Glossary of Audio Terms

See also the EnglishTranslations page, for common abbreviations of everyday phrases.

This page contains English words, both technical and non-technical, commonly used in audio. It should also serve as an index to various sections of the Wiki. I hope that this page is useful to both native English speakers and others. Therefore, wherever possible, please:

• keep all explanations in simple English
• include links in descriptions
• put entries in alphabetical order!

Where a topic is controversial, please make a separate page (or start a DiyAudio? thread) for discussion, to avoid filling up entries with clutter.

A

• Amplification

The process of increasing the magnitude of a signal.

• Attenuation

The process of decreasing the magnitude of a signal.

B

• Baffle

1. Technically, any part of an enclosure designed to stop sound waves from the rear of a driver interfering destructively with those from the front, which reduces sound output at low frequencies. 2. Informally, the board on which the driver is mounted.

• Bass-reflex enclosure

A type of enclosure where the driver is mounted in a box containing a port (or vent). The port resonates at a low frequency (see Helmholtz Resonator), and thereby gives extended bass response compared with the equivalent sealed box.

• Bridged

Multiple amplifiers running in series to double the maximum power (quadruple the power at a specific voltage gain). Bridging two amplifiers is typically done by feeding one amplifier an inverted signal, connecting the negatives of each amplifier together, and connecting the load between the positives.

C

• CCS (or Constant Current Source)

A circuit designed to draw a specific, constant amount of current independent of the voltage applied.

• Complementary Pair

A pair of oppositely polarized transistors created to closely complement (but rarely match) the specifications of each other.

• Crossover

An electrical circuit designed to split an incoming signal into frequency bands, one for each driver in a loudspeaker system.

D

• Dampen

To reinforce material in a system in such a way as to make it less prone to resonance. May include bracing or covering with a soft material.

• Diff Amp (or Differential Amplifier)

An amplifier that only amplifies the difference between two or more input signals.

• Driver

A loudspeaker unit: the part consisting of a motor and a cone (etc) i.e. not including the enclosure . See LoudspeakerAnatomy.

• Dynamic

1. When applied to a transducer, means that movement is converted to or from an electrical signal by the action of a current-carrying wire in a magnetic field. Opposite of electrostatic.

E

• Enclosure

The box in which one or more drivers are placed to make a complete loudspeaker.

• Electrostatic

1. When applied to a transducer, means that movement is converted to or from an electrical signal by electrostatic attraction or repulsion between two charged conductors. Opposite of dynamic. See Electrostatic Loudspeakers.

F

• Filter

1. A circuit made up of resistors, capacitors and/or inductors to change frequency response, phase response, or other characteristics of a given signal.

G

H

• Helmholtz Resonator

A vessel containing air with an open neck or hole will have a resonant frequency, with the air inside it acting as a gas spring; this is a Helmholtz resonator. The resonant frequency depends on the volume of air and the dimensions of the hole. [Click Here for a useful page on the topic].

• Horn

A type of enclosure where the driver is coupled to the air via a tube whose area increases along its length. See basshorn.

I

• I/V stage
• Infinite Baffle

A type of enclosure where the driver is mounted inside a sealed box. Contrast with open baffle.

• Input Stage

First of three amplifier subsections as defined by Lin.

J

K

L

• Labyrinth

A form of transmission line where the wave guide has been folded a number of times, to reduce the external dimensions.

• Lin Topology

Amplifier electronics defined as three separate subsystems: Input Stage, VAS, and Output Stage, each providing it own separately defined contribution to the whole amplifier circuit.

• LTP (or Long Tailed Pair)

<define me please>

• Loudspeaker

A device or system for turning an electrical signal into sound waves in air. See the Loudspeaker page. The term loudspeaker may refer to a driver on its own, or a complete unit consisting of driver in an enclosure. The term transducer is more usually used when the sound waves are in water, solids, etc.

• Load

The device connected to the output of an electrical circuit, such as a loudspeaker.

M

N

O

• Open Baffle

A type of loudspeaker which consists of the driver mounted on a baffle which is open at the rear, usually a large flat or curved board. Contrast with infinite baffle.

• Output Stage (or OPS or Output Section)

Third and final stage of Lin amplifier topology. Load, usually loudspeaker, is connected to the output of this stage.

P

• Pole Frequency

<define me please>

• Port

A hole, or length of tube, put in the wall of a bass-reflex enclosure.

• Preamplification

An amplification stage only intended to raise voltage. Preamplifiers are not to drive tough loads like speakers.

Q

• Quasi-Complementary

<define me please>

R

• Resonance

1. Excitement of a material or system that results in an oscillation at the resonant frequency. Dampen the system to help with resonances.

• Resonant Frequency

1. The center frequency that when applied to a system, results in resonance. Any given system may have several resonant frequencies.

• Ribbon

A type of loudspeaker in which a current is applied to a thin metal "ribbon" within a magnetic field usually created by two magnets beside the ribbon. The current creates a magnetic field from the ribbon, which will move it within the static magnetic field.

S

• Sealed Box

Same as Infinite Baffle.

• Speaker

Same as loudspeaker.

T

• TQWT

Tapered Quarter Wave Tube. A type of enclosure combining features of both a transmission line and a horn.

• Transducer

Any device which converts sound waves into electrical signals, or vice versa. See louspeaker, microphone.

• Transmission Line

A type of enclosure where sound waves from the rear of the driver are guided into a long, possibly tapering, tube. [Click here for a website devoted to Transmission Line speakers].

• Tri-mode

A tri-mode amplifier is when two channels of an amplifier are run independently for midrange/treble, but are also bridged for running a (sub)woofer. It is the same as bridging the amplifier, but you keep the midrange/tweeters on their respective channel outputs.

• Tweeter

A driver used to reproduce treble frequencies.

U

V

• VAS

Voltage Amplifier Stage. Second stage of Lin amplifier topology.

• Vented Box

Same as bass-reflex enclosure.

• Voigt Pipe

See TQWT.

W

• Woofer

A driver used to reproduce bass frequencies.

X

• XO

Abbreviation for crossover.

Y

Z

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