Audio glossary

In this brief glossary we explain some of the key terms that will help you understand more about audio technology. Think something is missing? Let us know at

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AACShort for "Advanced Audio Coding". This audio format allows for more sound quality than an mp3 file with the same data size.
Acoustic powerAlso known as sound power, this is an acoustic value that indicates the sound energy per time unit of a sound source.
Active speakersDesignation for a loudspeaker that contains its own integrated amplifier.
Air gapIn loudspeaker construction, the air gap is the narrow gap between permanent magnets in which the moving coil can vibrate.
ALACShort for Apple Lossless Audio Codec. Designation for a sound format developed by Apple for lossless data compression compared to the original signal.
AmbienceDiffused background noise in film/radio/television, such as road noise.
AmplifierCommon term for a device that amplifies incoming audio signals to make them audible.
aptXQuality feature of an audio signal transmitted via Bluetooth. The original signal is transmitted in CD quality.
ARCShort for Audio Return Channel. Enables two-way signal transmission with just one HDMI cable.
ASMRShort for "Autonomous Sensory Meridian Response". Indicates a sensory reaction which can be triggered by specific sounds, such as whispering.
AudiogramAlso known as the hearing curve, this describes a person's subjective (frequency-dependent) hearing ability.
Auditory perceptionThe holistic sensory perception of sound.
AUXThe AUX input (aux is short for auxiliary) is an analogue input for stereo audio signals.
Background noiseDesignation for the inherent noise of an audio system without a current useful signal.
Banana plugsColloquial term for 4mm R-pin. Connects detachable loudspeaker cables e.g. to an amplifier.
BandBand is an abbreviation for frequency band and refers to a certain small frequency range within a larger total frequency range.
BassThe frequency range of audible sound below about 200 Hz.
Bass reflex tubesBass reflex speakers are loudspeakers that amplify sound waves (usually) radiated through tunnel-like openings by reflection.
BeadThe bead is the part of the speaker that connects and seals the diaphragm and basket.
Beats per minute (bpm)Describes the tempo of a piece of music.
Bi-ampingSpecial cable connection method between amplifier(s) and speakers. In bi-amping, two power amplifiers are connected to a pair of loudspeakers, with each amplifier amplifying its own frequency range.
Bit rateThe bit rate is the output quantity of audio or video signals for digital multimedia formats per time unit. The unit of measurement is called "bit per second" (bit/s or bps).
Bi-wiringSpecial cabling method between amplifier and speakers. With bi-wiring, individual frequency ranges are divided into different cable paths and fed together to the loudspeaker.
Dynamic speaker with a cone-shaped membrane, i.e. as a domed cone.
CapacitorA capacitor is an electrical component which stores electrical charge. It is used in crossovers for loudspeaker construction.
CECShort for "Consumer Electronics Control". CEC is a cross-device control of at least two devices connected via HDMI with one remote control.
ChassisTerm for the fixed housing of a loudspeaker.
CinchStandard connector for audio and video connections.
ClippingClipping happens when the amplifier is overloaded. The signal level is so high that the diaphragm strikes. This results in an unclean sound.
Coaxial driverThe coaxial driver consists of at least two drivers arranged on a single axis. Acoustically, this is an advantage, as the coaxial driver acts as a point source of sound and therefore produces a more natural playback.
Comb filterA filter that can pick out pre-defined frequencies from sound signals.
Cone speakerA common form of speaker in which the loudspeaker diaphragms are designed in a conical shape.
Critical frequencyThe upper or lower limit of the frequency range up to which a speaker can reproduce an undistorted sound signal.
CrossoverThe crossover is a component in a loudspeaker that divides electroacoustic input signals into different frequency ranges and feeds them to the corresponding drivers.
D/A ConverterAbbreviation for digital-to-analogue converter. This component converts digital to analogue audio signals. They are also often called Digital Analogue Converter (DAC).
DAB/DAB+Short for "Digital Audio Broadcasting". Transmission standard for terrestrial reception of digitally transmitted radio stations.
DecibelDecibel (dB) is a unit of measurement for the loudness of a sound, named after Alexander Graham Bell.
DecouplingLoudspeakers can be decoupled from the floor to reduce the transmission of vibrations to the floor.
DiffractionWhen sound waves hit an obstacle or an object with an opening, the waves behind the obstacle are physically diffracted.
Direct emitterA direct emitter is a loudspeaker that emits sound in only one direction.
