What is the difference between a car stereo, a head unit, and a receiver?

 

There are a number of names for car stereos: head unit, tuner, controller or receiver. The term car stereo is a broad term, but the others have more specific meanings. However, many times these names are used interchangeably, which creates confusion and can be incorrect.

• Car stereo is a generic term that can mean the in-dash unit or the whole audio system.

• Controllers are head units that lack an AM/FM tuner.

• Tuners are head units without built-in amplification.

• Receivers are head units with built-in amplification (for example, 4 channels x 50 watts).

• Head unit is a universal name for any in-dash stereo, including tuners, controllers, and receivers.

While in-dash factory or OEM (Original Equipment Manufacturer) stereos vary widely, most aftermarket head units are receivers with built-in amplification. Thus, for simplicity and consistency with manufacturer product descriptions, the Car Electronics Resource Center refers to in-dash factory head units as factory stereos and in-dash aftermarket head units as receivers.

 

Can my existing car audio system be upgraded?

 

Definitely! There are ways to upgrade almost any car audio system. Some upgrades are simple and others are more complex. The options available to you depend on the inputs/outputs and features that are available with your current stereo.

• If your factory stereo does not have iPod connectivity or Satellite Radio and you want those features, consider adding an iPod or Satellite Radio input adapter to expand your media choices, without replacing the factory stereo.

• If your factory stereo has a weak maximum volume limit and you want to overcome road and wind noises, consider adding an amplifier to increase musical clarity at higher volumes.

• If your factory stereo does play video content and you want to entertain rear seat passengers, consider adding rear seat video system such as pre-fabricated headrest monitors or an overhead ‘flip-down’ screen with DVD player built in.

• If your factory audio system lacks the quality of sound you desire and you want to improve it, consider upgrading to coaxial or component speakers or adding a subwoofer along with amplifiers.

If I want to upgrade my car audio system, do I have to remove my factory stereo?

 

Replacing the factory stereo is not always necessary. Many factory stereos have CD or DVD capability as well as AUX inputs to expand music and media options. Stereos that lack AUX input, navigation, or iPod controls are ideal candidates for replacement with an aftermarket receiver. Upgrading to a receiver will allow you to take advantage of new technology and features.

If I want to upgrade my factory stereo to an aftermarket receiver, how do I know if it will fit and function properly in my vehicle?

 

to research the size of receiver that fits your vehicle

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Amazon.com Car Electronics Fit-Finder

Sonic Electronic car audio finder

Crutchfield fit guide

Metra fit guide

 

If I upgrade my factory stereo to an aftermarket receiver, can I still maintain the look of my car’s dash?

 

Definitely! Receivers can look ‘factory-installed’ with the use of dash panel replacement kits and specific harnessess. These kits/harnesses are designed for the specific year/make/model of a vehicle and often retain factory features, such as steering wheel controls and safety systems like OnStar.

Can I add Bluetooth or an iPod connection to my existing receiver?

 

Absolutely! If your receiver does not include iPod or Bluetooth connectivity, there are vehicle-specific wiring harness adapters available to connect universal Bluetooth hands-free kits to almost any vehicle and use the existing speakers in the car.

How do I know if I should add an amplifier?

 

Most factory stereos lack the wattage to provide high quality audio and aftermarket receivers average only 12 watts RMS of built-in amplification. If your speaker RMS power handling is higher than 12 watts or the audio system lacks enough clarity at high volume, consider adding an amplifier. Always be sure to match amplifier RMS wattage per channel with the speaker’s RMS power handling (i.e. for speakers with 50 watts RMS of power handling, provide about 50 watts of amplifier power to each speaker). An amplifier is also necessary when adding an unpowered subwoofer (a subwoofer without built-in amplification). Similar to speakers, match amplifier RMS wattage per channel with the subwoofer’s RMS power handling.

What is the difference between RMS and peak power ratings?

 

RMS (Root Mean Square) is the electrical equivalent of continuous power. Peak power is a measurement of maximum wattage possible, but peak power cannot be sustained for more than a fraction of a second. Manufacturers use different methods and assumptions when calculating peak power ratings, making it difficult to compare different amplifier models. RMS power, however, is generally rated at a standard level of 1% distortion, which is the threshold for hearing distorted sound. RMS power ratings represent a realistic expectation of performance and allow consumers to compare different amplifier models with relative consistency rather than relying on split second peak power ratings. For these reasons, use RMS rather than peak power when selecting an amplifier.

