The new HD 660 S lets you enjoy sophisticated audiophile sound in even more listening situations. The successor of the legendary HD 650 excels with the improved performance of its new transducer design. Thanks to its lower impedance, it delivers reference-class sound also when connected to hi-res mobile players, thus offering much greater versatility. The HD 660 S is an elegantly designed piece of high-quality engineering that indulges the demanding listener with aural precision and great wearing comfort. The highs on the HD 660S are definitely the brightest of the HD 600-series headphones, and while I would not call them veiled, they are definitely still on the warmer side. For frequency response I only had two minor issues with the HD 660S’s treble. The more noticeable one was a peak in the lower treble at 5.5k, that–like on the HD 58X–made the HD 660S’ timbre sound a little bit more congested than on the HD 6XX and HD 600. Additionally, the frequencies above 10k could use a little more energy for my preference, I thought that they sounded a little muted. Aside from that, I still really enjoyed the treble and I found it to be very smooth overall. For resolution I think that they have very good detail in the highs; they are very resolving and clean in their delivery. Comparing them to other Sennheiser headphones, I thought that for resolution they were a little more resolving than the HD 6XX, and were a significant upgrade in treble detail from the HD 58X. I personally thought they were more detailed in the highs than the DT 1990 Pro, and they were on par with the HiFiMan Sundara. Soundstage and Imaging The HD 660 S still has the somewhat tight clamping force, which can be remedied as mentioned above. Once set, the HD 660 S has the same quite comfortable, head-hugging fit and light weight of its predecessors. There are a few subtle differences. I spent weeks feeding the HD 660 S with a hugely varied playlist stretching from Bjork to Wagner, and Ed Rush to Fleetwood Mac, and across everything from vinyl to CD to hi-def audio via Tidal’s excellent streaming service. I also used them in tandem with a range of kit including a Chord Mojo, TC Electronics BMC-2 and a Naim Uniti Atom.

Anyway, what is really important is that sonically HD 660S is quite different from the HD 700, which for me is a good thing. The Sennheiser HD 660 S are comfortable, have a great soundstage and a non-fatiguing combination of clarity and rich tone. I’d like to stand by my audio chain, with which I’m very familiar at this point and believe is more than adequate to compare these headphones.There is although a little difference, the mids aren’t so forward as with the HD 650. The HD 660S places them only slightly forward, it doesn’t push them that hard, so it sounds more balanced, less melancholic and musical. It’s not a big difference, but is noticeable. TheHD 660 S2's upgrades look like sensible ones, butSennheiser nevertheless has a big task on its hands as it tries to satisfying the fussiest demographic of music lovers. Starting with the build quality, HD660S is quite sturdy. One thing that really feels different when switching from Audeze LCD-MX4 to HD660S is the weight, HD660S is incredibly light, and even in comparison to something lighter, like Ultrasone Signature DXP / Signature Studio, they still feel quite a bit lighter.

Renowned for their neutrality and musical delivery, Sennheiser’s HD 660 headphones have a cult following. Now in S2 form, the updated model features lighter voice coils and improved airflow, helping to enhance the bass response. Dropping from 110Hz to 70Hz, the bottom end now has noticeably more impact, without spoiling the headphone’s legendary sonic precision.

Let's talk about the sound: I've listened to the headphones with several amplifications, with different powers and more importantly different output impedances. The HD700 is less correct and less timbrically competent, but its soundstage, warmness and the particular high frequency detail gives to this headphone a somewhat special status (which you can love or hate). If you like its sound perspective, the Hd660S can't compete. Instead, if strict timbrical accuracy is what you seek, the 700 will have some difficulties to compete with the HD660S. It comes with…the same exact cable connectors as the other two. In a way, I’m sure this is appealing to longtime fans who have spent on aftermarket cables that they’d like to carry on over – but the connectors on these are some of my least favourite available for any headphone. Like the build quality, comfort is also very good on the HD 660S. Thanks to their mostly-plastic construction, these are extremely light (only 260g or so), so I doubt anyone will have weight issues with these. The pads use a fairly dense foam wrapped in velour and are very soft on the skin, I only wish that they were a bit wider on the inside as some people’s ears might touch the inner sides of the pads. The only problem I have with the comfort is that out-of-the-box, the clamp force can be quite vicious. Nonetheless, this can easily be alleviated by extending the headband all the way out and gently flexing the part that extends. Sennheiser HD600 and HD650 have both been emblems of quality in the audiophile world for almost ten years now, with HD660S coming to change that and bring a new headphone to the table. We're having a look into what it brings to the table, and into how it changes the headphones that are already loved by thousand of people from all over the world.