DiscmanColloquial term for a portable CD-Player, originally developed by Sony.
Distortion factorThe harmonic distortion factor indicates how much the output signals deviate from the input signals, i.e. by what percentage they are distorted.
Dolby AtmosThe latest Dolby sound standard for home cinema. With Dolby Atmos, an unlimited number of sound tracks can be created in theory. Special attention is paid to a new sound layer - the sound can now come "from above".
Digital (Plus)
This is the Dolby codec for the digital transmission of 5.1 audio signals, especially during streaming. The newer Dolby Digital Plus standard also allows the transmission of 7.1. sound signals.
Pro Logic
Describes an audio codec from Dolby. Dolby Pro Logic can decode room sound information from a stereo source.
Dolby SurroundDolby Surround is an outdated analogue multi-channel sound system that can accommodate four audio channels in two soundtracks.
Dolby VisionDolby TrueHD was developed by Dolby Laboratories specifically for the soundtracks of HD DVDs and Blu-ray Discs. According to the manufacturer, it is lossless.
Down-firing subwooferIn a down-firing subwoofer, the speaker cone is directed towards the floor. The sound signal is immediately reflected and thus more homogeneously perceived.
DPU TechnikBass reflex technology developed by Teufel in order to avoid flow noises.
DSPShort for "Digital signal processor". Computer chip for sound control.
DTS HDShort for "Digital Theater Systems High Definition". DTS HD is a multi-channel digital audio system, specifically designed for Blu-Ray discs and HD DVD, and the competing format to Dolby True HD.
DTS:XDTS: X is a sound format based on audio objects and is therefore not bound to a certain number of speakers. This sound format is an alternative to Dolby Atmos.
DynamoreDynamore is a patented method developed by Teufel for psychoacoustic sound enhancement.
EchoAn echo is audible when reflections from a sound source are delayed so much that the ear perceives the sound as an independent sound event.
Emission angleThe emission angle is the area in front of a loudspeaker in which the sound is best heard.
EqualiserAn equaliser (EQ) is an analogue or digital user interface that allows you to manually change individual frequency ranges, for example, to emphasise the bass.
FadeA slow, manual or automatic change of volume.
FLACShort for "free lossless audio codec ". FLAC is an audio format for lossless storage.
The frequency range indicates an exactly defined range between and the highest tone in which a loudspeaker can reproduce measured or audible signals. For example, from 45 - 20000 Hz.
Front-firing subwooferA subwoofer in which the signal is output to the front.
GhettoblasterAlso known as a boombox, a portable music system known from the 80s, mostly with cassette deck and radio function.
Haas effectThe Haas effect, or the Precedence Effect, is a Psychoacoustic Effect described by Helmut Haas as the ability of our ears to localise sounds coming from anywhere around us.
HDMIMulti-vendor interface to transmit (especially) video signals. Abbreviation for "High Definition Multimedia Interface".
HDRShort for High Dynamic Range. Dynamic image contrast control on monitors. HDR requires HDMI 2.0 or higher.
HeadsetA headset is a pair of headphones with an integrated microphone.
Hertz (Hz) is the (derived) physical unit for the frequency. In Hertz, the number of repetitive oscillations per second is displayed. Named after the German physicist Heinrich Hertz.
Hi-FiShort for High Fidelity. Hi-Fi is a quality standard in sound engineering.
Hi-Fi rackA Hi-Fi rack (also called a Hi-Fi shelf) is a piece of furniture mostly for private use, on which audio devices such as amplifiers, receivers, etc. can be placed.
Horn speakersA horn loudspeaker is a type of speaker in which one or more drivers are designed in the form of a funnel (like a horn). Horn loudspeakers have a high dynamic range and low power consumption.
In-earsPopular headphone construction. The hearing pieces are inserted directly into the ear canal for listening.
InterauralLatin for "between the ears". This term plays a role in describing the localisation of auditory events.
InterferenceInterference is a superposition of at least two sound waves of the same frequency.
Jack plugJack or jack plugs are connectors used worldwide in audio technology for audio signals.
JitterJitter refers to the fluctuation of the stroke frequency, which can have a negative effect on the sound.
LimiterA device that limits the maximum amplitude of a signal.
Low frequencyFrequencies between 20 - 20.000 Hz.
MDShort for MiniDisk. Older form of memory hardware.
MembraneThe part of the speaker that produces the audible sound or sound waves.
