For almost as long as cars have been driven, people have wanted to listen to music while on the go. Early systems often struggled with skipping records and cassettes but eventually manufacturers realized that sound quality was important and many vehicles now come with premium stereo options.
To create the sound you hear while driving, the audio signal needs to pass through the speakers and vibrate them. This process happens thanks to amplifiers, which boost the low-level signals from the head unit.
Head Unit
The head unit is at the center of a car audio system. It is also known as the radio, stereo or CD player (although those are only two of the many possible names for this component). It produces an electronic signal that gets sent to the amplifier in order to help create sound. The amplifier then sends power to the speakers, turning that signal into vibrations.
These vibrations then travel through the air in the vehicle and create the sound that you hear when listening to music or talking on the phone. The head unit also includes controls that allow you to play, stop and skip tracks or radio stations. Some also have a display screen that shows song information or lets you view your vehicle’s odometer or other data.
In recent years, the options and features available on head units have expanded greatly. Some come with built-in satellite radio, auxiliary or USB inputs that let you connect an external device and even Bluetooth audio for hands-free calling and music streaming. Many also feature voice commands that allow you to operate the system by simply using your spoken commands.
Some newer head units also feature video functionality, which allows you to play DVDs or Blu-ray discs or digitally stream video data to a compatible display screen. They can also play back what is called “factory-preprocessed” or “factory-equalized” sound files that are digitally processed to mimic the original quality of the sound in your car’s speakers.
The preamp is the first part of a car audio system that is responsible for taking the various raw signals from a head unit and sending them to the amplifier. This process is what gives the amplifier its rated power, which is usually noted on the head unit with the built-in amp or the label of a stand-alone amplifier.
The speaker, the last of the three primary components, is the most important for producing great sound quality in your car’s audio system. This is because the best sounding audio system in the world will still have poor quality if the speakers are subpar. Good quality speakers, on the other hand, can take even a basic head unit and amplifier and turn them into something that is truly impressive.
Amplifier
The amplifier is the heart of a car audio system. It boosts the inaudible line-level signal from the head unit so it’s strong enough to move a speaker cone back and forth, producing sound. As a result of amplifying this signal, the amplifier generates a lot of heat, so it’s important to design it so it doesn’t overheat and break. Amps are usually larger than the head units they’re built into because of this.
In addition to boosting the line-level signal, an amplifier has other functions, including voltage regulation and power storage. It can be a challenge to find the right balance of performance, size and cost in an automotive amplifier, especially since many factors affect its ability to produce clean, high-quality sound.
As a general rule, an amplifier’s output stage will become audibly distorted at about three-quarters of its maximum volume. This is because most factory stereos don’t have enough output power to overcome road noise without sounding shrill and annoying. That’s why most people invest in a separate, high-quality amplifier when upgrading their car audio systems.
Amplifiers need a steady supply of electricity to work, and this is where a vehicle’s battery comes in. The positive input of the amplifier is wired to the positive terminal of the battery, while its negative input is connected to a ground location within the vehicle.
A good installation shop will use a battery isolator switch to ensure that the amplifier only receives power when the ignition is switched on. This prevents the amplifier from draining the battery during long periods of idling, which can cause it to overheat and short circuit.
Amps also need to be configured properly to provide optimum output for each set of speakers in the system. A reputable installer will set the gain controls of an amplifier to match the target impedance of each speaker, using test equipment to determine this. This eliminates the guesswork that’s often involved when people try to set their own gains on amplifiers they purchased online. There are plenty of YouTube videos that purport to teach people how to set their own gains, but these typically contain bad information and old wives’ tales.
Speakers
Probably the most important part of any car audio system is its speakers. They take the electrical signals from the head unit and turn them into mechanical movements – air vibrating against a speaker cone to create sound waves that we can hear.
Inside the speaker is a flexible cone-shaped diaphragm, called a voice coil. The voice coil is surrounded by a magnetic field. When the voice coil moves back and forth, it creates vibrations in the diaphragm that create compressions of the air. This creates the sound you hear when you jam to your favorite tunes.
The louder the volume you play, the more air is compressed and the more sound you hear. That’s why it’s important to have a quality amplifier with plenty of power – your speakers are only as good as the amplifier that drives them.
In fact, many factory-installed systems have sub-par amps and speakers – replacing these with higher-quality components can make a significant difference in the quality of your music.
If you’re looking to make even more of a difference, we offer premium aftermarket speakers for every vehicle we carry that deliver amazing sound that can be heard and enjoyed from any seat in the car.
There are several different kinds of speakers to choose from based on the frequency range they reproduce. Woofers produce low frequencies, midrange speakers reproduce the middle audio spectrum and tweeters provide the high-frequency sounds like cymbals and high-hats that give depth and detail to your songs. Many speakers combine the duties of woofers, midrange and tweeters into a single “full range” speaker to save space and cost.
To get the best sound from your speakers, you need to consider things like speaker path lengths. It’s crucial to keep the distance from the speaker to your ear (also called the acoustic sweet spot) as close to identical as possible across all drivers to avoid distortion in the sound. It’s also critical to match the size and type of speakers in a stereo to ensure they work together as well as they can to reproduce your music.
Wiring
In order to work, a car audio system must have a power supply. This is often a vehicle’s battery. It must also have a ground wire that connects to the chassis of your car. A good quality ground wire will reduce noise and vibration that can damage components. It should be thick enough to handle the current that flows through it.
The power amp takes the low-level audio signal sent by the head unit and increases it dramatically. This boosted signal is what moves the speakers and creates the music you jam to when driving down the road. The speakers convert this electrical movement into mechanical motion by vibrating the paper cones to produce specific notes in a particular frequency range.
During the car audio installation process there are many potential errors that can be made. These can be due to a lack of knowledge or experience, purchasing the wrong device, not knowing your car’s specifications and so on. However, one of the most common mistakes is incorrect wiring. There can be hundreds of watts of power flowing through a single wire at any time, so it is very important to use high-quality cables and connectors.
It is also important to follow the instructions that come with your new equipment. Using a proper crimper (or a punch and hammer) when running wires is crucial to getting a solid connection. It is best to use a hydraulic crimper, but you can also find a variety of other types of tools and accessories at your local auto parts store to help with the install. These include:
It is also important to pay attention to the gauge (thickness) of your speaker wires and power wires. Thicker wires generally provide a higher level of performance and durability, especially in the sometimes harsh environments inside your car. The wires should be insulated to reduce noise and to protect them from moisture. Finally, a good quality ground cable is vital to ensure that the electrical current in your car audio system doesn’t flow back through its engine and cause fires or other problems.