Audio Glossary J-R
This is the simple, no-frills version. An enhanced hyperGlossary, where many of the terms have images, expanded definitions, cross-referencing and additional explanatory sections, is available in the members only zone. You can try the hyperGlossary demo here.
|
If you would like to suggest a term that does not appear here, or to suggest other improvements, email me. *A reminder about the spelling used on this site and in this glossary. |
Page
last updated
|
|
|
|
|
|
|
|
J
Jack:
Female audio receptacle, or socket designed for male plug.
Jackfield: See Patchbay
JPEG: Short for Joint Photographic Experts Group, and pronounced
jay-peg. JPEG is a lossy compression technique for color images. Although
it can reduce files sizes to about 5% of their normal size, some detail
is lost in the compression.
|
|
|
|
K
L
Leads:
Signal-carrying cables used to connect various pieces of equipment.
Limiter: A compressor set up with a high ratio (in excess of 10:1)
and used primarily to prevent a signal from exceeding a certain pre-set
maximum level.
Line Level: A signal whose voltage is between approximately 0.310
volts and 10 volts across a load of 600 ohms or greater.
Load In / Out: The installation and removal of production equipment
and services at music performance venues.
Loader/Lugger: Person providing labour for the above function whose
responsibility is generally limited to lugging equipment between the production
trucks and the stage or FOH positions. Their job generally does not include
rigging or setting up the equipment, which is the responsibility of roadies.
Lossy Compression: A type of data compression which permanently
discards data that humans supposedly "cannot hear" to create much smaller
audio, video and image file sizes. When the file is decompressed by the
recipient, this compression method replaces the data for the sections
it removed with calculated values to restore the file. The decompressed
file is similar but not identical to the original file.
Low Pass Filter: A circuit that discriminates between high and
low frequencies and allows only the low frequencies to pass.
|
|
|
|
M
Mac:
Apple Macintosh computer.
Master Fader: A fader which controls the overall level of one or
more outputs simultaneously.
Metronome: Adjustable mechanical or electronic device which audibly
indicates tempo. Some electronic versions may indicate beats per minute
(bpm).
MIDI: Acronym for Musical Instrument Digital Interface, a standard
adopted by the electronic music industry for controlling devices, such
as synthesizers and sound cards, that produce music. At minimum, a MIDI
representation of a sound includes values for the note's pitch, length,
and volume, but can also include additional characteristics, such as attack
and decay time.
MIDI files: A computer file format containing musical information
and performance data.
Mic or Mike: Abbreviation of the word microphone.
Microphone: A device that converts sound pressure variations into
electrical signals.
Minidisk: Recording and playback device using small disks similar
to CDs to store audio using lossy data compression to reduce file size.
Mix: Blend of amplified or recorded sounds. In the recording studio,
the process of combining and balancing the signals from two or more tracks
of a multi-track recorder resulting in a final mix or 'master tape'.
Mixing console/desk: A signal-management device which receives,
combines and balances signals, provides control of volume and tone, and
allows routing of signals to selected destinations.
Modem: Short for Modulator -Demodulator, this device modulates
data by converting it to audible tones that can be transmitted on a telephone
wire, and demodulates received signals to get the data.
Monitor Desk: A mixing console located at the side of the stage
which controls the on-stage sound balance through separate foldback speakers
for the performers. The monitor mix, or foldback mix differs markedly
from the FOH mix.
Monitors (Studio): Speakers used in the control room of a recording
studio. Generally of two types: Main Monitors for overall sound, and Reference
Monitors used to check sound quality through less capable speakers, such
as might be found in domestic environments.
Monitors (Live Sound): Foldback speakers and associated amplifiers
used for stage musicians.
MPEG: Short for Moving Picture Experts Group, and pronounced m-peg.
The term also refers to the whole collection of digital compression standards
and file formats developed by the group.
MP3, mp3: Is the file extension for MPEG, audio layer 3. Layer
3 is one of three coding schemes (layer 1, layer 2 and layer 3) for the
compression of audio signals. Layer 3 uses perceptual audio coding and
psychoacoustic compression to remove all superfluous information (that,
in the opinion of the developers, the human ear doesn't hear anyway).
It also adds an algorithm that increases the frequency resolution 18 times
higher than that of layer 2. The result is mp3 encoding shrinks the original
sound data from a CD by a factor of 12 without sacrificing sound quality.
Multicore: Audio or lighting cable containing many bundled leads
allowing signal transmission along separate channels. Also known as 'Snake'.
Multimedia: The use of computers to present text, graphics, video,
animation, and sound in an integrated way.
