TechAudioHeadphonesSennheiser HD 660S2 review: open-back headphones go big on bassIf you’re looking for open-backed headphones with big bass then Sennheiser’s second-gen HD 660S are well worth a lookWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.(Image credit: Sennheiser)T3 VerdictThere’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connectionsReasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapterWhy you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
TechAudioHeadphonesSennheiser HD 660S2 review: open-back headphones go big on bassIf you’re looking for open-backed headphones with big bass then Sennheiser’s second-gen HD 660S are well worth a lookWhen you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.(Image credit: Sennheiser)T3 VerdictThere’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connectionsReasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapterWhy you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
If you’re looking for open-backed headphones with big bass then Sennheiser’s second-gen HD 660S are well worth a look
When you purchase through links on our site, we may earn an affiliate commission.Here’s how it works.
(Image credit: Sennheiser)T3 VerdictThere’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connectionsReasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapter
(Image credit: Sennheiser)
(Image credit: Sennheiser)
T3 VerdictThere’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connectionsReasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapter
T3 VerdictThere’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.
T3 Verdict
There’s ‘unfashionable’ and then there’s wired headphones. But where outright performance in nearly every meaningful audio department is concerned, the Sennheiser HD 660S2 have plenty to recommend them - as long as your source of music is up to the task, that is.
Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connectionsReasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapter
Reasons to buy+Properly made, comfortable and durable+Burly, spacious and informative sound+Balanced or unbalanced connections
Properly made, comfortable and durable
Burly, spacious and informative sound
Balanced or unbalanced connections
Reasons to avoid-Treble sounds are slightly inhibited-Not fans of inferior sources-Awkward 6.3mm-3.5mm adapter
Treble sounds are slightly inhibited
Not fans of inferior sources
Awkward 6.3mm-3.5mm adapter
Why you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
Why you can trust T3Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you.Find out more about how we test.
The section of Sennheiser’s product portfolio that’s (probably) headed ‘people who take listening very seriously indeed’ is pretty extensive - and with the arrival of these new HD 660S2 wired open-backed over-ear headphones, it gets its latest update.
‘Wired’ and ‘open-backed’ both denote serious (and solitary) listening, of course - but Sennheiser is promising a laid-back experience to go along with all the ‘precision’ and ‘control’ it always aims for with its higher-end products.
So are the compromises you’ll need to make in order to accommodate such an uncompromising pair of headphones worth it in the end? And do the Sennheiser HD 660S2 earn a spot in thebest wired headphonesof 2023?
Sennheiser HD 660S2: Price & Availability
(Image credit: Future)
(Image credit: Future)
The Sennheiser HD 660S2 are on sale now, and in the United Kingdom they’re priced at £499. In America you’ll need to part with $599 to secure a pair, while in Australia they sell for AU$949.
This is, obviously, quite a lot of money for a pair of wired headphones with none of the frills or extended functionality we’ve lately come to expect from ourbest over-ear headphones.
And yet the HD 660S2 are not without competition - the likes of Audio Technica and Grado, to name just two deeply credible brands, have similarly specified and priced alternatives with which to tempt you.
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Sennheiser HD 660S2 review: What’s new?
(Image credit: Future)
(Image credit: Future)
It would be interesting to know how many people who heard the original HD 660S found them to be in any way unsettling to listen to. Because for the HD 660S2, Sennheiser is promising a more ‘intimate, relaxed’ sound - which is all well and good, but could conceivably be seen as addressing a problem that didn’t really exist.
This is an open-back pair of headphones, of course, almost as happy to leak sound outwards from the back of the earcups as it is to direct it to your ears. There is a 38mm full-range dynamic driver inside each earcup, with a very light aluminium voice-coil attached for rapid transient response. A vented magnet system seeks to minimise distortion.
Each of the HD 660S2 headphones is physically wired, using Sennheiser’s familiar two-pin connections. There are two 1.8m cables in the package - one has a 6.3mm unbalanced termination, the other a 4.4mm balanced alternative. Sennheiser also provides an unwieldy and inelegant 6.3mm-to-3.5mm adapter, which takes the overall cable length to comfortably over 2m.
Sennheiser HD 660S2 review: Performance
(Image credit: Future)
(Image credit: Future)
The very first thing that’s worth noting about the Sennheiser HD 660S2 is how intolerant they are of inferior sources of music - in its own way it’s almost admirable. Plug them directly into a MacBook Pro, for example, and the resulting sound is far from special.
