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Sennheiser HD 660 S 2
HD 660S2
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
Features
- Uniquely powerful vented magnet system for minimized distortion
- Intimate sound with great timbre and deep, accurate sub bass
- Outstanding quality designed in Germany, made in Ireland
- Ultra-light aluminum voice coil with 300-ohm impedance for excellent impulse response
- Plush ear cushions and open design for maximum comfort
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.
As far back as the HD 580, high-end Sennheiser headphones have inspired generations with their balanced, natural reproduction. Recognized as benchmarks for neutral audiophile sound, the HD 600, HD 650, and HD 660S all share visible and audible DNA with the HD 660S2. The revised coil of the S2, for instance, now matches the 300-ohm impedance of the legendary HD 600 & HD 650. This new coil also provides higher magnetic force and electrical dampening for cleaner impulse response.
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.
What's included
- HD 660S2 headphones
- 6.3 mm cable (1.8 m), 4.4 mm cable (1.8 m)
- 6.3mm to 3.5mm adapter
- Carry pouch
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Professional Reviews 90/100
Deliciously Crispy
Sound Quality
92/100
Comfort Fit
83/100
Build Quality
89/100
Features Usability
84/100
Value for Money
93/100
The HD 660 S 2 delivers fast, tactile bass, a focused midrange and smooth, revealing treble in an open-back design built for absorbed home listening. StereoNET United Kingdom found its timing, dynamics and mix insight especially compelling, while the expansive imaging and robust, lightweight construction round out a remarkably accomplished all-rounder.
What Reviewers Are Saying
Pros
Fast, tactile and well-timed bass adds impact without clouding the midrange.
Highly revealing, tonally balanced sound with focused mids, polished treble and strong rhythmic dynamics.
Well-made, durable-feeling construction with detachable single-ended and balanced cables included.
&
Cons
The initially firm, vice-like fit may require a break-in period before it becomes comfortable.
Soundstage is expansive and images well, but is not among the most cavernous available.
SOUND QUALITY PERFORMANCE 92/100
Reviewers found a fast, open and highly revealing presentation with an unusually well judged tonal balance. Its strongest traits are its rhythmic agility, polished treble and ability to expose detail, while the soundstage is expansive rather than exceptionally vast.
Bass
92/100
StereoNET found the revised low end more impactful and accurate than the older HD 600-family tuning. On electronic music, sub-bass was described as bouncy, tactile and exceptionally well timed rather than simply exaggerated.
Midrange
91/100
The midband was described as better focused and more revealing. This sits within a tonal balance the reviewer considered close to perfect, with less upper-bass emphasis obscuring the central range.
Treble
92/100
Treble is presented as polished and smooth, particularly on hi-hat and cymbal work. Crucially, the refinement does not come at the expense of treble information, which the reviewer says remains intact without glare.
Resolution Detail
93/100
The HD 660 S 2 was called a very revealing headphone, capable of showing what is happening deep in a mix. Its open, detailed character is presented as a major part of its appeal across different music.
Soundstage Imaging
89/100
StereoNET reports strong imaging and an expansive overall sense of space. The reviewer also notes that it is not among the most cavernous-sounding headphones, tempering its spatial scale somewhat.
Dynamics
93/100
Rhythmic and dynamic alacrity were singled out as qualities that make the design special. The review also praises its nimble timing and ability to get convincingly into the groove of electronic music.
Assessments of Build Quality, Usability, and Overall Propositions.
Comfort Fit
83/100
The pads and clamp feel firm, even vice-like, when new. The reviewer says they improve substantially with use and ultimately become very familiar and comfortable, but the break-in period remains a real consideration.
Build Quality
89/100
StereoNET describes the HD 660 S 2 as very well made. Its high-quality plastic construction is praised for combining strength with enough pliancy to resist breaking easily.
Features Usability
84/100
This is a conventional open-back wired headphone, supplied with 6.3 mm and 4.4 mm balanced connections plus a 3.5 mm adapter. The reviewer found it easy to use overall, although there is little further discussion of ownership features or long-term practicality.
Value for Money
93/100
At roughly £680, StereoNET considers the HD 660 S 2 affordable in context and argues that its performance makes extravagantly priced alternatives harder to justify. That is strong praise for its competitiveness within the enthusiast open-back market.
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