Sennheiser HD 660S2

The HD 660S2 is a warm, vocal-forward masterpiece that needs a real amp to shine. Buy it for the sound, not the plastic.

The sound here is the story. Sennheiser claims they doubled the sound pressure at the lowest octaves compared to the original 660S, and you can hear it. The sub-bass extension down to 27.5Hz means a piano's lowest note actually lands with weight, not just a suggestion of it. Vocals are the real star though. Lifelike, intimate, and placed right in the center of your head. The 300-ohm impedance and ultra-light aluminum voice coil give it excellent impulse response, so transients hit fast and clean. But here's the catch: this thing is thirsty. Plug it into a phone or a cheap dongle and it sounds thin and lifeless. Feed it proper power and it opens up beautifully. The soundstage is intimate rather than wide, which some folks love and others find claustrophobic. We're in the latter camp for gaming, but for critical listening it's a feature, not a bug.

The obvious comparison is the Bowers & Wilkins Px8 S2. The Px8 gives you wireless, ANC, and a more premium build, but it can't touch the 660S2's vocal realism and sub-bass texture. The Sony ULT Wear and JBL Tour One M3 are lifestyle headphones with big bass and lots of features, but they're not in the same conversation for critical listening. The Bose QuietComfort Ultra is the comfort king and has better ANC, but its sound is more processed and less honest. If you want one headphone for everything, get the Px8. If you want a dedicated listening tool and already own an amp, the 660S2 is the better buy.

Here's where it gets tricky. US prices swing from USD 370 to USD 680 depending on where you look, and that's a massive spread. At the low end, this is a steal. At the high end, you're paying more than a pair of Bowers & Wilkins Px8 S2 for a headphone with no wireless, no ANC, and a mic that scores in the 15th percentile. If you're in the US, hunt for the USD 370 listing and don't pay a cent more. In Europe, the EUR 373 to EUR 439 range is tighter, but the same rule applies: buy at the bottom of that range or wait for a sale.

The Sennheiser HD 660S2 is a headphone that knows exactly what it is: a warm, detailed, open-back listening tool for people who care about music more than features. No Bluetooth, no ANC, no app. Just a 42mm dynamic driver, a 300-ohm impedance that demands real amplification, and a sound signature tuned to make you forget you're wearing headphones. The one thing to know? If you've got a decent DAC/amp and a quiet room, this is one of the most natural-sounding pairs of cans you can buy under a grand. If you're plugging straight into a laptop, don't bother.

If you're looking for a wireless headphone with ANC for commuting or travel, this isn't it. Go get the Bose QuietComfort Ultra or the Sony ULT Wear instead. If you want a wide, spacious soundstage for gaming or orchestral music, the 660S2's intimate presentation will frustrate you. And if you don't already own a DAC/amp, factor that extra cost in before you buy.

The HD 660S2 is a specialist's headphone, and it's unapologetic about it. For critical listening with a proper amp, it's one of the best values in audiophile audio right now, especially if you can snag it at the USD 370 end of the spectrum. The plasticky build and narrow soundstage are real drawbacks, but they fade away once the music starts. If you're serious about sound and don't need wireless, buy it. If you want one headphone for everything, look elsewhere.