How do I know how much wattage my upgraded car audio system will need?

 

Receivers typically do not provide the wattage needed to effectively power speakers. Check the RMS per channel wattage (also referred to as power) handling of the speaker(s) or subwoofer(s), then select an amplifier with the same (or slightly more) per channel wattage capability. In general, consider an amplifier with at least 50-100 watts RMS per channel for midrange/tweeter component speakers. Depending on the subwoofer, consider 150-300 watts RMS per channel.

How many channels do I need for my receiver or amplifier?

 

Channels refer to the number of audio outputs a receiver or amplifier supports. One positive and one negative audio output constitutes a channel. Channels and wattage (also referred to as power) specifications are expressed as the number of channels multiplied by watts per channel. For example, a 4-channel x 100 watt amplifier can support four speakers and delivers 100 watts per channel, for a total of 400 watts.

• Receivers – The number of channels should be matched to the number of speakers in the system. Thus, a 4 x 25 watt receiver can power four speakers. This matches the typical configuration of two front speakers and two rear speakers.

• Amplifiers – For amplifiers, the number of channels does not have to match the number of speakers. A mono amplifier can provide a single output channel that drives multiple subwoofers wired in a series or parallel configuration. Conversely, the channels of a 2-channel amplifier can be bridged (or combined) to power a single subwoofer. A 2-channel amplifier can power component speakers with a midrange speaker in the front door and a tweeter in the windshield pillar panel, all separated by a passive crossover. The number of speaker(s) connected to a particular amplifier channel will be different depending on the design, system choices, and the configuration of the equipment.

What does bridging an amplifier mean? When would I want to do this?

 

Bridging an amplifier means combining a pair of channels into a single, more powerful output channel. Bridging channels is a common technique to power a subwoofer when using a 2-channel amplifier. The wattage increase after bridging two channels is at least double the single channel rating, and can be up to four times the single channel rated power at the same load. Similar to the increase in wattage, the current drawn from the vehicle electrical system also doubles in a bridged configuration. Be sure to choose power wires that are rated to handle the higher current levels and select a mounting location that allows for adequate cooling. Always check the amplifier specifications to determine if it is bridgeable and what the power increase will be from bridging for a given configuration.

 

What are the different amplifier classes? What do they mean?

 

Amplifier classes used in car audio include Class A/B, Class D, and Class G/H. The amplifier’s class designates the type of circuit operation it uses. Each class has operational characteristics that meet performance versus cost objectives, including the required current draw from the vehicle electrical system to deliver the rated output power. Class A amplifiers are primarily used in quality home audio systems, but consume too much current for practical use in the car. Most car audio amplifiers are Class A/B or Class D. Newer amplifier designs use Class G/H circuitry with more efficient audio output voltage monitoring than Class A/B or D. Class A/B amplifiers are 60-65% efficient in power conversion. Class D and Class G/H are 70-80% efficient in power conversion. The sound quality comparisons are subjective and often depend on other parts of the audio system, such as the receiver, speakers, and audio signal wiring.

 

.What is a Digital Signal Processor?

 

A Digital Signal Processor (DSP) is a microprocessor that digitally manipulates audio signals rather than through an analog process using resistors, inductors and capacitors. Use of analog audio signal requires analog-to-digital converters (ADC) at the DSP inputs. Digital signal processors that are part of an analog audio signal path must use digital-to-analog converters (DAC) to convert audio signal back to analog form before sending the processed audio signal out to the audio system. Digital Signal Processors often have equalization, time alignment, and crossover functions that provide tweaking capability to the audio system’s sound quality. A DSP is a separate physical device that connects (or integrates) with existing audio system components. DSP technology can also be included as a feature in a receiver.

 

How can I add amplifiers to my existing receiver?

 

Output converters allow for the addition of amplifiers to a receiver. These converters connect directly to the speaker outputs, either at the receiver output or (if equipped) at the speaker wiring of an existing amplifier output, and provide preamp level (RCA) outputs for adding one or more amplifiers. A basic output converter is a Line Output Converter (LOC). More advanced output converter devices are Digital Signal Processor (DSP) based devices that often handle multiple input channels and include other attributes such as equalization, time alignment and digital crossovers.

 

Are all back-up cameras the same?

 

Nope. There are several different types of back-up cameras which accommodate different types of vehicles and installation space.

