Once we hooked up the external antennas and fixed the aspect ratio, we moved on to performance testing, which is ultimately where this Polk hits its stride. Cream's Royal Albert Hall 2005 DVD rocked out with a vengeance. Jack Bruce's bass guitar and Ginger Baker's drums packed a wallop and didn't distort, even when we played the I-Sonic at a room-filling volume. Bass definition among tabletop radios is too often sacrificed to provide the impression of big, booming bass, but thanks to Polk's PowerPort venting technology, the I-Sonic's bass was powerful and surprisingly tuneful, so we could pick out each note.
The I-Sonic's two rear speakers and digital processing rely on reflections from the wall behind the unit to create a large sound. We experimented with different placements of the I-Sonic in our room, but the surreal helicopter battle sequences on the Apocalypse Now DVD weren't as spacious sounding as we get from a 5.1-channel speaker system. That said, once we were involved with the film we never thought about the size of the I-Sonic. Dialog intelligibility was another strength of the little system. Treble and bass controls are also available to tweak the sound of the system.
The Polk Audio I-Sonic's CD sound was exceptional. Bass, midrange, and treble were perfectly balanced, so the I-Sonic sounded equally accomplished with all types of music. Likewise, the sound quality on radio stations was generally superb, although the FM reception of I-Sonic was merely average, so it failed--even with the external antenna--to pull in hard-to-receive college stations without static background noise. HD-encoded FM stations produced some fidelity improvement over non-HD stations, with more treble detail and dramatically reduced levels of background hiss. Some stations do HD radio better than others, so you'll potentially hear some variations in sound quality from station to station. Meanwhile, XM satellite radio reception was on a par with that of most other XM-ready systems we've heard.
Like many modern A/V devices, the I-Sonic does have an upgradeable firmware; they can be uploaded from a CD-R or via a USB port on the back (it's strictly for service and has no other function). Polk provided us with an update disc to correct a small glitch that the I-Sonic experienced when switching from DVDs to CDs; following the onscreen prompts loaded the new firmware in a jiffy and fixed the problem.
In the end, even with its handful of noticeable and somewhat irritating quirks, the Polk Audio I-Sonic represents a strong challenge to the Bose Wave Music System and its ilk. From a features standpoint it's an easy winner, and it holds its own--if not beats--the Bose from a performance standpoint, too. Yes, it costs a pretty penny, but when you consider that rivals such as the forthcoming $600 Tivoli Audio Music System don't offer satellite radio, HD radio, or DVD options, the I-Sonic almost looks like a bargain. Hopefully, Polk will be able to further refine the system's menus and options with further firmware upgrades. If it does, we'll update our review to reflect those changes.
Freelancer Steve Guttenberg contributed to this review.