Car stereos are the audio systems set in the dashboards of an automobile. Most typical car stereos set in the dashboards are integrated types of stereo systems in which the main body of each stereo is integrated with the front panel into a single body. Many car stereo systems (including vehicle computer systems and vehicle entertainment systems) include multiple bands, such as AM, FM1, FM2, and CD. The selected band represents the operating state of the car stereo. After selecting a particular band, the user selects a preset button to select between radio stations (or CD in a CD Changer) or a tuning buttons to tune a particular radio station. The basic unit of a vehicle audio system is a radio augmented by other program sources such as a cassette tape player and/or a compact disc (CD) changer or player which is processed by a portion of the radio circuits. Radios in an automotive vehicle are provided with a receiver which is mounted in the dashboard of the automotive vehicle. The visible surface of the car radio, which then matches the remainder of the dashboard, is used to receive the control elements and display elements, such as control knobs, display panels, dials, and indicators. In obtaining the best audio fidelity possible in radios and other sound systems, speakers play a crucial role, and several factors govern how well a speaker will perform. Generally, speakers for automotive audio systems can be installed at various locations in the vehicle compartment. An audio speaker is a device that receives a signal and produces sound. The signal received by a speaker typically is an electric signal produced by an audio amplifier. The speaker receives the amplifier signal and produces vibrations which produce sound. High power audio amplifiers are frequently added to an entertainment system in a car to amplify the audio output from a radio mounted in the vehicle. These high-power amplifiers are usually housed in a chassis or enclosure different from the radio, and they are frequently mounted in a location that is not near the radio. In recent years automobile audio manufacturers have improved auto stereo entertainment and provide a diverse line of digital audio equipment. Many car stereo systems are equipped with devices for playing digitally recorded media. Such devices may include compact disc (CD) players, digital video disc (DVD) players, and mini disc players. Widely accepted technologies that may be implemented within an automobile include, cellular/global system for mobile communications, global positioning system (GPS), and radio data broadcast (RDB). These devices allow a driver to navigate, receive real-time traffic information and weather forecasts, access databases of personalized information, and place and receive telephone calls from an automobile. Vehicle computer systems provide the opportunity to add new features and functions to existing car stereo systems. For example, a vehicle computer system may provide navigational functions in addition to conventional car stereo functions. With the use of digital technology in sound systems, a digital signal processor (DSP) in the radio processes the incoming audio signal to achieve bass and treble control and room effect simulations, and outputs audio signals to the speakers which are distributed throughout the vehicle.

Generally, a car audio device comprises a drive mechanism for carrying out recording/playback on and from a medium, a front panel provided with an opening for insertion of the medium and a plurality of control keys, a chassis for supporting the drive mechanism and the front panel, a main board attached to the chassis. Various circuit components, including a microcontroller, are mounted on the main board. A tone control unit of vehicle audio system for controlling the tone quality of the input audio signal performs equalizer control and high/low tone control in accordance with an instruction given by the audio control unit. A volume control unit for controlling the volume performs volume control, loudness control, mute on/off control, and the like in accordance with an instruction given by the audio control unit. The audio volume of the radio is normally adjusted by means of a volume control resistor pot which is connected to the volume control input to a volume control preamplifier within the receiver. The volume control resistor pot is normally adjusted by manual manipulation of a rotatable dial. The dial is rotated in one direction to increase the volume of audio output from the speakers, and counter rotated in an opposite direction to reduce the volume of the audio output of the radio speakers. An amplifier amplifies the input audio signal. A speaker emits sound into the interior of a vehicle. An operating unit performs operations such as power on/off, source switching, tone characteristics setting, volume up/down, AM/FM band switching, broadcasting station channel selection, play/stop/pause of the CD player, fast-forward/reversing, and tune-forwarding of the CD player. Audio systems reproducing sounds are devised to convert low frequency band component signals extracted from audio signals to mechanical vibrations to have a listener directly and bodily sense the vibrations, in addition to producing acoustic effects by an acoustic transducer such as a speaker which transmits music sounds through air propagation. Some vehicles have controls for audio components on the front of the steering wheel. This location allows the driver to keep a hand close to the steering wheel, and requires minimal visual searching.