(Image credit: Future)
(Image credit: Future)
The midrange is equally detailed, and vocalists of all types sound characterful and eloquent as a result. Again, the leading edges of individual sounds are cleanly described, and the integration with the frequency information above and below the midrange is smoothly achieved. One of the acknowledged advantages of the open-backed configuration is the relative spaciousness of presentation it allows, and these Sennheiser headphones certainly generate a large, well-defined and easy-to-follow soundstage. There’s more than enough breathing space available for each element of a recording to fully express itself, and plenty of room at the front of the stage for singers to take the spotlight.
The attention to detail these headphones exhibit easily extends to the small harmonic variations apparent in, say, a solo piano piece - and the HD 660S2 are fully attentive to transient activity that may be occurring even at the very edges or the very back of the soundstage. Where the big dynamic shifts are concerned, as when the symphony orchestra piles into that final crescendo, for example, the Sennheiser are barrel-chested enough to put significant distance between the quietest and the loudest moments.
At the top of the frequency range, though, there’s not quite as much positivity. Treble sounds are no less detailed than all the other frequency information the HD 660S2 serve up - but there’s a mild-but-definite lack of confidence and certainty to the top-end reproduction here. Treble seems a little rolled off, a little circumspect when compared to the rest of the sound - and as a result the Sennheiser don’t sound quite as clean or as clear as they otherwise would. Where the midrange communicates freely, and the bottom of the frequency range displays great assurance too, the top-end is circumspect - its tonality is a little more coloured than the rest of the information, and the overall unity of the HD 660S2 is compromised just a little as a result.
Sennheiser HD 660S2 review: Design & Usability
(Image credit: Future)
(Image credit: Future)
Nothing about the way the HD 660S2 are designed is going to startle you - they are designed, fundamentally, to look like a pair of headphones. And nothing about the way they’re built or finished will come as much of a surprise, either - this is a pair of Sennheisers, designed in Germany and made in Ireland, and they’re put together with obvious care.
The velour earpads are on the narrow side - but should be fine for anyone who doesn’t have very generously sized ears. The ear-cushions are on the soft side - but they don’t heat up especially quickly and stay comfortable for hours on end. The fabric-covered padding on the inside of the headband is equally pliant - and it’s equally comfortable too, with a nicely judged cutaway in the ‘fontanelle’ area. The clamping force is quite significant - but an all-in weight of 260g and an expertly judged hanger arrangement means the HD 600S2 are no kind of burden to wear.
There’s nothing especially luxurious about them, mind you - aside from the velour and the nicely tactile perforated metal covering the outside of the earcups, the Sennheiser are almost entirely plastic. But they look and feel pretty good, and the branding they carry manages to be discreet and yet quite assertive at the same time.
As far as ‘usability’ is concerned, passive wired headphones are about as straightforward and focused as a product can be. Once you know which of the three cable terminations you need in order to plug into your source of music (and have plugged it in), put the headphones on and press ‘play’.
Sennheiser HD 660S2 review: Verdict
(Image credit: Future)
(Image credit: Future)
The accommodations you’ll have to make with the Sennheiser HD 660S2 are few, but significant.
After that, though, the news is all good - so if you want a big, robust and opulently detailed sound from light, comfortable and properly constructed headphones, you need to give the Sennheiser HD 660S2 your complete attention.
Also consider
Yes, they’re a little more expensive than the Sennheiser HD 660S2 - but Audio-Technica’s splendid ATH-WP900 are well worth looking into. Not only do they sound expansive and detailed, with the sort of midrange fidelity in particular that could make a strong listener weak, but thanks to their ‘flame maple’ finish they’re classy lookers where the Sennheiser are profoundly functional.
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Today’s best Sennheiser HD660 S2 and Audio-Technica ATH-WP900 dealsSennheiser HD660 S2$440ViewSee all pricesAudio-Technica ATH-WP900$650ViewSee all pricesWe check over 250 million products every day for the best prices
Today’s best Sennheiser HD660 S2 and Audio-Technica ATH-WP900 dealsSennheiser HD660 S2$440ViewSee all pricesAudio-Technica ATH-WP900$650ViewSee all pricesWe check over 250 million products every day for the best prices
Today’s best Sennheiser HD660 S2 and Audio-Technica ATH-WP900 deals
Sennheiser HD660 S2$440ViewSee all pricesAudio-Technica ATH-WP900$650ViewSee all prices
Sennheiser HD660 S2$440ViewSee all prices
Sennheiser HD660 S2$440ViewSee all prices
Sennheiser HD660 S2
Sennheiser HD660 S2
$440View
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Audio-Technica ATH-WP900$650ViewSee all prices
Audio-Technica ATH-WP900$650ViewSee all prices
Audio-Technica ATH-WP900
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