Spark

Radio/Audio System Description and Operation

Each item in the list below represents topics covered in detail below.

Fixed Mast Aerial

The fixed mast aerial can withstand most car washes without being damaged. If the mast should ever become slightly bent, straighten it out by hand. If the mast is badly bent, replace it.

Radio Signal

The radio signal is sent from a broadcast station and is then received by an aerial. The strength of the signal received depends on the following:

AM Reception

The AM band has a lower frequency range than the FM band. These longer wavelengths:

The AM frequencies have longer range due to the ground wave. The ground wave follows the curvature of the earth and is effected by its conductivity. Greater conductivity equates to less signal loss thus transmission over water is better than over land. The AM band has a range of 80-320 km (50-200 miles).

FM Reception

The shorter wavelengths of the higher frequency FM band:

Broadcasts in the FM band are limited to line of sight reception which is typically 40 km (25 miles). Even when out of a direct line of sight, the signal may be reflected into areas that would be in a shadow otherwise. Factors which affect the line of sight include:

Speakers turn electrical energy into mechanical energy to move air, using a permanent magnet and an electromagnet. The electromagnet is energised when the radio or amplifier (if equipped) delivers current to the voice coil on the speaker. The voice coil will form a north and south pole that will cause the voice coil and the speaker cone to move in relation to the permanent magnet. The current delivered to the speaker is rapidly changing alternating current (A/C). This causes the speaker cone to move in two directions producing sound. When the speaker is at rest, such as when the volume at a minimum value, the voltage applied to each side of the speaker is ½ ignition system voltage. This way, the speaker cone can be moved in either direction.

The Compact Disc (CD) player provides exceptional clarity and provides low background noise through digital reproduction. A selectable audio compression circuit processes the audio signal. This processed audio signal brings quiet and loud music passages into a more desirable listening range. This is especially useful in the automotive environment. When using compression, a demanding recording can be listened to without continually adjusting the volume.

The automotive environment can be a difficult one for sophisticated electronics. The CD player design takes into account many of the problems seen in automobiles. The player is designed to protect its optics from humidity and from excessive heat by automatically shutting down and ejecting the disc or displaying ERR. A special nylon filter across the disc opening protects the disc mechanism's optics from interference caused by moisture, dust and sunlight.

The loading system gently draws the disc into the mechanism. An ejected disc extends out almost halfway allowing the user to easily manage the disc. The loading system prevents damage to the disc if insertion of a second disc is attempted.

The use of a laser beam to read digital information means the disc will rarely wear out. There is no physical contact with the disc. An occasional skip due to rough roads will not damage the disc.

Some audio functions are available using the steering wheel controls. The steering wheel controls duplicate the function of the primary controls available on the radio.

For additional information on steering wheel controls, refer to Steering Wheel Controls Description and Operation .

A remote 3.5 mm auxiliary stereo jack and USB connector allows playback of audio signals from remote devices (e.g. laptop computer, iPod®, MP3 player, etc.). The radio detects the presence or absence of an audio mini-plug through the Aux Jack Detect input. When the audio mini-plug is inserted in the Aux Detect Switch the mechanical switch closes. When removed the switch is open.

This is not an audio output; do not plug a headphone set into the front auxiliary input jack.

The USB connector uses the USB standards, 1.1 and 2.0. This type of connector supports rates for low speed (1.5 Mb/s), full speed (12 Mb/s), and high speed (480 Mb/s).

USB Supported Devices:

Depending on the USB mass storage device, some devices may not be recognised. The HUB device is not supported. An iPod® can be controlled using the radio buttons and knobs and display the iPod® song information on the radio display. A special iPod® connection cable is needed. This feature supports the following iPod® models:

For proper operation, make sure the iPod® has the latest firmware from Apple®. The iPod® firmware can be updated using the latest iTunes application. See apple.com/itunes. To connect and control the iPod®, connect one end of the specially purchased iPod® connection cable to the iPod® dock connector. Connect the other end to both the USB port and the auxiliary input jack. If the vehicle is on and the USB connection is present, a GM logo appears on the iPod®. The iPod® music displays on the radio display and begins playing through the vehicle radio system. A standard iPod® USB cable, like the one that came with the iPod®, cannot be used to connect an iPod® to the vehicle. The iPod® connection cable that was purchased with the vehicle or that was made available from the dealer must be used in order for this feature to work.