MIDIShort for „Musical Instrument Digital Interface". MIDI is a digital interface for the synchronisation of electronic musical instruments or effect devices.
MinimoogThe minimoog is an instrument that was invented by physicist Robert Moog in 1970.
Moving coilA moving coil is the drive unit of a loudspeaker.
mp3Worldwide popular compression method for audio files.
Multi-room audioMultiroom systems are interconnected loudspeakers (possibly in different rooms) which can be controlled by a central unit.
Music cassetteOlder storage medium for sound recordings.
Neodymium magnetA magnet made from the chemical element neodymium, which is highly rare. Neodymium magnets are particularly well-suited for loudspeaker construction because they can generate strong magnetic fields in small volumes.
Noise-cancelling headphonesIn acoustics, noise cancellation is usually associated with headphones. Noise-cancelling headphones are designed to reduce external noise. They use passive and active technology.
OhmUnit of electrical resistance. In loudspeaker construction, the (acoustic) impedance is indicated in ohms.
On-ear headphonesCommon headphone design. The receiver is placed directly on the ear, but does not completely cover the ear.
Optical cableUsed for the optical transmission of signals. The light signals are passed through a mixture of quartz and glass, known as optical fibres.
Over-ear headphonesHeadphone construction. Like on-ear construction, however, covers the entire ear.
Typical passive loudspeakers require the signal from an external amplifier for sound reproduction.
PickupIndicates the front part of a record player needle, which is used to read sound signals stored on a record.
Power amplifierA power amplifier is a Hi-Fi component that only encloses the audio signal amplifier.
Pre-amplifierA pre-amplifier is a Hi-Fi component that prepares audio signals from different sources for output to the power amplifier.
Rear speakerRear speakers are the loudspeakers in a typical 5.1 home cinema configuration that are used in the rear area starting from the listening position. They are often referred to as effect speakers or surround back.
ResilienceDescribes a power value in Watts that can be absorbed by a speaker.
The resonance frequency is the frequency at which the amplitude of an oscillating system is greater than that of the impulse of adjacent frequencies.
ReverberationReverberation is an acoustic phenomenon in room acoustics. Reverberation is caused by reflections of sound waves on surfaces.
This phenomenon can occur when connecting several devices and is usually audible as a humming noise.
Room acousticsRoom acoustics denotes the acoustic properties of a room. Important factors are reflection, absorption and diffusion of the sound.
Room modesTerm for superposition of sound waves.
SCARTSCART is a somewhat outdated standard for connectors between audio and video devices.
Silent discoIn a silent disco, visitors listen to the music via headphones. This allows events to take place where loud music is not allowed, for example in public spaces.
Sound cardHardware for laptops and desktop computers to generate and output audio signals.
Sound emissionIn acoustics, sound emission is defined as the output of sounds from a sound source.
Sound filterAnother name for an equaliser
Sound pressure levelThe sound pressure level is a logarithmic parameter describing the strength of a sound source.
SPDIFDesignation for an optical interface via which sound signals can be transmitted by means of fibre optic cables. Another designation is TOSLINK.
Sweet spotA sweet spot refers to the (listening) position in a room where the sound of a sound system is perfectly audible.
THXQuality guidelines for cinema sound initiated by Hollywood director George Lucas (Star Wars) with the basic idea that film sound should sound equally good in every cinema.
TOSLINKDesignation for an optical interface via which sound signals can be transmitted by means of fibre optic cables. Another name is S/PDIF.
Ultra HD BluRayUHD or 4K resolution is a resolution standard that can display up to 3,840 x 2,160 pixels instead of the conventional Blu-ray, which can display "only" 1920 x 1080 pixels.
USB-AudioInterface for the transmission of audio signals via USB.
VESAAbbreviation for "Video Electronics Standards Association". VESA is a standardised settings for mounting flat screens, among other things.
field synthesis
Wave Field Synthesis (WFS) is an acoustic reproduction technology that generates virtual spatial sound environments through wave fronts.
Colloquial term for wireless transmission of HDMI signals.
XLRAlso known as Cannon plugs, XLR is an industry standard for electrical connectors in professional sound reinforcement and recording studio technology.
2-way speakerIn this kind of loudspeaker, two drivers (usually a tweeter and a woofer) divide the frequency range to be reproduced.
3-way speakerA loudspeaker that has its own driver for high, medium and low frequencies.