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Finding a really good pair of on-ear headphones can be a challenge. While they're more compact than over-the-ear models, they often aren't as comfortable -- they sit on your ear after all -- and don't measure up sound-wise to their over-the-ear brethren, which also tend to do a better job sealing out ambient noise (at least the closed-back models do anyway). So it's easy to get excited when you come across an on-ear headphone like the Beyerdynamic T51i that not only features top-notch sound but is sturdily built and comfortable to wear. It's priced at $300 (£190 UK, AU$400).
Made in Germany, the T51i is a dead ringer for Beyerdynamic's earlier T50 (now discontinued), but the newer model has upgraded innards and sound.
The big difference between this model and the now-discontinued T51p, which we reviewed earlier, is the inclusion on a three-button inline remote and microphone that's designed to work with Apple's smartphones and tablets and may not fully function with Android or Windows devices.
The relatively lightweight (174 grams) mostly metal design doesn't have a hinged headband, but the earcups fold flat for easy storage in the supplied, well-designed carrying case.
Those earcups are padded with memory foam and they sit on your ears snugly without applying too much pressure. The headband conforms to your head nicely and doesn't leave a big gap in the temple region like a lot of headphones do. It's a comfortable headphone to wear for hours at a time without experiencing listening fatigue. That said, the cold metal design isn't for everyone and those with larger heads may end up with the metal part of the headband resting too close to their heads for comfort.
Isolation from external noise on the New York City subway was decent, though not up to the standards set by noise-canceling headphones and some over-the-ear models. Then again, the T51i sounds better than any of those headphones and it doesn't need batteries (all noise-canceling headphones do). While most audiophile headphones come with one-year warranties, the T51i's runs two years.
Impedance is rated at a highish 60 ohms, but the T51i sounded great plugged into both mobile devices (iPod Classic, iPhone 5S and Samsung Galaxy S5) and a Schiit Asgard 2 headphone amp at home.
The sound balance is slightly warmer than neutral, but detail and resolution are excellent. We found it pretty versatile -- it doesn't lend itself to one genre of music over another -- and for such a compact headphone its bass is surprisingly robust. It's not overdone or thick, but if you crave a rich low-end the T51i won't disappoint.
Brian Eno's ambient recording, "On Land," had a wide-open spacious quality, and it sounded nearly as big as we've heard from larger open-backed headphones like the Hifiman HE-400.
We put it up against Bowers & Wilkins' similarly priced P5 Series 2
Moving on to the Kronos Quartet, the T51i had just the right balance of acoustic warmth and clarity. The P5 sounded nearly as good, with just a tiny bit less body to the sound of the instruments. Both headphones are comfy, but since the T51i's round ear pads don't contact as much of your outer ears as the P5's flat pads, the T51i is less likely to make your ears sweat in hot weather.
The T51i also came out on top against the $349 Phonon SMB-02, another closed-back headphone that's getting a lot of buzz in audiophile circle. The SMB-02 plastic construction looks cheap next to the mostly metal T51p, and the bass punch pulsing through the Nine Inch Nails "Hesitation Marks" CD evaporated over the SMB-02s. Switching between the two headphones the T51i sounded considerably more natural and full.
In out next comparison, we put it up against the Sennheiser Momentum 2.0 , one of our favorite over-the-ear models in this price range (the Momentum 2.0 costs $60 more). In terms of sound, the T51i didn't quite measure up -- the Momentum has a bit warmer sound and bit wider soundstage. Also, the Momentum's cord is detachable and comes with a second cord with a built-in remote/microphone.
Stepping down to the smaller Momentum On-Ear 2.0 ($230), the T51i came out ahead, delivering more refined sound with better bass performance. Of course, sound is a matter of taste, and T51i's sound profile won't appeal to everyone (editor Ty Pendlebury, for example, found its sound a touch cold for his tastes).
This is a compact audiophile headphone that's well-built and delivers top-notch sound. Its design may not be for everyone, but it is comfortable and eye-catching. Like the the T51p, it's one of the best on-ear headphones we've tested, and has the added benefit of having a inline remote/microphone for mobile use.