All the Bluetooth-enabled car stereos we have reviewed to date have relied on the use of an add-on module, which turned a regular stereo head unit into a hands-free phone interface and a wireless music receiver. Sony's MEX-BT5000 raises the stakes by incorporating built-in Bluetooth capabilities with increased phone functionality, as well as wireless audio support via the advanced A2DP profile (also referred to as Bluetooth 2.0).
Under the hood, the single-DIN Sony MEX-BT5000 is an AM/FM CD receiver using 24-bit digital-to-analog conversion and a built-in S-MOSFET amp to produce a hefty 52Wx4 channels of output. The stereo supports a range of digital audio formats, including MP3, WMA, and ATRAC CD. It is prewired for satellite radio and features a built-in auxiliary input, three pre-outs, and a bus control for connecting a CD changer. It also includes a feature called 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 our experience, the restoration procedure works to a degree, but MP3 discs are still conspicuously less clear than regular CDs. The MEX-BT5000 offers a wide range of preset EQ configurations--ranging from the bass-heavy Xplod setting to the high-end-dominant Space setting to Vocal--enabling listeners to match the tuner output to their choice of input. A Custom function also enabled us to set our own EQ preferences with the aid of a graphical representation for low-, mid-, and high-range output.
The X factor
The MEX-BT5000 announces its membership in the Sony Xplod family of in-car audio offerings thanks to a stylized X on the left-hand side of its faceplate, around which are clustered the head unit's main controls. Most conspicuous among these are a large joystick and a copper-colored Source button shaped like a tie clip. Despite our general aversion to joystick/buttons--which tend to be difficult to control when pushed to make a selection--the MEX-BT5000's four-way joystick is robust enough to enable easy scrolling and feature selection. Even when pushed in at an angle, the joystick resists tipping over to make unwanted directional selections. The placement of the Source button nearest to the driver is a nice touch, but we are at a loss to understand why there is no marked On or Power button and why the controls for making and hanging up phone calls are so small and dislocated (more on this in the hands-free-calling section).
Other controls, including dedicated push buttons for Bluetooth configuration and Menu, and the faceplate's six preset hard buttons are intuitive and easy to operate. We found navigating CDs and MP3 and WMA discs easy and designed to accommodate music selection on the move: to skip through tracks, just push the almighty joystick to the left or right, while up and down cycles through albums. The MEX-BT5000 offers a selection of jazzy background-display animations, which tend to obscure the album, track, and ID3-tag information. We preferred turning the graphics off.
Bluetooth wireless streaming
In preparation for streaming audio files from our Nokia 5300 cell phone to the stereo, it took about three minutes for the MEX-BT5000 to pair with our phone, most of which time was spent waiting for the two devices to recognize each other. To pair a phone to the MEX-BT5000, turn its Bluetooth on and set it to be visible to other devices. After a couple of attempts, our phone found the stereo, which showed up as "Xplod" on the found-devices screen; frustratingly, the MEX-BT5000 had also found our phone, but listed it as "unknown" on the LCD display. With pairing complete, we were instantly able to stream audio files from the phone to the stereo and thence out through our four test-bench speakers. We were also able to play, pause, and skip tracks using either the controls on the phone handset or those on the stereo, although volume control was possible only by twiddling the MEX-BT5000 joystick (phone volume controls are rendered redundant).
On the other hand, track and artist information for streamed audio files were visible only on the phone's display, which was a little annoying, but this is something that will likely be addressed as Bluetooth 2.0 evolves. Sound quality of the streamed audio is what we expected from a technology that is still developing, with intermittent cut-out and a noticeable reduction in clarity in volume compared with CD-based (and BBE MP-restored) digital audio files. One feature that we really liked was the way that streamed audio continues to play while the preparations are being made to make a hands-free call via Bluetooth connection. We were able to get into the phone menu and dial our chosen phone number without cutting the audio stream. Only when we were ready to make the call did the Bluetooth connection switch from music to voice.
Making the call
Hands-free calling via the MEX-BT5000 is also straightforward to set up. Having already paired the phone to wirelessly stream music, we didn't have to do so again for making calls, but the process is much the same if you just want to use the Bluetooth for phoning while driving. To pair up our Bluetooth-enabled Samsung SGH-T619, we navigated through the menu (Settings > Connection > Search), and the head unit took about 30 seconds to find and correctly identify our phone. After allowing access and entering our chosen passcode, we punched the same code into our phone, and we were ready to call. The stereo is a completely autonomous phone interface: we could enter numbers using the joystick, then call out without having to take our phone out of our pocket.
While it can be laborious process to cycle through and select the 10 numerals, it is better than other systems we've seen that require the driver to use a cell phone to initiate outbound calls, which are then transferred to the head unit interface. Another elegant feature of the MEX-BT5000 is its built-in microphone, which obviates the need to wire up an external mic to a car's sun visor. One of our favorite things about the MEX-BT5000 is its versatility for making hands-free calls and its ability to store contact and call-history information. An item menu called Receive PB prepares the MEX-BT5000 for wireless phone book transfer of up to 50 contacts. Alternatively, callers can access six speed-dial entries using the preset button on the front of the faceplate or select numbers from a list of previously dialed or received calls.
Call quality is in the same league as other hands-free units we've seen, with incoming calls sounding good through the car speakers but outgoing calls coming through in slightly muffled, cavernous acoustics usually associated with speakerphones. With all of its terrific functions, the principal drawback of the MEX-BT5000 comes in the form of its start- and end-call buttons. Rather than having one large, conspicuous button for both functions in the vein of most OEM Bluetooth interfaces, the MEX-BT5000 presents drivers with one slim button hidden from the driver's view by the joystick to make outgoing calls, and another button (which doubles as the control to turn the entire stereo off) for hanging up. Pressing the start-call button while the call is underway results in the stereo passing the call back to the cell phone handset. Owners of the unit will probably get used to this strange arrangement, but we would have liked a more intuitive design.
Despite its few functionality quirks, however, the MEX-BT5000 is an attractive combination of advanced Bluetooth communication and entertainment features and high-quality digital audio playback.