Sennheiser HiRes Audiophile Headphone (HD 660 S)

Product Information

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. I'll not wax poetic this time regarding the long and storied history and my experiences with the HD 6xx family of Sennheiser headphones. For that, simply go have a look at my " The Very Important Sennheiser HD 580, HD 600, and HD 650" review.

For this sound section I will be going over the HD 660S’ tonal and technical performance while drawing comparisons to some of its competitors, as well as some of Sennheiser’s other offerings; namely the DROP X Sennheiser HD 6XX and HD 58X Jubilee. Bass As a whole, the frequency response appear to be the most correct and complete on the HD 660 S. Yes, they’re a little more neutral from the midrange upward, but they never sound boring for their price category. 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.

To make myself fully understood, the headphone doesn’t have a severe sub-bass deficiency, some people categorizing it as bass-heavy, but you cannot understand what real sub-bass is until you give a listen to some well amplified high-end planar magnetic headphones. The highs presented themselves clean and airy, with a good balance between technical show-off and naturalness. The highs are somewhere in the middle, not overly natural, but also not overly bright and sibilant.

I think that the HD 660S performs decently well for dynamics. The HD 600-series definitely is not known for being punchy, but I still thought that the HD 660S performed slightly better than its predecessors in this category. It was by no means the strongest out there, but the HD 660S did have some punch slam. I found microdynamics to be fairly well-defined as well, as I felt like all elements in the mix had a fairly good sense of tension and presence. Overall, I would say that the HD 660S perform well in this category, although I do think that other headphones like the Sundara and DT 1990 Pro make for a more engaging and energetic experience in this regard. EQ In the treble range, the headphones deliver transparency and detail resolution that gives the sound a brilliant that can only really be found in the high-end price range. Percussive details or small echoes you’ve not heard before can be discovered with glee here. In addition, the HD 660 S certainly shows the limits of a production. Room, Dynamics, Levels 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 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. I do feel that these headphones are distinct, however, each with their strengths and weaknesses. I have a minor gripe though as I think Sennheiser’s changes might not go far enough. With all the advantages and disadvantages considered, I can’t say it’s a better headphone than the other two – but if you factor in the cost differences vs. your own preferences, you should be able to draw a conclusion as to which suits you the most.

Specifications

Maybe Sennheiser would suggest that you can drive this headphone directly out of a smartphone, but I consider it an April’s Fools Day joke. This headphone need the cleanest possible amplification and, of course, a dedicated one. I’ve managed excellent results with an Audio GD Master 9, and also with a HeadAmp Pico Power, and even with the ordinary Pico. The headphone simply comes alive, the dynamics raises your pulse, it’s a completely different story with dedicated amplification. 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. Hm. Well they sort of state that it's a new design, but I'm betting that's a bit of poetic license—the HD 700 is a relatively new design. Thing is, impedance and phase measurements are almost identical. Anyway, what is really important is that sonically HD 660S is quite different from the HD 700, which for me is a good thing.

Where my two-decade old HD 580 Precisions sound lean and detailed, if slightly distant, the HD 660 S bring the music far closer. The bass still rolls off steeply below 40hz, but there’s now enough control and depth to do justice to bassy dance and electronica without resorting to bumping up the bass with EQ, and the mid-range has dramatically more meat on its bones. The treble remains smooth and delicate, even if it does seem more recessed as a result, and the overall sound signature is remarkably likeable across a wide range of musical genres. In this, and the following series of photos, the HD 600 is at left, the HD 650 at center, and the HD 660S is to the right.

Everything else is left at default, the master is usually brought at least at -7dB to avoid clipping. The uild quality includes mostly plastic, Sennheiser HD660S has some other materials that are not plastic, like for example the drivers, or the grills on the drivers / the padding, but this shouldn't be taken negatively, since there are plastics that can resist to extreme amounts of weight and pressure. Buy the Sennheiser HD 660S at headphones.com at the best price, and its the best return-policy available. In any case, if you like a slower smoother presentation, I think you’d better keep the HD 650 because it does this better.