The ABCs of Car Audio

A List of Car Audio’s Most Important Terms Broken Down by Letter

When people are Google searching “car audio near me” looking for the area’s most prominent resource of high-end aftermarket car stereos and best-in-class car speakers, Stereo Depot usually comes up right at the top of the list.

Not only can we handle car audio installation on practically any vehicle you put in front of us, but our team is comprised of some of the most knowledgeable car audio experts in the San Diego area. Every single last one of us is a pure audiophile that’s happy to share our passion for perfect sound.

To offer up some of our industry expertise, we’re breaking down the ABCs of car audio. This is a list of some of the most frequently used terminology and concepts you’ll hear about when discussing car stereo systems, speakers, and other equipment.

A - Amplifier

Referred to as an amp for short, this piece of equipment lives up to its namesake by amplifying the audio signal that’s sent to it from your stereo. The end result is clearer, crisper, more powerful playback.

B - Bass

Bass is anything relating to your low-frequency output. The approximate frequency range is 60 to 250 Hz. For those of you looking to improve your bass output, look into upgrading with subwoofers (mentioned below).

C – Coaxial and Component Car Speakers

We’re doubling up on the letter C because both of these terms get mentioned a lot when it comes to talking about car speakers. Coaxial speakers are an all-in-one speaker unit; they include a tweeter, woofer, and crossover. Component speakers, on the other hand, separate these elements of the speaker. Coaxial speakers are generally easier to install and less expensive. Component speakers offer more customization options but can be on the pricey side.


When discussing car audio installation, you will hear the term DIN a lot. It stands for Duetsch Industrie Normen, but what you need to know is that it’s a reference to the opening that your stereo will fit into. A standard DIN opening is 2” x 8”. A double DIN opening is 4” x 8”. Most modern in-dash units fall into the double DIN category.

E - Equalizer

Referred to as EQ for short, this is a method of tuning your car stereo’s sound by giving you control over a multitude of frequencies beyond the standard bass, treble, and midrange controls. In layman’s terms, the more EQ settings you have, the more you’ll be able to sculpt the playback of your music.

F - Frequency

Frequency response is generally divided into three segments. They include bass, mid-frequency (aka mid-range), and treble.

H - Head Unit

Head unit is one of the many names that’s used interchangeably for a car stereo. Others include in-dash unit and receiver. Regardless of the name you call it by, this is the main attraction in your overall car audio set-up.

I - Isobaric Speakers

Introduced by Harry F. Olsen in the early 1950s, isobaric speakers are a mounting technique in which two or more identical speakers operate simultaneously as a single unit. The woofers should contain a very small air chamber when mounted, which would make them almost incompressible.

J - Joule

A joule is a unit of electrical energy that equates to the work done when a current of one ampere passes through a resistance of one ohm for one second.

L - Line Output Converter (LOC)

This device converts a speaker-level output signal into an RCA preamp-level signal by lowering the amount of voltage.

M - Midrange Speaker

A midrange speaker is specifically built to reproduce frequencies that fall in the middle of the audible bandwidth spectrum, which is between 300 and 5,000 Hz.

N - Noise Floor

The measure of the signal is created from the sum of all unwanted signals and noise sources. In this case, noise is defined as any signal other than audio outputs.

O - Octave

An octave is either halving or doubling a particular frequency. For instance, 40 Hz is an octave higher than 20 Hz.

P – Peak Power

Peak power is the maximum amount of power that a speaker can maintain for a very short time. Although peak power is something often advertised with many speakers, it’s best to base your selection on RMS power rating.

Q - Q

The ratio of resistance to reactance in a parallel circuit, or the ratio of reactance to resistance in a series circuit.

R – RMS Power

This is the amount of continuous power that your speaker will put out, which is measured in watts. The higher the RMS, the louder you can expect your music to sound upon playback.

S - Subwoofer

A subwoofer is a speaker that is specifically made to produce only the lower end frequencies of your music, or bass, as we mentioned earlier. Its typical frequency range is around 20 – 200 Hz.

T - Tweeter

A tweeter (aka treble speaker) is a small speaker that’s solely intended to produce high-pitched audio frequencies, which traditionally fall in the 5 kHZ to 20 kHz range.

U - Unloading

The tendency of an enclosure to produce no spring or pressure on the woofer.

V – Voice Control

In the wake of Bluetooth and Apple CarPlay/Android Auto, many products now feature voice control as a way of issuing commands.

W - Woofer

A woofer is a loudspeaker that is going to handle all the low and midrange frequencies of your audio playback. Its frequency range is around 50 - 1000 Hz.

X - Xmax

This is the distance a speaker can move while keeping a consistent number of voice coil windings inside the magnetic gap of the speaker.