The HD 660 S features a new transducer design developed by Sennheiser. This results in improved control of the diaphragm movements thanks to a specially manufactured precision stainless steel fabric, which is adapted to the contour of the diaphragm. Extremely light aluminum voice coils ensure the highest impulse fidelity. The transducers are carefully selected and paired by hand to ensure consistently narrow (±1 dB) tolerances. Going by Hollywood’s release schedule, remaking old films is big business; forget novelty, it’s about reinventing and reimagining the classics for a new generation. It’s an approach that doesn’t seem out of place with classic hi-fi, either, as that’s exactly what Sennheiser has done with its latest headphones, the HD 660 S. Sennheiser HD 660 S review: What you need to know These headphones are a follow-up to the Sennheiser HD 650, considered a classic pair for well over a decade now. Sennheiser retains the warm, accessible tone for the HD 660 S, making this pair easy to recommend to virtually anyone who can afford the high price.Yes, they are still here, they haven’t left. Probably the biggest virtue of these headphones is the very present mids that seem to infuse joy directly into your central nervous system.

There aren’t many headphones in this world that gave me goose bumps when listening to violins. The headphones in the HD 6xx line have always known how to do this. I cannot explain how, but they simply excel on mids and, yes, they highlight them a bit too. The DT880 initially comes across as the most detailed of the three because of its brightness and more aggressive presentation. Upon closer listening, it maintains a slight edge over either Senn in detail retrieval in the bass and the treble. The 6XX and the 660s are slightly more detailed in the midrange than the DT880. The 6XX probably is the one with more resolution in the mids, and the 660s is the one that’s smoother and more forgiving. Both of these qualities have advantages in certain situations. The HD 660 S is not an embellisher. Rather, it clearly highlights the weaknesses of a sound source, such as when a mix is too flat. As such, you can clearly hear sound and level variations between newer and older productions. Their design and fit is a little more special than that of the fairly conventional-looking HD 660 S too. However, while I no longer have the HD 700 to hand for a direct A/B test, comparisons with other contemporaries suggest that pair is “different” rather than flat-out better. My interests/hobbies are fishing and relaxing to audio products and reviewing them to help other decide on what products would work for them. Few things make me as an audio enthusiast/reviewer feel more accomplished than when someone tells me that I helped them find the type of sound they've always been looking for.At the end of the day, you're probably wonder where is the HD6XX line headed towards, and we feel it is headed towards greatness. Sennheiser has shown great respect for their customers, and they have shown improvements organic with their customers demands when releasing the HD660S, which is a more versatile headphone than both the very clean, but slightly clinical sounding HD600, and the too lean and too smooth HD650. They simply made a headphone better than either, one that not only bests both, but will also be hard to beat for a long time to come, as its predecessors were iconic headphones for many years so far. In my opinion, the HD 660 S is the true reference in the HD 6xx line, with the HD 600 coming second and the HD 650 coming last, with a more colored sound. I would like to say that first and foremost I am NOT an “audiophile” but rather an audio enthusiast. I listen to music to enjoy it. Do I prefer a lossless source? Yes, of course. But I can still be very happy streaming from Pandora or even YouTube's “My Mix” playlist. I also prefer equipment that sounds the best to me personally regardless of what frequency response it has or rather or not it's “sonically accurate” and I always have and shall continue to encourage others to do the same.