• Audiophile sound: The natural, relaxed, high-fidelity sound offers an intimate listening experience with great timbre and deep, accurate sub bass.
• 38mm high-performance transducers built in Ireland: Steel mesh damping follows the driver’s geometry to control air displacement for precise sound.
• Vented magnet system: The magnetic yoke includes milled air vents for optimal ventilation to minimize distortion.
• Aluminum voice coil: Specially developed ultra-light voice coil with 300-ohm impedance for excellent impulse response.
• Open-back earcups: Facilitate the natural expansion of sound waves for a hi-fidelity spacious soundstage.
• Exceptional comfort: Open elliptical earcups provide breathability and luxuriously comfortable velour pads provide hours of fatigue-free listening.
• Outstanding build quality: Designed in Germany, made in Ireland, each element is carefully selected to meet exacting standards.
• Detachable cables: Para-aramid reinforced cables with OFC copper ensure signal integrity and a very low handling noise.
• Ergonomic design: The low total weight and ergonomic headband eliminate potential discomfort on top of the head
• Global 2-year warranty: Offers peace of mind for your audio equipment investment.

How do you one-up a line of legends?

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

Sennheiser headphones have inspired generations with their balanced, natural reproduction. Recognized as a benchmark for neutral audiophile sound, the original HD 600 from 1997 still shares visible and audible DNA with the latest in the lineup, the HD 660S2.

Despite the previous HD 660S from 2017 standing as one of the world’s most popular audiophile headphones, some customers nevertheless wanted one very specific enhancement: even deeper bass. Enhancing this heralded audio design without detracting from its many strengths was, however, a daunting task. So, our engineers set out to systematically identify and exploit every opportunity in their quest to improve on the acclaimed HD 660S design.

We adjusted the compliance of the surround, for instance, dropping the resonance frequency to 70 Hz. Considerable effort went into optimizing the airflow around the transducer. The coil in the HD 660S2 has also been revised to match the legendary HD 600 & 650, resulting in an impedance of 300 ohms. The new coil exhibits much higher magnetic force and electrical damping for cleaner impulse response. It also increases sensitivity over the entire frequency spectrum by using the magnet’s air gap more efficiently.

Taken together, these efforts and more have paid off in spades. The new version builds on all the strengths of its formidable predecessor; the same world-class precision and resolution still let you pick out individual instruments like with no other headphone. But sound pressure at the lowest octaves has doubled, so now, you can feel the music more than ever before — with all the depth and weight that ultra-low frequencies invoke. The unique combination of impactful bass combined with the warm tuning and smooth treble is a revelation for music lovers, an even better way to lose yourself in comfortable, non-fatiguing, high-end sound — while feeling its full low-end power.

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 favourite 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 favourite 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. And now, the headphone’s warm, relaxed tone is reflected by their timeless styling with elegant bronze accents. A storage pouch is also included.

It’s all about connection

Connect with your music by plugging into your source of choice.

We packed your HD 660S2 with a set of essential cables, versatile enough to connect to vintage classics and modern solutions alike. Each cable is impedance-matched with ultra-low capacitance. The ¼-inch / 6.3mm stereo connector offers the audiophile-standard plug for connection to devices such as headphone amplifiers and A/V receivers, digital audio players, computer-based workstations, analog gear, and more.

Unlike other HD6 Series models, a balanced 4.4mm cable is also included in the box, opening a pathway to a popular balanced output devices like DAC-amps, DAPs, and dedicated amplifiers. A balanced headphone setup offers an even lower noise floor with great dynamic range when connected to balanced source/amp circuit outputs. You’ll experience a wider soundstage, tightly controlled transients, and impossibly-clear instrument separation.

Each cable is 5.8 feet / 1.8 meters long to accommodate all types of listening, and a flexible adapter is also included to reduce the 6.3mm to 3.5mm.

What’s Included

• HD 660S2 headphones
• 6.3 mm cable (1.8 m)
• 4.4 mm balanced cable (1.8 m)
• 6.3 mm to 3.5 mm adapter
• Carry pouch
• 2-year warranty