer before the channel equalizer but after all the circuitry that is before the equalizer.
Pre fader - A signal that is taken from the mixer or inserted into the mixer before the channel fader but after all the circuitry that is before the fader.
Power amplifier - An amplifier that takes line level audio signals and make them strong enough to power a speaker.
Power supply - The part of a piece of equipment that provides the electricity for other parts.
Preamp - An amplifier that is used before the main amplifier in a system. Usually this is an amplifier that takes microphone level signals and brings them up to line levels.
Processor - A piece of equipment that changes the audio in some way. Example: Reverb, Compressor, Limiter, Delay, etc.
Proximity effect - The phenomena where the sound picked up by a directional microphone has a bass boost that is caused when the source of sound is within a few inches. Vocal mics have a bass "roll off" to compensate for this.
RCA plug - a common plug used to connect audio between different pieces of electronic equipment. (See previous page.)
Record - The act of storing an audio signal for later playback. The input to a tape recorder.
Resonance - The systematic bouncing of sound around a room where certain sounds are reinforced and others are canceled. This reinforcement produces standing waves and flutter echoes.
Resonant path - The path in which sound can continue to bounce back and forth, causing standing waves.
Reverb unit - An echo chamber or electronic/acoustical device that is used to make the sound that goes through it seem like it came from a larger, more reverberant room.
Reverberation - The bouncing of sound around a room until it is completely absorbed.
Reverberation time - The length of time that it takes for the reverberation to be down to one millionth its original strength. It is measured in seconds.
Ring - The signal carrying part of a phone plug.
Sea of knobs - This refers to the large number of rows of knobs that are found on many newer and bigger sound mixers. These knobs all do things to the audio and most audio people know what they do. However, with so many knobs it is hard for most other people to understand what they are all for.
Sensitivity - A term used with microphones to indicate how well a microphone will pick up the sound from the voice or instrument. Sensitivity is affected by such things as distance to the sound source, manufacturer (some mics just pick up better than others), gain on the amplifier, directionality, resonance of the room (feedback), etc.
Shelving - A means of rolling off the high or low frequencies. It is similar to a bass or treble control.
Signal to noise ratio - The difference in audio levels between normal audio and no audio. The noise is just the random electrical noise that is in the electronics or on the tape when no sound is wanted. Measured in dB.
Sleeve - The grounded part of a phone plug.
Snake - A long cable that is usually used for multiple microphone lines. It will almost always have a box for microphones to plug into at one end and plugs that go into the sound mixer at the other end.
Source - The place that an audio signal comes from. A microphone or a tape recorder are sources to a mixer. A mixer can be a source to an amplifier.
Spade terminal - End connection for a wire to go under screw terminal.
System noise - The total random noise that comes from an electronic system without any other source of sound.
Speaker - A device that is used to convert an electrical signal to sound waves that can be heard.
Speaker transformer - A transformer used with a speaker to allow a certain amount of sound power to go to the speaker.
Sound reinforcement system - A means of assisting the voice of the communicator so that it may be heard by the audience.
Sound system - The electronic hardware of the sound reinforcement system.
Stage Mix - Adjustment of stage monitor controls affecting balance of sound output to the stage monitor speakers (Musicians and Singers)
Standing Wave - The appearance that the sound wave from a pure tone is not moving anywhere. It produces spots where the pure tone is loud (called a lobe) and other spots where the same tone cannot be heard at all ( this is a null). These spots will occur at distances of only a few inches to a few feet apart, depending on the wavelength of the tone. It will be difficult to tell the direction that these tones are coming from because these waves are not moving.
Stereo - A method of producing sound where the audio is mixed in two different channels. This is so that the human ears can detect direction that the sound is coming from. Usually it is used with music to give a fuller, more natural sound. It has two separate audio channels.
Stereo chorus - A special effect that produces a fuller sound to music by using a delay and modulating the frequencies. It uses a longer delay than flanging.
Stereo microphone - A microphone that is used to receive a stereo sound. It is usually two directional microphones in the same package.
Stereo power amplifier - Two mono power amplifiers in the same box.
Sub master - A secondary master control that sends its signal to the master level control.
Sum - The addition of several signals together.
Sum control - The control that adjusts the level of several signals that have been added together.
Tape - A storage medium that is used to record audio. Also used to play back music and messages through the sound system.
Tape in - Input to the mixer that uses the audio from the output of the tape recorder.
Tape machine - A device that uses the magnetic storage medium of tape to make a record of the audio that is on the sound system, or else uses what has already been recorded on the tape to play back the stored audio onto the sound system.
Tape monitor - A means of hearing what has been or what is being recorded on tape. It is also the control knob on a mixer that can adjust the level of sound that is being used to monitor the tape.
Tape out - Special audio output from the mixer that goes to the tape machine. Some mixers don't have this so the tape machine uses the audio output from either the mixer or the amplifier.
Tip - The signal carrying part of a phone plug.
Track - A part of the audio tape that has one channel of audio recorded onto it. It is in parallel with the length of the tape. On a standard stereo audio cassette there are four tracks, two for each direction.
Transformer - A device used to change the voltage, current or impedance of an electronic circuit. The power stays relatively the same both into and out of the transformer. Common uses are for microphone impedance matching, speaker power matching and plug in power supplies.
Trim, input - A volume control on the input to a mixer that will control the amount of audio signal that goes into the electronics. It is used so that the signal will not be so weak that you can hear the electronic noise in the circuitry and not so strong that the circuitry will clip the audio signal and distort.
Tweak - Another term for adjustment.
Tweeter - A speaker that is used for high frequencies.
Unbalanced microphone - A term used to describe the number of wires used in the mic cord between the microphone and the amplifier. There is one wire in the center and the other wire is also the shield. High impedance microphones are usually unbalanced.
Volume - This is how loud the sound is.
Volume control - The knob that controls the gain or loudness on a mixer or an amplifier. Another term is level control.
Volume unit - The long name for VU.
VOX - Voice actuated relay. It turns on when audio is present and turns off when audio is not there.
VU - A method of measuring audio on a piece of equipment. 100 VU is 100 percent of the audio that is supposed to be there. The level should not exceed 100 VU. This is used in recording and broadcasting, not sound reinforcement.
VU meter- A means of measuring the VU in a piece of equipment. Cannot be use for sound reinforcement but it is used extensively in broadcasting and recording.
Vocal microphone - A hand held microphone that is designed to be used with a person's voice. It has a bass roll off to help compensate for the proximity effect of a bass boost when held near the mouth. It also has a slight high frequency boost to help with clarity.
Wide band - Audio or sound that covers the human hearing range of 20 Hz to 20 KHz.
Wireless microphone - A microphone that uses a radio transmitter either inside the case of the microphone or worn as a small body pack. This radio transmitter sends the signal from the actual microphone to a receiver a short distance away so that there doesn't have to be any wires that tie down the user of the microphone.
Woofer - This is a speaker that is used for low frequencies.
XLR - A type of connector that has 3 pins along with the metal case. Commonly used for balanced microphone connectors where pin 1 is ground or shield, pin 2 is plus and pin 3 is minus.
70 Volt - A type of output from the amplifier that can be used for distribution of the sound to the speakers in the building. Usually not used with the main speaker. Other outputs from the amplifier are 4 ohms, 8 ohms, 25v and tape out.
250 Ohm - A common impedance for a low impedance microphone.
600 Ohm - The standard impedance for low impedance, balanced, line level audio signals.
10K Ohm - The standard impedance for high impedance,
unbalanced, line level audio signals. It is also the standard
impedance
for high impedance microphones.
