Altogether, the SBD7500 is a lightweight (9.6 ounces) and compact speaker measuring 4.3 inches tall by 12.2 inches wide by 1.6 inches thick. Fitting the speaker into a backpack or carry-on bag shouldn't prove a problem, but Philips provides a fitted neoprene bag just in case you want to take it solo.
Featurewise, the Philips team kept things simple with the SBD7500--maybe too simple. Compared with similar speakers from Altec Lansing and Logitech, the SBD7500 doesn't offer extras such as FM radio, remote control, or Bluetooth compatibility. Aside from a switch that engages a subtle bass boost feature, the SBD7500 is a really just a straightforward, plug-and-play iPod speaker. Compatibility with the iPhone, as well as shielding against mobile phone interference, are a nice bonus.
The SBD7500 isn't meant to be an audio centerpiece. Ultimately this is the kind of compact, utility-minded speaker you pick up for an office, kitchen, garage, or spare bedroom. Fortunately, with the option to power the SBD7500 from four AA batteries, it's easy to take this speaker from room to room to suit your needs. One set of alkaline batteries should provide about 8 hours of playback at a reasonable volume.
Sonically, the SBD7500 is about as middle-of-the-road as its design, but it packs an impressive amount of bass for its size. Side-by-side with the Altec Lansing inMotion Classic and, the Philips SBD7500 couldn't quite match the power, sound stage, or crisp fidelity of either system but did a better job delivering the kind of thumping low-end most compact systems lack. A few techno tracks from Matthew Dear played at full volume actually had the speaker rattling on the table from the abundance of bass, but we doubt most users will drive the speaker that hard (or listen to techno, for that matter). Fiddling with the integrated bass boost feature offers some extra low-end punch, but the effect was so subtle that we kept the switch active for most of our listening.
At maximum volume, the SBD7500 gets loud enough to fill a small room with sound and doesn't overdrive the speakers. Mostly though, we think of this as a speaker for background music. In fact, when paired with the Internet radio streaming capabilities of the iPhone or iPod Touch, the SBD7500 acts as an inexpensive way to turn music apps such as Pandora and Last.fm into a proper tabletop jukebox. That said, if you're picky about sound quality and wouldn't mind a few more features, spending the extra money for the Altec Lansing inMotion Classic could be worthwhile.
Last.fm is a part of CBS Interactive, which also publishes CNET Reviews.