Sennheiser HiRes Audiophile Headphone (HD 660 S)

Product Information

It should be noted that I have absolutely no affiliation with Sennheiser, I am not receiving any incentive for this review or to sweeten things out. This review is not sponsored nor has been paid for by Sennheiser or anyone else. I'd like to thank Sennheiser for providing the sample for this review. The sample was provided along with Sennheiser's request for an honest and unbiased review. This review will be as objective as it is humanly possible, and it reflects my personal experience with Sennheiser HD660S. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in Sennheiser HD660S find their next music companion. And where several of my more aggressively noisy test staples – Metz’s Strange Peace album, for one – become strident and wearing on the HD 580 Precision, the HD 660 S’ more forward mid-range and tighter bass make it possible to listen to the entire album from start to finish without reaching for a pair of earplugs. There’s enough clarity to separate the rolling waves of guitar distortion and clattering drums, and even the brash, overdriven drum and bass of Current Value’s Bigger Picture manages to bounce along excitedly without ever veering too far into harshness. When changing the HD 650 with the HD 660S after a non-stop 2 hour listening to the HD 650, I can feel that the veil has lifted, the mid-bass stops rattling and clipping and the harmonic distortion feels lower. As long as you’re buying for the home rather than portable use, there’s very little to dislike about the Sennheiser HD 660 S design.

Starting with the bass of HD660S, it is a clear, clean and snappy bass. It has excellent speed and clarity, but it is not a basshead oriented bass. It has enough speed to make you tap your feet, it has enough body to give music an interesting presentation, but it isn't quite a lot in amount, being quite close to what would be considered a neutral bass. This is not something negative in any way, and in fact, it could be considered a strong point of HD660S, but it should be noted that if you're craving large amounts of bass, there are headphones that provide much higher amounts of bass.Sennheiser has been around since like forever and they’re one of the most respected companies in audio. In the past, Sennheiser has impressed us with a lot of top-quality products like the HD800, the HD 800S and many 5XX and 6xx series headphones. Sennheiser has also upped their IEM game and they have successfully launched the IE 200, IE 300, IE 600 and IE 900 inear monitors. In world of audio, there are two kinds of frequency response targets, fun and flat. Flat is for the profesionals, its meant for production work not for joy, atleast that is the common opinion. Then there is fun tunning, unlike flat, there is not just one target. The current fashionable fun target curve is the Harman curve and its derivates. Before rise of Harman, the popular curve was the V shape, boosted bass, boosted treble. There is quadrillion unique fun curves made for specific headphones. Each fun headphone with its own one of a kind fun curve. But let me now talk about the individual characteristics of the sound signature so that I may be able to convey my thoughts on the HD660 S better. Many critical listeners demand a neutral sound from high-end cans, and the somewhat tame bass performance oftheHD 660 S2’s predecessors was a common gripe.

This is pretty much it, but this will vary a lot with different sources since you can get a widely different signature form HD660S from different sources, so this profile won't be quite that universal in the end. Everybody shits on HD660S, I think its best sounding out of the box headphone I ever tried, I absolutely love that frequency response!Moving down the headband still features it very nice and firm size adjustments that leave no doubts to the user what the cups have moved to a different size, for each adjustment is made with a notable pop. On that note, this headphone has more adjustment sizes than I think anyone will need. Unless you’ve a really tiny head, you’re more than likely to find the optimum adjustment out of this headphone. This is why I feel so strongly about the initial presentation of a product, and I feel it’s truly a shame more people don’t. But with all that aside, let’s discuss how this products introduced itself shall we? I believe I received a very nice “handshake” with the HD660 S, as I did with its predecessor the HD650. Sennheiser includes a very nice cardboard box that is really just a smaller version of the HD800 S box minus the nice silky material and the stop strap. The box itself, like the HD800 S, is my EXACT want in a headphone box. The exterior si super simplistic as in all it shows is a picture of the product and its name. This, to me, shows the competency and confidence of an audio manufacture.By doing this I see it as them telling their customers listen to my product and let it speak for itself; let it SHOW you what it can do instead of my boggling down the box with fancy words and look-at-me’s so that I can pretend to be competent. And for a company as legendary as Sennheiser, who’s over 70 year experience shows, they’ve got more than enough competence. So in other words, before I even get into this box, I’m extremely excited to put it on my head and see what it can do.

