The Good: The supremely comfortable Phonak Audeo PFE 232 earphones come with three "acoustic filters" that alter tonal balance for exceptional clarity and a wide-open soundstage. The Bad: The headphones lack the luxury look and feel we'd expect at this price, and they let in more external noise than they should. The Bottom Line: The Phonak Audeo PFE 232 aren't cheap, but critical listeners may well find their swappable Acoustic Filters (for fine-tuning the headphones' already excellent sound quality) to more than justify the $600 asking price. Phonak is one of the world's largest hearing aid manufacturers, so it's safe to say it knows more about sound than your average startup or celebrity-endorsed manufacturer that's just now dipping their toes into the lucrative headphone market. \n\nPhonak launched the Audeo brand four years ago, and its headphones are now widely distributed in Europe, but the U.S. ramp up has been slow. The company offers a complete line of earphones, with prices starting at $119 for the PFE 012 all the way up to $599 for the PFE 232. \n\nAll Audeo earphones are exceptionally comfortable, but the PFE 232's excellent sound to boot earns it a solid recommendation that competes with the very best in-ear models. \n\nDesign and features\n\nI expected lavish build quality from this $599 headphone, with something special like pure titanium earpieces or silver cables, but the PFE 232 is just a black and gray plastic headphone. \n\n\n\nAs for the "Perfect Fit" aspect of the design, the PFE 232 includes two separate sets of ear tips: three sizes of silicone and three sizes of Comply foam tips. There's nothing unique or special about the fit and Audeo hasn't made a breakthrough in that area, but the array of tips should let virtually any listener achieve the tight seal necessary to get the best sonic performance out of the headphones. \n\nThe headphone doesn't come with ear tips preinstalled, so you should try them all and see which creates the best seal -- that's standard fare for in-ear designs, but this is where it gets interesting: Audeo headphones use proprietary Acoustic Filters that change the sound of the earphones (the filters are extremely small discs that fit in the nozzle of each earpiece). \n\n\n\nYou get three sets of color-coded filters: gray, black, and green. The gray filters are installed when you unbox the earphones and they emphasize midrange frequencies, but sound the most neutral to me. The black filter boosts the bass and highs and the green filter pushes only the bass frequencies up. \n\nThe filters are packed in a small travel case, which comes with a special tool used to install and remove the filters in the earphones. Few headphones allow this sort of fine-tuning.\n\n\n\nThe PFE 232 comes with a 48-inch-long, tangle-resistant cable with an inline microphone and volume control compatible with iPods, iPads, iPhones, and most smartphones using a 4-pole 3.5mm jack. You also get a standard cable without the microphone and volume control. Both cables are user replaceable, so when they eventually break you can pop on a new one. \n\n\n\nThe thin, flexible earphone cables are designed to loop back behind your ears, and Audeo supplies curved silicone "ear guides" that slip onto the cables to help secure the earpieces in place. The guides helped, but the earpieces sometimes lost the seal and would require some fiddling to re-establish the tips' seal in my ears to get the best possible sound. \n\nAdditionally, the tiny "L" and "R" markings on the inside lobe of the earpieces aren't easily legible in low-light situations.