Headphone enthusiasts can be a fickle bunch, but if you manage to pull a group of them away from their amps and Super Audio CD players to ask them to recommend a pair of cans, most would point you towards the Sennheiser 600-series. Over the past 25 years, Sennheiser has been trickling out minor updates to the line, but the latest addition—the new HD 660S2—address a common complaint with recent models.
For those proud to distinguish themselves as true audiophiles, there’s no such thing as audio gear that’s too expensive. If they have to choose between a new car or a similarly-priced pair of headphones that promise to inch them closer to acoustical nirvana, then you’ll probably find them taking the bus to work. That’s why headphones like the $16,000 Sennheiser Orpheus HE90 and their follow-up, a $55,000 upgraded model simply called the Orpheus, exist.
But you don’t have to destroy your budget to treat your ears. Back in 1997, Sennheiser also introduced its HD 600 headphones, which offered excellent sound, solid build quality, and a comfortable design for $450 ($832 in today’s money). They had an impressive balance of everything headphone enthusiasts wanted, including repairability, without threatening you with total financial ruin. We’re not going to pretend like every old school audio connoisseur could afford $450 headphones, especially with inflation, but Sennheiser still sells these, now with a $400 price point. Given that Apple now sells $550 AirPods, the HD 600 don’t exactly seem outrageously overpriced by comparison.
The fact that Sennheiser still sells a 27-year-old pair of headphones is a testament to the HD 600's capabilities, but over the years, they’ve been joined by upgraded models including the HD 650 and the HD 660S, which have introduced new features like swappable cables and upgraded materials. Today’s reveal is the Sennheiser HD 660S2.
Most consumers would probably struggle to hear the difference between the HD 660S and the new HD 660S2, but Sennheiser is positioning them as a solution that addresses a common complaint with other recent models in the line: disappointing performance in the low-end frequencies. The company promises that “revised 300-ohm transducers” lower the headphones’ “resonant frequency from 110 Hz (original HD 660S) down to 70 Hz for hefty kick drums that move with ease.” The HD 660S2 also benefit from “enhanced sub-bass tuning” and “a refined listening experience thanks to improved transducer airflow.”
That last upgrade is an important one to note if you’re considering any of the models in the 600-series lineup. These are all open-back headphones, which means that, unlike offerings from Sony and Apple, they won’t stop people from hearing you blast Britney on the subway. The HD 660S2 are actually designed to leak sound to improve their performance. So they’re terrible for use in the office or on the bus or really anywhere other than the privacy of your own home. The open-back design also means any kind of noise cancellation is just not an option.
The Sennheiser HD 660S2 also aren’t wireless, but do include a pair of 5.8-foot swappable cables with quarter-inch and 4.4-millimeter stereo plugs, as well as an 1/8-inch adapter for those pairing the headphones with an amplifier, which is actually recommended to take full advantage of their capabilities. Long story short: these aren’t designed to compete with the feature-packed Sony WH-1000XM5 or the Apple AirPods Max. The $600 HD 660S2 are for those who want to enjoy the high-res audio they pay a premium for to the fullest, without having to worry about a phone call or a random message notification disturbing their music. They’re also a player in the reference space, which helps audio engineers tune their music. You can pre-order from Sennheiser’s site, if either of those sounds like you.