Speaker Design, Speaker Building: Loudspeaker Design & Construction

Glossary of Loudspeaker Terms

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Speaker Design Terms used on this site

Amplifier

Essential section of hi-fi, Boosts and manages signals to drive speakers.  Can be one-box (integrated) or have separate pre and power sections.

Analogue

LPs/cassette tapes store audio in non-digital form directly related to the signal.

Bass

Low frequencies, often tricky to reproduce.  The ideal for this deep sound is good bass extension (ie low down) allied to speed and rhythm.

Bass reflex

A speaker design using air-flow from a port in the cabinet to help low frequencies.

Biamping

Each drive unit of a speaker is driven by a separate amplifier channel, so a pair of two-way speakers needs two stereo amplifiers, and two runs of cable to each speaker.  See biwiring.

Binding post

Speaker terminal with threaded collar for gripping bare wires and sometimes a socket for banana plugs, too.

Biwiring

Some of the benefits of bi-amping but at a lower cost.  You need speakers with two sets of inputs and a split crossover, then send twin runs of cable from amplifier to each speaker.

Cables

Copper conductors are mostly used with purity expressed as a number of 'nines'.  So 'six nines' or '6N' purity might be 99.99997 per cent pure copper.  Good speaker cables can have many strands (multistrand) or one or more thick wires (solid core). 

CD-R

CD-Recordable.  Uses a special blank disc in a recording CD player.  Once recorded it can't be erased, but plays in standard CD players when recorded.

Coloration

A shift away from the natural rendition of music.  Coloration is undesirable - 'boomy' bass, a 'nasal' midband or a splashy treble, for instance.  All colorations get in the way of the music.

Compact Disc

Standard 12cm disc, which stores information digitally, read by laser optical system.  Originally designed for music storage the CD is now used for many applications such as CD rom for computer data.

Crossover

Circuit inside speakers which splits high frequencies to the tweeter and low to the woofer.

Decibel

(dB) Measures changes in sound pressure exponentially.  A change of 1dB is just about audible, while +10dB sounds like the level has been doubled.

Digital

Method of storing music and data in 1’s and 0’s which is more reliable than analogue and has more uses.

Distortion

Unwanted signals or signal changes added by equipment, especially during overheating or using too much volume with speakers.

Dolby Pro-Logic

Home cinema: uses an extra centre speaker at the front, which locks dialogue to the screen.

DVD

Digitally Versatile Disk.  Designed for home entertainment, they play on consumer DVD players that plug into TV sets, or on desktop PCs equipped with a DVD-ROM drive and the requisite hardware/software.  Contain multichannel soundtracks fro home cinema.

Dynamic range

The range, in dB, between the largest and smallest signals reproduced by hi-fi or speakers.

Frequency

High-pitched sounds have a high frequency, low-pitched ones a low frequency.  Audible sounds range from around 16Hz to 20kHz.

HDCD

High Definition Compatible Digital - a coding system for CD which aims to get better sound.  Needs a decoder to hear the full effects.

Hertz (Hz)

Unit of frequency.  One Hz means a signal has one cycle per second.

Horn loading

Improves a drive unit's efficiency and output, using a structure within the speaker shaped like a horn.  Works like the trumpet on an old-fashioned gramophone

Impedance

Electrical property.  A low impedance draws a high current flow from the source, while a high impedance draws a little.  This means that speakers with a low impedance (lower than 6-8ohms) are more difficult for an amplifier to drive.

In-phase

This means the drivers of both loudspeakers channels, or air-waves, are moving in the same direction at the same time.  Out-of-phase means they are opposing each other, and is not generally desirable.

Midband

Frequency range where most of the instruments and voices are heard.  Vital if singers, etc, are to sound natural.

MiniDisc

Sony's 64mm disc that can record up to 80 minutes of sound.  Looks like a mini computer disc but works optically, like CD, on prerecorded discs, or magneto-optically in the case of blank software.

Nicam

CD-quality digital stereo television sound transmitted alongside the picture.

Ohm

Unit of resistance to current.  Impedance of a speaker is measured in ohms - generally the lower the figure the harder it is to drive.

Power handling

The maximum safe power for speakers.  However it is easier to damage speakers with an amplifier of too low power driven hard, than with too much power (due to the amplifier ‘clipping’ or distorting the wave-form at high volume).

Shielding

Keeps a conductor or equipment away from interference.  Enables speakers to be used near to sensitive CRT (cathode ray tubes) used in TV’s and computer screens.

Subwoofer

A separate woofer box to produce the deep bass sounds smaller speakers can't reach.  More popular in home cinema applications.

Transients

Short and sudden events in music (eg a cymbal crash).  Difficult to reproduce for loudspeakers.

Treble

High frequencies sounds, for example the ‘tish’ sound of symbols.

Triamping/triwiring

Like biamping and biwiring, but for three-way speakers.  Needs three runs of cable in the case of triwiring and three stereo amplifiers if you want to triamp the speakers.

Tweeter

The drive unit handling the treble.

Watt

Unit of power.  More watts mean more power, but how loud a speaker sounds also depends on speaker sensitivity and room characteristics.

Wavelength

The length of a (sound)wave.  For example sound at 50Hz in air has a wavelength of around 6.9 metres, and therefore your room must be this big for you to hear it properly.

Woofer

The large drive unit in a speaker to produce bass frequencies.

 

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