Dive deeper into your music.

Enjoy your music on a completely new level. An intimate, relaxed sound signature combines with outstanding precision and exceptional comfort — and now, extended sub bass — for a deeply moving experience.

Extended sub bass
Natural, warm sound
Comfortable open-back design

Your new desert island headphone

Every high-end headphone has its own unique personality. What if you could only own one?

Ever felt goosebumps from sound so real, it was as if the source was in the room with you? The non-fatiguing HD 660S2 gives people who love music an intimate way to connect more deeply with their favorite songs and artists. Breathtaking resolution and precision take you closer than ever to instruments and vocalists. Yet the sound is natural and balanced, never harsh or brash.

This warm, inviting signature combined with extended sub bass makes listening uniquely pleasant and rewarding. And with comfort this good, it practically begs you to keep going for endless sessions. That’s how HD 660S2 combines the best of many worlds to give you an intimate experience you won’t want to live without.

Sub bass expands the entire sound

Double the sub bass heightens your listening experience.

Traditionally, audiophiles don’t get too excited about sub bass. It can easily get sloppy or boomy and become a distraction. And that’s a shame — because there’s so much more to experience here than just the gut punch of a kick drum. Did you know the low B of a 5-string bass vibrates at 30.9 Hz? Or that the lowest note on a concert piano comes in at 27.5 Hz? And of course, extended sub bass makes bass-heavy genres sound fantastic, too.

And that’s the magic trick here. In doubling the sound pressure at the very lowest frequencies, we’ve nevertheless retained extraordinary precision and balance throughout the sub bass, mid-bass, and beyond. Most impressive is how this affects the listening experience. Extension on the low end changes everything — by creating more space for the sound. Against a deeper backdrop, highs feel more brilliant, the soundstage deeper, emotions stronger.

They feel as great as they sound

Comfy slippers, your favorite jeans, the HD 660S2. Some things just feel awesome to wear.

The velour earpads of the HD 660S2 can only be described as a tactile pleasure. With just the right amount of tension for proper acoustic positioning and supple padding, the headband won’t draw attention away from your music, either. As an open-back design, the HD 660S2 gives your ears an extremely comfortable climate, even for super-long sessions.

The low total weight and ergonomic headband rule out any potential discomfort on top of your head as well. Combined with excellent build quality made in Ireland, you’ll quickly grow attached to a listening experience that’s as physically pleasing as the warm, non-fatiguing sound at its heart.

How do you one-up a line of legends?

Some of the most neutral headphones in the world are a tough act to follow.

The surround is now more compliant, too, dropping the resonant frequency to 70 Hz. Considerable effort also went into optimizing the airflow around the transducer. There’s more sensitivity over the entire frequency spectrum because the magnet´s air gap works more efficiently now. Taken together, these measures result in even greater precision, speed, and resolution — with double the sound pressure at the lowest frequencies.

Frequency response graph comparing HD 660s2 and HD 660s

Features

Uniquely powerful vented magnet system for minimized distortion
Ultra-light aluminum voice coil with 300-ohm impedance for excellent impulse response
Intimate sound with great timbre and deep, accurate sub bass
Plush ear cushions and open design for maximum comfort
Outstanding quality designed in Germany, made in Ireland

What's in the box

HD 660S2 headphones
6.3 mm cable (1.8 m), 4.4 mm cable (1.8 m)
6.3 mm to 3.5 mm adapter
Carry pouch

Technical Specs

Transducer principle	Dynamic, open
Transducer size	38 mm
Frequency response	8 Hz - 41,500 Hz
Impedance	300 Ω
Sound Pressure Level (SPL)	104 dB (1 V)
Total Harmonic Distortion (THD)	< 0.04% (1 kHz, 100dB)
Style	Over-ear
Weight	260 g
Adapter	6.3 mm (1⁄4 inch) to 3.5 mm
Connector	6.3 mm (1⁄4 inch) jack plug, 4.4 mm balanced plug
Cable length	1.8 m
Magnetic ﬁeld	2.5 mT

Sennheiser HD 660s2 Audiophile Headphones