Keywords from A-Z Flashcards
Alternating Current (AC)
A flow of electricity that continually changes amplitude and direction. An audio signal is an example of an alternating current.
Amplify
To increase the strength of an audio signal (opposite of Attenuate).
Amplitude
The strength of an audio signal. When the signal is turned into sound waves by a loudspeaker, the amplitude is related to volume.
Attenuate
To reduce the strength of an audio signal (opposite of Amplify).
Audio interface
A device enabling analog audio equipment to connect to a computer, consisting of analog-to-digital and digital-to-analog converters.
A/D conversion
Analogue-to-digital conversion
ADT
Automatic double tracking or artificial double tracking
Balanced
A type of connection or cable with two signal wires and a separate earth (ground) wire. This helps to cancel out interference and avoids having one side of the signal connected to earth.
Bit depth
The number of binary digits used to represent each sample, also known as resolution. CD audio uses a resolution of 16 bits. Higher bit depths are sometimes used in recording, which have to be reduced at the mastering stage.
Capacitor
An electronic component that stores an electrical charge between two parallel plates. Only an alternating current can pass through it.
Capacitor microphone
A microphone in which the diaphragm forms one side of a capacitor. When the diaphragm vibrates, the stored charge in the capacitor is disturbed and an electrical current flows.
Compression
A process applied to an audio signal to control sudden peak levels. Example uses include evening out vocal performances and adding ‘punch’ to drum and bass tracks.
Cycle
An audio signal is an alternating current of electricity. One cycle is the change from zero to its highest voltage, then to its lowest voltage and back to zero again.
D/A Conversion
Digital-to-analogue conversion
DAW
Digital audio workstation, e.g. Logic Pro x
Diaphragm
A very thin sheet of material which vibrates easily. Used as part of the mechanism which converts sound to electricity in a microphone.
Direct Current (DC)
A flow of electricity in one direction between positive and negative.
E.g. - a torch where the electricity powers a light bulb.
Dither
A process applied to digital audio when bit depth is reduced, helping to reduce errors and to retain as much information as possible.
Dynamic microphone
A dynamic microphone generates its own electrical signal by vibrating a coil pf wire in a magnetic field.
Dynamic processing
Controlling signal levels using software or hardware such as a compressor.
Effected
A sound signal that has had one or more effects applied to it.
Electromagnet
An electromagnet is created whenever an electrical current flows through a wire. If the wire is coiled and wound around a metallic material the magnetic field s strengthened. Loudspeakers and microphones use electromagnetic effects to convert sound to electricity and back again.
Equalisation (EQ)
The process of filtering, amplifying or attenuating a range of frequencies in an audio signal. Usually in ranges of frequency (bands) such as Bass, Mid and High.
Fader
A linear or rotary control, most commonly found on a mixer to adjust the volume of each channel.
Foldback
A signal sent to monitors on stage or headphones in a studio to enable performers to hear themselves and other pre-recorded or live signals.
Frequency
The number of cycles per second, either in a sound wave or electrical audio signal.
Frequency response
The sensitivity of audio equipment (such as a microphone or loudspeaker) at different frequencies, often represented as a chart. A ‘flat’ response suggests a similar sensitivity across a range of frequencies.
Gain
A measure of amplification. For example, an amplifier may have a gain of 10, meaning that the output will be ten times stronger than the input. This is sometimes represented in decibels. Gain controls are commonly seen at the top of a mixer channel, controlling the channel preamplifier.
Insert point
A TRS socket on a hardware mixer or channel. When a plug is inserted, the signal path is broken. The signal is sent out through one signal wire of the cable and returned through the other signal wire, cleverly using only one socket. It is mainly used to connect a compressor, which processes the entire signal.
Jack
A type of plug/connector with either a Tip and Sleeve (TS) or Tip, Ring and Sleeve (TRS).
Loop
A section of digital audio recording that can be repeated. Often used to create drum tracks and backing tracks.
LFO
Low Frequency Oscillator, applied in modulation.
LPF and HPF
Low Pass Filter and High Pass Filter
LSB and MSB
Least significant byte and Most significant byte
Mastering
The process of preparing a completed mix for distribution.
MIDI
Musical Instrument Digital Interface. A ‘protocol’ (set of agreed standards), that allows electronic instruments such as keyboards, controllers, computers and other electronic equipment to communicate, control and synchronise with each other.