• Factory-Style Camera – This style is similar in appearance and installation to the cameras that are factory-installed and is intended for cars sold without a factory installed back-up camera. These mount exactly the same as the factory camera. The actual location varies by vehicle application.

• Surface-mount Camera – This style is self-contained with mounting tabs or brackets to attach the camera to the vehicle. It is installed at the top of the hatch (on SUVs and hatchbacks) or under the license plate light housing.

• Flush-Mount Camera – This style is installed into an existing or custom drilled hole allowing the camera to fit “flush” into the vehicle body, rear light housing, or trunk lid.

• License Plate Mount Camera – This style is built into a license plate frame or an attachment to the existing license plate mount.

Do I need to buy a screen with my back-up camera?

 

If you do not have an existing video screen in the vehicle with an available video input, you will need to purchase a stand-alone in-dash or on-dash video/LCD monitor. Many video/DVD receivers have video inputs designed specifically for adding a back-up camera.

Do I need a subscription for satellite radio?

 

Yes. SiriusXM satellite radio service requires a monthly subscription. Once installed, you need to select your service plan and activate SiriusXM service by calling 866-635-2349 or visiting their https://care.siriusxm.com. There are content packages that fit all budgets. For an additional fee, you can add SiriusXM service to your computer, tablet, or Smartphone with the SiriusXM Internet Radio.

What are dash kits and brackets?

 

Dash kits are replacement panels that ensure a clean look and secure installation when replacing or upgrading your in-dash receiver. Mounting brackets are used when the receiver is not a direct fit to the existing dash opening. Dash kits and brackets allow the receiver to fit securely into a Single-DIN or Double-DIN opening and provide a factory-like fit and appearance.

When do I need dash kits and brackets?

 

You should consider purchasing a dash kit when installing an aftermarket Single-DIN or Double-DIN receiver in a vehicle with a radio opening that does not directly accommodate either size without modification. If the existing brackets are not removable, additional mounting brackets may also be required to install the receiver.

 

What are wiring harness adapters?

 

Wiring harness adapters are required to install an aftermarket receiver into a vehicle without cutting the factory wires. Each vehicle make/model has a specific harness adapter for any receiver installation.

When do I need a wiring harness adapter?

 

You should consider purchasing a wiring harness adapter if replacing a factory stereo with an aftermarket receiver.

What is an antenna adapter?

 

Many vehicles have a non-standard AM/FM antenna plug that requires an adapter to mate with the standardized AM/FM input included with most aftermarket receivers.

When do I need an antenna adapter?

 

General Motors vehicles built after January 1986 and most other vehicles built after January 2000 require an antenna adapter.

What is a Steering Wheel Control (SWC) adapter?

 

Many cars have stereo controls, such as volume control, track selection, and mute, built into the steering wheel. A steering wheel control (SWC) adapter translates vehicle steering wheel command signals to a form compatible with an aftermarket receiver.
 

do I need an SWC adapter?

 

An SWC adapter is required to retain steering wheel control functions when installing an aftermarket receiver.

Will my aftermarket products void my vehicle warranty?

 

Absolutely not! Installing and using aftermarket products will not void a vehicle warranty. The Magnuson-Moss Act is a Federal Act that prohibits vehicle manufacturers from voiding warranty expressly because a consumer has installed an aftermarket product.

 

Where are Radar detectors legal?

 

In almost all states! Virginia and Washington, D.C. are the only areas that ban radar detector use in passenger vehicles. Radar detectors are not legal for use in commercial vehicles (vehicles exceeding 10,000 pounds GVW) in the US. Much of Canada also prohibits the use of Radar detectors.

 

Do remote door locking systems secure a vehicle from theft or break in?

 

A door 'lock and unlock' key fob remote is not necessarily a security system. While most new cars include factory-supplied theft deterrent systems, these systems typically offer only basic functions. Aftermarket vehicle security systems provide greater protection including visual deterrents such as a flashing LED and parking lights. Security systems also provide audible deterrents like unique siren sounds or honking the horn. A 2-way security system provides an extended remote control range and allows the security system to report its status and send alerts to the remote. Aftermarket security systems can also control all of the same functions that are available on factory key fob remote controls.

Does a remote car starter also include an aftermarket security system?

Not necessarily. Many full-featured remote starter systems do include security system functionality. If it does not, a security system can be purchased as an add-on to the remote starter