"Smart Volume" works more like a solid noise reduction filter, which really helped when we wanted the i525 to maintain a certain level of sound without having to reach for the remote to adjust the volume.
These X-Fi effects can also be mixed and matched depending on preference. In our testing, we found ourselves using the Crystalizer on the radio and left them off when using an iPod or auxiliary source.
Performancewise the i525 really delivers. An impressive amount of sound emanates from this small box, easily filling up our 18-foot-by-18-foot bedroom and 25-foot-by-25-foot audio testing room. From Green Day and Kings of Leon to Lady Gaga and The Cure, the i525 handled everything with ease. We were able to tweak bass and treble settings on-the-fly, which let us find that optimal zone for the best-sounding result. We'd easily put the i525's sound quality up against the $250 Boston Acoustics Duo-i plus.
There's a surprising amount of bass output here, and turning the volume all the way up never resulted in a harsh distortion or tearing. In fact, it's here where the i525 really shines. It's not exactly portable, but if there's access to an outlet on a deck or patio, the i525 could easily entertain at a barbecue.
A plastic remote control is included, and though it feels a bit on the flimsy side, we had no issues with its performance. In fact, we were really happy with how well it controlled our iPod and iPhone, and even the apps therein. We'll get into the details of that experience next.
Like a lot of the iPod-compatible radios we've tested, the i525 only claims compatibility with iPods and not necessarily iPhones, because of the lack of shielding that requires the user to switch the phone to airplane mode.
With the i525, we experienced the same preliminary issue, but didn't need to do much other than dismiss our iPhone 4's alert that the product wasn't compatible. After that, it was smooth sailing, as we were able to comprehensively navigate through our iPhone's music library, including artists, songs, and genres--something we don't usually see on a lot of these radios. Even more impressive, we had no issues using the remote control to advance tracks in the Pandora and the Last.fm iPhone apps.
Overall, the i525 is an impressive, fully featured package. Its $150 price tag places it among the more-expensive devices on the market, but its great sound, feature set, and comprehensive iPod control make it worthy of such an investment.