Multiple Echo: See 'Echo'.
Multi-tracking: The process of recording a multi-part performance
on separate tracks at different times which allows the engineer to subsequently
combine, balance and process those tracks during mixdown.
|
|
|
|
N
Noise
Gate: A special type of expander with a very high ratio (usually about1:100),
often used to eliminate low-level hiss, noise or leakage. Especially effective
wherever there is a high level of ambient noise, such as around a drum
kit.
Non-Lossy Compression: A form of data compression which seeks out
chunks of data which are identical, replacing them with markers called
keys. In this way, the file is reduced in size, and when it is decompressed
by the recipient, the keys are replaced with the large chunks of data
that were originally there (this is called Run Length Encoding). Using
non-lossy compression, the uncompressed file is identical to the original
file.
Nyquist's Theorem: This states that a sound must be sampled at
at least twice its highest analog frequency in order to extract all of
the information from the bandwidth and accurately represent the original
acoustic energy. In practice, sampling at slightly more than twice the
frequency will make up for imprecisions in filters and other components
used for the conversion.
|
|
|
|
O
Ohm:
The basic unit of the measurement of resistance. Symbol used is ‡ (Omega)
Ohm's Law: The law that defines the relationship between current
(I), resistance (R) and voltage (V) in an electrical circuit as: Voltage
equals Amperage times Resistance (V=IR).
Omnidirectional: Capable of picking-up sound equally from all directions
(for microphones) or radiating sound equally in all directions (for speakers).
Outboard Equipment: Audio equipment which is not physically incorporated
into the mixing console. If 'rack-mountable', it is generally located
in an 'effects rack' and can include processors such as reverbs, delays,
external equalisers, compressors, gates and enhancers.
Overdub: To record new tracks on a multitrack recording system
in synchronisation with previously recorded tracks.
|
|
|
|
P
PA:
Public Address system. A sound reinforcement system enabling live performances
to be heard by the audience.
Pad: An electrical circuit used to attenuate or reduce the amplitude
of an audio signal by a fixed amount, e.g a -15dB pad reduces the signal
by a fixed 15 decibels.
Pan Pot: Short for panoramic potentiometer, this is a knob controlling
a voltage divider that can send a signal to a combination of two busses,
such as left and right. Always found on mixing consoles to set up (pan)
a signal within the stereo field, it is also called a 'balance' control
on domestic stereo amplifiers.
PCs: Personal computers. This term is generally used for IBM-compatible,
Intel-based computers running DOS or Windows.
Patch Bay: A panel of jacks (female receptacles) hard-wired to
all inputs, outputs and side-chains of outboard equipment, and all outputs
and insert points of the mixing console. Often used in recording studios
to enable rapid connection of any combination of equipment by the use
of 'patch cords', or 'patch leads'.
Peak Power: A measure of amplifier power based on the amplitude
rise above ground plane or 0 volts.
Peak-to-Peak Power: A measure of amplifier power based on the total
amplitude between peak positive value and peak negative value. Generally
this value is twice the peak value for a symmetrical waveform.
Phantom Power: Operating voltage (usually 48 Volts DC) supplied
to a condenser mic by a mixer or external power source along normal mic
leads.
Phase: The relationship of an audio signal or sound wave to a specific
time reference.
Pick: See Plectrum
Pitch: The subjective sensation produced by various frequencies.
The higher the frequency, the higher the perceived pitch; however, frequency
is not linearly related to pitch. See also 'Concert Pitch'.
Plectrum: Triangular object generally made out of plastic used
to strike the strings of a guitar.
Polarity: A condition with two states (+ve or -ve) and is usually
defined in one of three ways: 1. Acoustical to electrical (microphone):
Positive pressure at diaphragm produces positive voltage at pin 2 of XLR
or at the tip of a 1/4-inch phone plug. 2. Electrical to acoustic: Positive
voltage into the "plus" terminal of a speaker causes the speaker's diaphragm
to move forward to produce positive pressure. 3. Electrical to electrical:
Positive voltage into pin 2 of an XLR jack produces positive voltage at
the output (pin 2 of an XLR plug, the tip of a 1/4-inch phone jack, or
the red (plus) connector of a binding post (banana terminal).
Potentiometer (Pot): A variable resistor (rotary or linear) used
to control volume, tone, or other functions of an electronic device.
Power: In electricity, power (P) is the product of the voltage
(V) and the current (I). i.e. P=VI. The unit of power is the Watt.
Power Amplifier: An amplifier without tone controls, and with a
higher power output than a line amplifier or pre-amp. Commonly used to
drive loudspeakers.
