Bose products may have their detractors in audiophile circles, but there are many things the company does right, and some the company does brilliantly. The original Bose SoundLink Bluetooth Mobile Speaker is the perfect example of the latter. It's the compact, sounds excellent, and streams stereo Bluetooth audio reliably. The SoundLink Bluetooth Mobile Speaker II ($299.95 direct) is an evolution of the first version, and contains just enough improvements to keep it at the top of the heap for portable wireless Bluetooth speakers—including retaining its Editors' Choice award.

Design, Covers, and Setup
At first glance, it's easy to dismiss the SoundLink Bluetooth Mobile II($214.99 at Amazon) as a minor update, but there's more going on underneath the surface than it appears. As before, the SoundLink II's nylon and leather covers denote the two trim levels. For $299.95, you can get a black-trimmed SoundLink II with a dark gray nylon cover; a chrome-trimmed premium version comes with a dark brown leather cover for $349.95. You can also buy accessory covers in red or blue nylon for $39.95 each, or in black or tan leather for $59.95 each. All of the covers are of a new bi-fold design that doubles as the stand (when opened) and the power switch (when closed), which evokes the Apple iPad with its Smart Cover.

Otherwise, externally, the SoundLink II remains the same. It measures a svelte 5.1 by 9.6 by 1.9 inches (HWD) and weighs 2.9 pounds. It's certainly portable in that it's lighter than most full-size iPod speaker docks, and with the attached cover it folds up nicely. However, it's not as small or light as something like, say, the Beats by Dre Pill; just keep in mind that everyone's definition of "portable" is different.

A battery indicator light at the top of the front panel lets you know the unit's status when you plug it in, while a companion Bluetooth icon pulses in pairing mode, stays solid when connected, and flashes when it can't find any nearby paired Bluetooth devices. The top edge features a row of oversized buttons: Power, Aux, Bluetooth, Mute, and Volume. The back panel, as before, includes a DC power in jack, a micro USB port labeled "service," and a 3.5mm auxiliary input. The DC jack is a bit of a disappointment, because it means you'll need to take the included AC adapter with you everywhere; some other portable Bluetooth speakers use micro USB, which makes it easier to charge multiple devices with a single cable. The built-in rechargeable battery lasts for eight hours of moderate-level listening, and takes three hours to fully charge with the AC adapter.

Pairing with the SoundLink II is simple, and it remembers the last six devices you connected with. I had no problem pairing the SoundLink II with an iPhone 5, upon which I tested the unit with a series of locally stored tracks in various music genres. There's no multi-point support, so you can't leave two devices connected simultaneously and stream from either one; still, it's simple to just power one off and power up the other before cueing up your music.

Performance and Conclusions
Underneath the speaker grille, the SoundLink II features new neodymium drivers and revised digital signal processing circuitry. That's in addition to the original model's dual-opposing passive radiators. The SoundLink II sounds robust considering its tiny size; it puts out a lot of sound with a smooth, even timbre. That said, it's not for audiophiles; there's a lot of digital signal processing going on underneath the hood to prevent distortion and project so much output, and this has a tendency to make things sound nice, but not natural.

When compared with the original SoundLink, the improvement is small, but noticeable. On our standard bass test track from The Knife, "Silent Shout," the new model doesn't distort at all when playing back the introductory electronic synth bass, which is the same as before. But the kick drum is ever so slightly punchier, with a short "boom" tail, on the new model; that's not as good as some larger speakers we've tested, but it's a bit more than you get with the original model, which barely registered in that frequency range.

With other test tracks, the sound was much closer between the two models. Muse's "The Resistance" sounded a bit crisper and less muddy with the SoundLink II, thanks to a slightly enhanced upper midrange presence and a smoother, airier-sounding high range. The same goes for Bill Callahan's "Drover;" his robust baritone sounded clear and full over the acoustic guitar on both models, although you get a slightly more realistic sense of the strings from the new model. One gripe with the older model remains: Sometimes the beginning of a song gets clipped off, either when cueing it up for the first time or when skipping between tracks, thanks to a delay in when the Bluetooth wireless protocol reconnects.

None of the sonic differences are dramatic, or even that noticeable at first listen; if you have the original SoundLink, there's no need to upgrade. But the modest revisions are enough to keep the SoundLink II in the lead as our favorite high-end portable stereo Bluetooth speaker. The Jawbone Big Jambox doesn't sound quite as crisp or detailed, but it's a solid option in its own right and worth consideration, thanks to its long 15-hour battery life, and ability to work as a speakerphone. If you want a low-cost Bluetooth speaker option that's exceptionally portable, have a look at the budget Editors' Choice Logitech UE Mobile Boombox($299.00 at Amazon), although that model doesn't begin to approach the SoundLink II's bass response or overall output level.

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