Sony MEX-BT2500

The MEX-BT2500 is Sony's second Bluetooth-enabled in-car stereo, following in the footsteps of the MEX-BT5000, which we reviewed last year. Like the BT-5000, the MEX-BT2500 features Bluetooth hands-free calling and audio streaming capabilities, however, its plainer display, and more-limited audio processing and output features make it the entry-level model for those looking for a wireless communications and entertainment device.

Design
The Sony MEX-BT2500 features a simple, single-DIN-size faceplate with an open CD slot and a standard arrangement of hard buttons along the bottom of the bezel. To the left of the unit's white-on-black monochrome display, the rotary volume knob doubles as a start/end call control, while six hard buttons surrounding it constitute the main control selections. While it is a member of Sony's Xplod in-car audio range, the MEX-BT2500 does not have the prominent X-themed styling of its higher-end MEX-BT5000 sibling, and instead features a tasteful blue backlighting for the volume dial and the Source and Mode buttons.

The MEX-BT2500's intuitive design leads to straightforward music and call control when on the road. Pressing the Source button scrolls through the system's major functions (CD, auxiliary input, Bluetooth audio, Bluetooth phone, tuner), while the Mode button enables drivers to configure the display to show different categories of ID3 tag information when playing back digital audio discs.

Bluetooth calling
As the Bluetooth functionality is the main selling point of the MEX-BT2500, ease of pairing and strength of Bluetooth connection are key factors in its performance. We had no difficulty in pairing our Nokia 5700 music phone to the system. To pair a phone, users have to set the MEX-BT2500 to Off mode with the digital clock showing, then hold down the Bluetooth button until the Bluetooth logo starts to flash on the stereo's LCD display. The rest of the pairing procedure is conducted using the phone itself by searching for the stereo. The system can be paired with as many as five cell phones simultaneously. One of the limitations of the MEX-BT2500's hands-free calling interface is that it cannot be used to place outgoing calls other than redialing a connected cell phone's last number. The principle purpose of the system, therefore, is to accept incoming calls. When a connected cell phone is called, the MEX-BT2500 sounds a trilling ringtone through the car's speakers.

To answer the call, the driver simply pushes in the large volume knob, the same action used to end a call. We like the fact that there is a single, large interface for accepting and hanging up calls--one of our criticisms of the MEX-BT5000 was the dislocation of the start and end call buttons, and their relatively small size. For incoming calls, the sound quality thorough the car's speakers is clear and intelligible; however, the same is not true from the other end of the line. The MEX-BT2500 makes use of a built-in microphone, and, while we like the convenience and design economy that this affords, its performance leaves a lot to be desired: call quality from the other end of the line is distant, intermittent, and echoey, and in our test, we found ourselves having to ask the person on the other end of the line to repeat what was said. On another mildly negative note, there is no way to transfer one's cell phone contact book to the MEX-BT2500. Although for a system this price, that is not such a surprise.

Audio
We like the fact that you have only to pair a phone once to the MEX-BT2500 to be able to receive hands-free calls and to stream audio. As the two functions involve different Bluetooth protocols, some car stereos require two separate pairing procedures. With a Bluetooth audio device paired, the MEX-BT2500 is ready to receive streamed audio via A2DP. The source music player/phone must be used to start playback of a track or a playlist, but once started, the controls on the stereo can be used to skip forward and back, pause and restart tracks, and control volume level.

Unlike the system in the higher-end MEX-BT5000, users can also control audio volume for tracks playing through the car's speakers by using the volume control on the phone/music player itself. During Bluetooth audio playback, no track information is transferred to the stereo's display, so drivers will have to either refer to the phone display for track information or select tunes by ear when on the road.

The MEX-BT2500 can play regular Red Book CDs as well as MP3/WMA digital audio discs. For the latter, the system's bright LCD display shows eight ID3 tag characters, which automatically scroll across the screen. In a nice design feature, drivers can switch between different tag categories (such as album, track, or song title) by pressing the DSPL button.

We also like the front-mounted auxiliary input jack, which can be used to play audio from portable non-A2DP-enabled music players such as iPods. Audio-tweaking functions on the MEX-BT2500 are limited to a number of preset EQ configurations and a custom setting that enables the driver to set high and low outputs. Like the MEX-BT5000, the MEX-BT2500 kicks out 52W (max) through four channels via a digital-to-analog converter. However, the entry-level unit lacks a number of the MEX-BT5000's more advanced audio capabilities, such as its EQ3 parametric leveler, and its BBE MP signal processing, which restores some of the sound quality lost through the compression of digital audio files by reamplifying acoustic details or "harmonics" that were reduced in the compression process.

In sum
The Sony MEX-BT2500 is a value-for-money car stereo for those looking for decent audio features and sound quality with Bluetooth calling and audio streaming capabilities. If you can live with the muddy call quality that the system's built-in microphone delivers, then the stylish and intuitive MEX-BT2500 is a good entry-level option.