Discs and other digital-media storage
Like in-car radio, disc-based audio has been given a new lease on life thanks to new digital formats. Compressed audio codecs such as MP3, WMA, and AAC give drivers the ability to rip multiple albums onto a single disc, eliminating the need to carry stacks of CDs on the road. Nearly every car stereo that leaves the factory today comes with the ability to play MP3 and WMA-encoded discs; some also feature the ability to play AAC files for music bought on iTunes and burned to disc.
An intuitive interface for navigating digital-audio discs is essential.
With the increased number of tracks on a single disc comes the necessity for an improved means of navigating songs and albums: it is not too much trouble to skip back and forward through 15 songs on a regular CD, but to find the specific track out of hundreds of MP3s on a disc is a lot more difficult.
In CNET's review process, ease of navigating disc-based digital audio is one of the most important factors when considering the merits of a stereo. Many single-DIN systems feature only a single-line, monochrome LCD display, showing no more than eight or ten characters for song title, artist name, and other information. Using such a basic readout to find your way through a maze of folders (directories) and tracks (files) can be difficult. Some systems index all the songs on a disc in seconds, enabling users to search for songs by artist or track name without interrupting the current song.
Stereos such as the Dual XDMA6700, with its scattered audio control buttons, are far less helpful.
If you're planning to play lots of MP3 or WMA-encoded discs, check out the interface for skipping between folders and files and the amount of ID3 tags that can be shown on the stereo's display.
USB and SD cards
The Clarion DFZ675MC features an SD card slot on its faceplate.
Some stereos, such as the Blaupunkt SD48 and the Jensen VM9512, come with integrated SD card readers. For those who want to play SD card files through USB-enabled car stereos, adapters are available.
Bluetooth
Another option for transferring audio to your car stereo is by a Bluetooth radio connection, which can be used to stream music from portable audio players or cell phones with the advanced audio distribution profile (A2DP), often called Bluetooth audio. Some stereos also include the more sophisticated audio/video remote control profile AVRCP, which lets drivers play, pause, and search for files on a Bluetooth-connected device by using the stereo faceplate controls.
Sony's Pioneer DEH-P9800BT.
