Car Audio Dictionary (A-M)
The first part A - M of our audio dictionary.
You may discover that there are many car audio associated terms that have been missed out. Unfortunately if we were to attempt to include every possible entry its likely we would still be working on this first part 6 months from now. If you can think of a term, that isn’t listed below, that you would like explained or think should be included you can either…
- Send us an email requesting that a term be entered into the dictionary
- Email us a term together with an explanation. It will then be edited (if required) and added in with credit given to the author.
Ai-net
Connection type used exclusively by Alpine to connect its components together (excludes amplifiers). Standard and fiber optic options are used. Examples include: Head Units, Equalizers and CD-Stackers. Etc
Amp or Ampere
Unit of Measure for electrical current flow (electron flow). The electrical equivalent to measuring flow of water through a hose. i.e. 20 Litres an hour. Increasing pressure (volts) or reducing resistance (ohms) increases current flow (Amps).
Amplifier
Electronic device primarily used to increase signal wattage. Higher wattage produces more magnetic force and therefore more cone movement in speakers. Result, louder sound re-production and increased control.
Axis
Refers to mounted speaker angle. Door speakers are referred to as “off axis” when they face across the cabin to each other. Door speakers that are “on axis” are angled upwards toward the driver/passenger.
BBE
Sound enhancement technology by Barcus Berry Electronics.
“All music that is amplified through a loudspeaker suffers some loss of fidelity - or subtle distortions - caused by the inherent characteristics of the loudspeaker itself. The BBE system addresses these problems by compensating for phase and amplitude distortions and, in effect, delivering the signal to the speaker in a form which allows it to reproduce the original live performance more fully and more faithfully.”
Link: www.bbesound.com
Box/Enclosure
Most often used in the installation of bass drivers. The properties of a box directly affect the suspension abilities of the driver. i.e. a small box will provide a firmer cushion behind the driver/speaker and therefore change the way it performs and sounds. Boxes are therefore used to tune the sound of the driver and provide assistance to the speakers suspension to prevent the cone movement from exceeding the speakers limits.
Components
Set of drivers, each designed specifically to reproduce a specific frequency range. Usually consists of either a two speaker set (mid and tweeter) and crossover or three speaker set (midbass, mid and tweeter) and crossover.
Crossover
Reduces signal either above or below a select frequency point. i.e. 10khz high pass crossover will filter out frequencies below 10khz at a given slope/rate.
Slope is measured in decibels per octave. Common rates are 6db/octave, 12db/octave, 18db/octave, and 24db/octave.
Decibel
The decibel as used in audio terms is a measurement of sound where 0db is the lowest level of sound detectable by human beings. A 1db increase is the smallest detectable increase.
A doubling of electrical power causes 3db more sound. ie 400rms will theorectially be 3db louder then 200 rms into the same speaker.
However because our ears work on a logarithmic scale,a 10db increase of power is needed to cause an audible doubling in sound.
Distortion
Inaccurate reproduction of the music source. Distortion can be introduced at any stage of the audio system i.e. Source unit, amplifiers or speakers.
Driver
Another word for speaker. Final device used to physically reproduce sound normally by movement of a cone, producing sound waves.
Equalizer
Device used to alter signal strength at certain frequency points.
Ideally used to flatten out the volume levels of all frequencies within the car in order to improve overall sound quality. Unlike a square lounge, a car is a far from ideal environment for reproducing accurate sound. Various frequency ranges will be reduced or accentuated by any number of influencing factors. As an example road noise may act to cancel out certain mid bass frequencies. With an equalizer these frequencies can be turned up to compensate for the loss.
Equalizers can also be used (and often are) to change the sound of the music to the users tastes. i.e. Bass heavy
Available in several different adjustable band combinations, such as 7band, 14band or 28band. Also available in two different types, analogue (normally just referred to just as EQ) and digital (digital EQ).
Filters
See Crossovers.
Frequency
Imagine a speaker resting at its zero point or middle position. The cone of the speaker then moves up to a maximum position then down, past the zero point, to a minimum position before returning back to the middle. This is known as one cycle.