grams feels like nothing to me now after such a long time with the Focal and ZMF headphones. That being said, I find the comfort to be largely affected by the amount of clamp these can have while new - a few hours in and I was feeling the pain. Once on your head, however, they stay put so you can headbang away without fear of them falling off. The cushioning on the headband is adequate, considering its low weight.I begin to understand this new headphone. As before, compared to the HD600, the HD660S is the one that sounds with the most powerful frequency extremes, fuller and cleaner. There is a somehow attenuated mid-high frequency area compared to the 600, balanced by a rise slightly above it. This contributes to the feeling of a cleaner sound, but in direct comparison the voices seem timbrically a bit "muted". But if one get used to the 660S' sound, it seems that maybe the 660S is right, while the 600 emphasizes some harmonic components perhaps a little more than the necessary (but very pleasantly). Nevertheless, some chorus lines seem slightly better outlined with the 600, while on the other hand the 660S has better positioning of the orchestra and chorus sections. Overall the 600 seems timbrically more "phoney" sounding than the 660S. What I enjoyed immediately after switching to the HD600 was this sense of depth the sound gained over the HD660S. While the newer headphone is punchier and more impactful, it can sound thin and strident compared to the HD600. What more can I say? We have the same built and design that we are familiar with for more than 26 years. If you listen to acoustic music, jazz or classical, the HD 660 S becomes an obvious recommendation.

For the HD660 S2, Sennheiser revised the coil of the S2, and it 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 – according to Sennheiser – 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. Sennheiser HD660S, HD650, HD600, Matrix Audio X-Sabre Pro, iFi iPurifier2, Audio-GD Master 9, Audeze LCD-4, FiiO X3 MKIII, HeadAmp Pico & Pico Power The fit and comfort depends a little on how much time you give them. Out of the box, HD660S is quite tight and their fit is quite tight on the head, and while this might mean that they won't be fully comfortable for any head, it also means that they are pretty secured in place, you can bang your head quite a bit without them falling off your head, and you can do quite a bit of movement without fear that they'll fall. It is a known fact that HD6XX series headphones become quite a bit more comfortable with some wear, and we are able to confirm this, after wearing them for a few weeks they can get so comfortable that you may forget they are on your head. The earpad width is large enough for most ears, but it is quite a bit smaller than that of Amiron, for example, which is quite a bit larger. The earpad material, on the other hand, is really nice to the touch, pretty soft, but with a texture, allowing for an excellent overall comfort.Sennheiser HD660S + Burson Play - Burson Play is a great little device created by Burson, a rather loved and well-known company. Play is most an Audiophile-Grade, modular, integrable DAC/AMP for desktop, and especially for desktop PCs. Its power is quite fit for HD660S, and it is a good way to prove that HD660S can sound pretty sweet on a proper desktop-class setup. The beauty of Burson Play comes from the fact that you can integrate it in your PC setup, so you can plug HD660S, or any other audiophile-grade headphone, directly in your battle station, and just enjoy audiophile-grade sound without having more devices on your desk or table. The sonic performance is quite variable with Burson Play, as it allows the user to change its OP-AMPs, but the most basic configuration offers a warm and smooth sound, with a pretty good soundstage, which pairs well with HD660S. The HD 660 S have a more precise timing, giving the sensation that musical notes are fuller and more precise, better rounded, with a clear definition. I want to mention that, from the 3 models, the HD 650 scaled the worst in this regard. I can feel myself distracted by the micro-echo and harmonic distortion in the bass and mid frequencies, and the slight veil over the notes also impairs the listening experience. By comparison, the HD 600 seems to bring a fresh breath of air and doesn’t have as many shortcomings. 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.