Yamaha NX-B02 Bluetooth Speakers (black)

Last year, Yamaha created a small portable speaker called the NX-A01 that delivered gutsy sound in a space no larger than a Rubik's cube. It had only two considerable drawbacks: it had to be plugged in; and the US model lacked the Bluetooth audio capability of the version selling in Japan. Well, someone at Yamaha must have heard us, because their NX-B02 ($199) is an impressive evolution of the NX-A01--adding Bluetooth and battery-powered portability, into a taller, more elegant design.

Design
Unlike its squat, cubic ancestor, the Yamaha NX-B02 reminds us of a miniature, modern office tower. Available in black, white, and red, each side of the Yamaha NX-B02 measures 3.25 inches wide, giving it a perfectly square footprint that extends 6.75 inches high. Yamaha's biggest design achievement with the Yamaha NX-B02 isn't what was added; it's what was taken away. One need only to look at the legions of flat panel TV owners running AV cables through their walls, to get a sense of how much people hate the sight of cables. Jumping on this cable-free bandwagon, the Yamaha NX-B02 takes advantage of battery power (four AA) and Bluetooth wireless audio, in addition to its wired power and audio connections.

Features
The NX-B02's features are as streamlined as its design. The four buttons at the top of the NX-B02 control power, volume, and Bluetooth activation. The left and right sides of the NX-B02 each conceal a single 1.75-inch titanium cone driver and a bass port design from the NX-A01. On the back of the NX-B02 you'll find discreet connections for the power supply and 3.5mm stereo input, both of which are unnecessary should you choose to run the NX-B02 using batteries and Bluetooth.

Performance
The NX-B02 may be twice the size of the NX-A01, but don't expect twice the sound. We're happy to see that the NX-B02 is less prone to distortion at full volume than its predecessor, but sonically, the NX-B02 is only incrementally better than the NX-A01.

Realistically, the NX-B02 isn't meant to go toe-to-toe with a home stereo or full-size boombox. Its compact size and attractive design makes the NX-B02 an excellent choice for an otherwise quiet space such as a bedroom, kitchen, or office. That said, the Yamaha NX-B02's is capable of getting loud enough to shout over. In fact, we found that the NX-B02 presented the best balance of bass and treble at medium-to-high volume, tending toward a thin, tinny quality when played quietly.

The top of the Yamaha NX-B02 features four buttons that control volume, power, and Bluetooth activation. An LED light in the center glows green when power is on, and blue when Bluetooth is on.

Connecting to the Yamaha NX-B02 over Bluetooth is a cinch. To put the speaker into Bluetooth discovery mode, you just hold down the Bluetooth button on the top of the NX-B02 until the normally green LED light below the button begins flashing blue. Once activated, we had no problem getting our laptop and cell phone to recognize and pair with the NX-B02.

Bearing in mind that the Yamaha NX-B02 is not intended to be a platform for critical listening, we found that the audio performance using Bluetooth to be basically as good as plugging an audio source in directly. While in Bluetooth mode, we did notice a faint, high-pitched squeal in the background that was easily drowned out by the music, but could drive you batty over prolonged listening. During testing we found that the Yamaha NX-B02's Bluetooth wireless range could go up to 30 feet without hiccups, as long as there were no solid walls between the speaker and the audio source. We couldn't get the Yamaha NX-B02 to transmit between rooms, however, which makes it a poor solution for someone looking for a wireless speaker system comparable with the Griffin Evolve.

While wireless Bluetooth audio is an undoubtedly great feature to have, the Yamaha NX-B02's portability as a battery-powered speaker is arguably more useful. With a rated battery life of 4 hours and a size no bigger than a super burrito, the mind reels with possibilities. Match the NX-B02 with an ultraportable MP3 player, such as an iPod Shuffle or SanDisk Sansa Clip, and you've got a little, mobile discotheque that can fit in a picnic basket, suitcase, bookshelf, or nightstand.