If a speaker completed 1 cycle in a single second it would play a 1hz (hertz) frequency or note. If the speaker were to move through 50 cycles each second this would play a 50hz tone. If a tweeter were to go through 12,000 cycles (which is not uncommon) in a second then this would play a 12khz (kilo hertz) tone.
An average person can hear frequencies from about 28 Hz to 18,000 Hz. However, an average song will generally only range from about 35Hz to 15,000 Hz.
Fuse
Safety devices used to protect electrical devices from power surges. In the event of something going wrong electrical resistance may drop very low allowing an extremely high amount of amps (current flow) to flow through a device frying its components.
Fuses contain a small piece of wire designed to burn out in the event of current flowing at higher levels then the fuses rating allows. The connection is then broken and any device connected after the fuse (including wire itself) is saved from destruction.
Fuses are used in two applications in car audio.
One close to the battery to protect amplifier power cables. Imagine you have a 4-gauge power cable running to your amplifiers. The cable passes by a sharp metal edge and gets cut down to the wire. The resistance is reduced to almost nothing, the cable heats up and the coating melts. The superheated wire catches your car on fire and you wake up to your worst nightmare.
It is because of this possibility that you must install a fuse on the wire and close to your battery. If this same situation was to happen the fuse would blow and your car would be saved.
The second application is a fuse mounted on the actual device. These fuses protect the device themselves from the same situation as above.
Gauge
The gauge is the name given for wire sizing. Gauge is not specifically a measurement but each number refers to a certain diameter wire. The smaller the gauge size the larger the wire diameter (0 is bigger then 2 etc). Car audio applications commonly run between 0 - 22 gauge, or Awg (American Wire Gauge).
The larger the wire (or smaller the gauge) the less resistance the wire has to current flow. Just like a larger pipe can flow more water then a narrow pipe. Therefore the more power your car audio devices require the larger the power (and ground) wire should be.
Of course the devices that require the most power is amplifiers. Most other devices will require only a small size (large gauge) wire.
Note: Its important to note that a ground wire should be the same size as the power wire and no smaller.
Head unit (Head deck)
The main audio system controller. Normally the original source of audio (unless connected to a stacker). Normally contains any combination of CD player, MD player, MP3 Player, Tape player and radio receiver. The head unit is essentially the brain of the system and provides the central interface between the user and the system itself.
Hertz
Imagine a speaker resting at its zero point or middle position. The cone of the speaker then moves up to a maximum position then down, past the zero point, to a minimum position before returning back to the middle. This is known as one cycle.
If a speaker completed 1 cycle in a single second it would play a 1hz (hertz) frequency or note. If the speaker were to move through 50 cycles each second this would play a 50hz tone. If a tweeter were to go through 12,000 cycles (which is not uncommon) in a second then this would play a 12khz (kilo hertz) tone.
An average person can hear frequencies from about 28 Hz to 18,000 Hz. However, an average song will generally only range from about 35Hz to 15,000 Hz.
Magnet
The magnet is the engine of the loud speaker. As positive power enters the magnet the speaker’s cone is pulled in. Then as negative power enters the magnet the cone moves outwards. This combination repeated up to 15 thousand times a second produces sound waves for our ears.
Magnets come in all different sizes and power ratings.
Max power
Max power is a power rating used by some companies to rate their products. It is an unreliable rating measured in extreme circumstances often unachievable and unsustainable in a car environment. These measurements are designed to lure the unsuspecting audio beginner. Do not get caught in this trap, always go by RMS or nominal power ratings.
Mid
Refers to either the middle frequency range or the speaker designed specifically to reproduce it. The specific range is not set in concrete but is roughly between 120hz - 5khz.
Mid bass
Refers to either the middle to low frequency range or the speaker designed specifically to reproduce it. The specific range is not set in concrete but is roughly between 80hz - 300hz.
Ideally subwoofers should not reproduce frequencies above 80hz because at this stage bass becomes directional (listener able to detect direction of origin) and most subs are installed in the rear. Mid drivers generally do not reproduce lower frequencies very well because of the construction properties required to handle higher frequencies.