Mixer
A device that combines and controls audio signals from other equipment.
Mixing
The process of balancing, panning, processing and adding effects to a number of live signals or recorded tracks.
Mono
An abbreviation of ‘monaural’ meaning only one audio signal. With mono playback there is no sense of left to right placement of sounds. A small radio with one loudspeaker is an example of a mono device.
Multi-Track Recording
A device that can record a number of audio inputs separately and play back some tracks while recording others.
Normalisation
The process used to increase the level of a digital recording. During normalisation, the computer processor finds the loudest samples and calculates the difference between them and the highest possible level. The difference is then added to all samples, bringing everything up as high as possible without peaking.
OSC
Open Sound Control
Pan
An abbreviation of ‘panorama’. The apparent placement of sounds from left to right, usually achieved by distributing a signal between left and right loudspeakers.
Peak
- The highest level in a wave cycle
2. A digital signal which exceeds 0 dB resulting in a distorted sound (also known as ‘clipping’)
Phantom power
48v for condenser microphones
Pick-up pattern
A circular chart showing the sensitivity of a microphone (when viewed from above) as a sound source is moved around it.
Plugin
Extra small program loaded into powerful software packages to increase their functionality. There will often be a plugin folder in the installation folder. Effects and instruments are often added in this way.
Potentiometer
A variable resistor which limits the flow of an audio signal through it (comparable to a tap controlling the flow of water). Used for volume, pan, EQ, and some other controls in mixers and audio equipment. Also known as a ‘pot’, a potentiometer can be rotary or linear. For stereo signals, two potentiometers are mechanical linked (ganged) together.
Preamplifier (preamp)
A small amplifier that brings out a microphone signal up to useable level at the highest possible quality. Also the first stage in a more complex amplification system.
Pre-Fade Listen (PFL)
On a mixer channel, this switch cuts out the fader and sends the signal straight to the control room output. Used to set up the level of Gain for each channel.
Q
The bandwidth
Quantisation
In a MIDI sequencer, quantisation pulls notes towards a beat or other rhythmic division. This can be full or partial (so as not to sound too robotic) and can even follow a pattern or ‘groove’.
Roll-off
A filter used to cut low or high frequencies. For example, some microphones have a roll-off switch to cut all signals below a certain frequency (e.g. 75 Hz) to reduce noise or ‘rumble’. Named after the shape of the frequency response chart at the point where it ‘rolls off’.
RMS
Root-mean-square
Sample/Sample rate
- The process of converting an analog audio signal to digital data - one sample is the smallest section of audio that is analysed. Sample rate refers to the number of samples per second. In CD quality audio the sample rate is 44,100 Hz
- Recording an individual sound or a short section of some music.
Sequencer
A sequencer records and stores a series of MIDI messages and then players them back to control an instrument. Both the instrument and the sequencer can be software or hardware.
Signal/audio signal
A flow of electrical current that represents a sound as it passed through audio equipment.
Sound module
A MIDI instrument that is played by a sequencer but does not have a keyboard and cannot be played directly.
Sound Pressure Level (SPL)
Very loud sounds produce high levels of air pressure and can damage equipment and hearing. For example, a sensitive microphone could be damaged by the high SPL from a kick drum.
Stereo
An abbreviation of ‘stereophonic’. A sound reproduction technique using two loudspeakers to create the effect of left and right placement of individual sounds.
Synthesiser
An electronic instrument used to imitate the sounds of real instruments or to create new timbres.
Tape
A recording medium consisting of stripes (tracks) of magnetically sensitive material on a reel of plastic or metal tape. As an audio signal is applied from an an electromagnetic tape head, the magnetic state of the track is altered. They are used in tape and cassette recorders.
Tracking
The process of recording individual instruments for a multi track production
Transistor
An electronic component which amplifies an audio signal.
Trough
The lowest level in a wave cycle.
Unbalanced
A type of connection or cable with two signal wires only, one of which is also connected to earth (ground)
Watt
A unit of power. Most commonly used in audio signal showing changes in amplitude and frequency. Audio software will display the waveform of a signal and allow it to be edited.
XLR
A connector used for microphones or other audio signals, most commonly with three pins although some have more or less. The name is derived from the labelling by the original manufacturer and has no relevance to the configuration.