Pre-amplifier/pre-amp: An electronic device used to match an input
signal (such as that from a microphone or guitar pickup) to the input
of a power amplifier. Often built in to mixing console channels as an
initial stage, and generally has tone controls (EQ) to modify the signal.
Production Manager: Person responsible for co-ordination of audio,
lighting and staging requirements, and crew, for any performance. Other
responsibilities may include the scheduling of performances, physical
placement of equipment and management of relevant health and safety matters.
Proximity Effect: An increase in the bass response of some mics
as the distance between the mic and its sound source is decreased.
Punter: Slang for general or common audience.
|
|
|
|
Q
Q: Referring
to the bandwidth of one band of a parametric equaliser, Q is calculated
by dividing the centre frequency in Hz by the width of the boost or cut
zone +3dB or -3dB above or below 0dB. For example, a gentle boost centred
at 1000Hz which extends from 750Hz to 1250Hz measured 3dB above flat has
a Q of 1000/500 = 2. By comparison, a deep notch centred
at 1000Hz which extends from 995Hz to 1005Hz measured -3dB above flat
has a Q of 1000/10 = 100.
Quality: See Timbre
QuickTime: A video and animation system developed by Apple Computer
and built into the Macintosh operating system. It is used by most Mac
applications that include video or animation. PCs can also run files in
QuickTime format, but they require a special QuickTime driver. QuickTime
supports most encoding formats, including Cinepak, JPEG, and MPEG. QuickTime
is competing with a number of other standards, including AVI and ActiveMovie.
|
|
|
|
R
Rack-mountable:
Describes outboard equipment designed to be mounted in a standard 19"
EIA 'Effects Rack'.
Ratio: One of the parameters which can be varied on dynamic range
processors such as compressors and expanders. It represents the compression
or expansion ratio between input and output levels. A compressor with
a 2:1 ratio would reduce the output gain to half of the input value above
the threshold. An expander with a 1:80 ratio would reduce the output gain
to 1/80th of the input value below the threshold.
RealAudio: The de facto standard for streaming audio data over
the World Wide Web.
Recording: Capture and storage of sound for subsequent reproduction.
Reference monitors: See Monitors (Studio)
Repertoire: Compositions and lyrics; musical works.
Reverb: Abbreviation for reverberation, a complex blend of multiple
interacting reflections within an enclosed space which combines with the
direct sound from a source and defines the character of the sound in a
room or hall. It is also used for a signal processor which can generate
an approximation of natural reverb. (Caution: do not confuse with 'Echo'
- a different effect altogether.)
Rhythm section: Section of the band which is responsible for laying
down the beat, usually consisting of the drummer and bass player.
Riff: A short repeated musical phrase or figure.
Rigger: Person licensed to supervise the fixing and securing of
heavy loads, such as lighting or sound systems which may need to be suspended
or 'flown'.
Ripper: A software program that "grabs" digital audio from a compact
disc and transfers it to a computer's hard drive. The integrity of the
data is preserved because the signal does not pass through the computer's
sound card and does not need to be converted to an analog format. The
digital-to-digital transfer creates a WAV file that can then be converted
into an MP3 file.
RMS: Root Mean Square: A method of calculating the average
power generated by a sinusoidal waveform. Used for comparing amplifier
power, it is a more realistic measure than 'peak' power or 'peak-to-peak'
power.
Room EQ; Room Tuning: The process of compensating for acoustic
deficiencies in both venues and PA systems using graphic equalisers in
FOH and foldback signal paths.
RT60: Means 'Reverb Time - 60dB' and indicates, in seconds, the
time taken for a continuous sound, which suddenly stops, to decay by 60dB.
Used as a measure of the reverb decay in a room or hall. A bedroom may
have an RT60 of 0.5 sec; a large hall may have an RT60 of 3.0 sec or more.
RU: Stands for 'Rack Unit': standard front panel height (1.75"
or 4.44cm) used for pro-audio equipment to enable mounting in an equipment
cabinet - see Effects Rack.
Run-Length Encoding: See Non-Lossy Compression.
|
|
|
|
|
|
So if some words don't look quite right to you, relax. We're not dyslexic, we just use Standard Oxford Dictionary spelling, not Websters.
HyperGlossary
see what the
members are
getting!
Studio
reviewers
wanted
Have
you recorded at a studio recently? Write a studio review to appear in
our members' zone.
Audio
School
reviewers wanted
Have you completed an audio course recently? Write
a review of your course for others who may benefit from your experiences.