The HE-400i is expensive, but it's an extraordinary headphone. The sound is significantly more transparent and vivid than Bowers & Wilkins' headphone just lets you hear more deeply into your music. It's akin to looking through a cleaner window.. But the HE-400i's clarity shouldn't be confused with mere brightness or hyped treble -- the
As we said, the sound is open and airy. Hans Zimmer's majestic orchestral score for "Man of Steel" projected a bigger more expansive sound over the HE-400i than the P7. Instruments are clearly articulated and easily distinguished from each other. The mid-range is forward yet warm and and the headphones really excelled with albums such as the Punch Brothers' "The Phosphorescent Blues."
The P7 does have more bass weight and power, but the HE-400i's has better-defined bass isn't far behind. LCD Soundsystem's percussive beats driving "On Repeat" had plenty of oomph but lost some of their attack and crispness on the P7.
While the HE-400i is a more efficient (sensitive) headphone than the HE-400, your phone may not have enough juice to play the headphone loud enough. On David Carnoy's iPhone 5S, it was just loud enough with most tracks -- indoors anyway. With Steve Guttenberg's volume maxed out on his iPod Classic, the HE-400i was also barely loud enough. And editor Ty Pendlebury didn't have any major complaints using the headphone with his Samsung Galaxy S4. However Carnoy felt Sony's NW-A17 "Hi-Res" Walkman was a little volume challenged.
We could get a lot more volume out of the HE-400i when it was plugged into FiiO's X3 portable high-resolution music player ($240). Not only that, the HE-400i's sound quality significantly improved.
It's clear the HE-400i is designed for audiophiles, so it only sounds its best mated with an audiophile music player, or at home plugged into an AV receiver or headphone amplifier. The HE-400i's bass oomph, dynamic kick, and overall clarity show significant improvements when plugged into a device that's got a little more juice than your typical smartphone or iPod.
As far as this model vs. the step-down HE-400 goes, the 400i is the superior sounding headphone, with slightly more transparency, better defined bass, and slightly more forward mid-range. It's also the more comfortable and efficient headphone. We can't tell if those incremental advantages are worth an extra $200, but for many people they will be.
If you've always wanted to own a pair of high-end "audiophile" headphones but can't quite justify dropping a grand on a pair, the HiFiMan HE-400i is a good compromise. It's a superb-sounding headphone full-size headphone that features excellent build quality and an improved design that makes it more comfortable to wear than its predecessor.