The Sony CDX-GT520 takes the familiar shape of Sony's current line of single-DIN car stereos, having the same basic chassis design as the iPod-playing CDX-GT420IP. In addition to its MP3 and WMA digital audio playback capacities, the star feature of the CDX-GT520 is its ability to play HD Radio, giving drivers access to hundreds of free high-quality audio stations with detailed program and artist information. To play HD Radio via the CDX-GT520, however, drivers must buy and install Sony's optional XT-100HD tuner, a procedure that we found to be far more difficult than it sounds.
With its single open-disc slot, simple hard buttons, and monochrome LCD display, the Sony CDX-GT520 faceplate offers an intuitive interface for playing radio and disc-based sources. In addition to its track-skip buttons on either side of the main control knob, the faceplate includes dedicated buttons for skipping forward and back between folders on MP3 and WMA-encoded discs: a feature that we appreciate in digital-age receivers. We also like the Display hard button to the bottom right of the display, which gives drivers a means of browsing ID3-tag information on MP3 discs, and song, artist, and station information for HD Radio stations.
The layout of the CDX-GT520's bright, white-on-blue display is uncluttered, making it easy to read information at a glance, and we found the simple spectrum analyzer graphic in the top right-hand corner to be a surprisingly informative means of monitoring EQ levels. The front-mounted auxiliary input jack is a nice touch that we have seen in other Sony head units.
With the HD tuner connected, the CDX-GT520 makes HD Radio its own separate source, giving drivers the chance to browse through only those radio stations that broadcast an HD signal. While we like this segmentation of HD Radio, it appears to come at the cost of all other AM and FM analog stations, which are no longer available with the HD tuner connected. On the positive side, HD Radio output is noticeably crisper than standard FM radio, and we do like the track, artist, and channel text information that accompanies most HD broadcasts. One thing we did notice, however, is that, while the CDX-GT520's HD Radio output is clear, its volume range is much lower than that for disc-based audio.
For MP3-, WMA-, and AAC-disc playback, the CDX-GT520 displays up to 10 characters of ID3-tag information for artist, album, and folder, which can be cycled through using the Display button. Using the Shuffle button, drivers can shuffle songs within a specific album; albums on a disc; or all songs in all albums on a disc.
As a standalone device, the CDX-GT520 is a simple, user-friendly in-dash receiver with support for a good range of digital audio sources and some decent audio-customization features. While we like the fact that the stereo is able to act as an HD Radio tuner, we are less than impressed with the necessity for Sony's expensive, clunky XT-100HD module.