{"product_id":"sennheiser-hd-660s2-wired-audiophile-headphones-natural-open-back","title":"Sennheiser HD 660S2 Wired Audiophile Headphones - Natural Open-Back","description":"\u003cp\u003eOur review of the Sennheiser HD 660S2 finds a pair of wired, over-ear headphones aimed squarely at listeners who prioritize natural, high-fidelity sound and extended comfort. The single biggest reason to consider them is the open-back design paired with 42mm transducers and an ultra-light aluminum voice coil, which deliver a spacious soundstage and exceptionally clear highs while still providing deep, controlled sub-bass that makes acoustic and orchestral music feel immediate and alive.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAudiophile open-back sound:\u003c\/strong\u003e The open-back design creates a wide, natural soundstage that helps complex mixes breathe and instruments sit in a realistic space.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e42mm transducers with aluminum voice coil:\u003c\/strong\u003e These drivers provide detailed highs and rich mids while keeping distortion low at moderate listening levels.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDeep controlled sub-bass:\u003c\/strong\u003e Frequency response reaching down to 27.5 Hz gives weight and clarity to low piano notes and bass drums without becoming boomy.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eComfort for long sessions:\u003c\/strong\u003e Breathable, plush ear cushions and an over-the-head fit reduce fatigue during extended listening or monitoring sessions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDetachable wired cable:\u003c\/strong\u003e Removable long cables add convenience for desktop systems and audio interfaces while keeping the headphones simple and reliable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePremium construction:\u003c\/strong\u003e Build quality from Germany and Ireland focuses on durable materials and an understated, elegant finish.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe HD 660S2 is best for audiophiles, home listeners, and music professionals who want an open, natural presentation for critical listening, mixing, and desktop enjoyment. Its clear mids and precise highs suit acoustic, classical, and vocal-forward material particularly well.\u003c\/p\u003e\n\u003cp\u003eThose who need noise isolation, a closed-back profile for portable use, or wireless convenience should look elsewhere, since the open-back wired design prioritizes soundstage and air over isolation and on-the-go practicality.\u003c\/p\u003e\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eExceptional clarity and natural presentation that reveal fine musical detail.\u003c\/li\u003e\n\u003cli\u003eComfortable plush ear cushions that support long listening sessions without fatigue.\u003c\/li\u003e\n\u003cli\u003ePowerful yet controlled low-end reach that handles notes down to 27.5 Hz with precision.\u003c\/li\u003e\n\u003cli\u003eDetachable cable and solid construction for longevity and flexible use at a desk or with audio equipment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eOpen-back design offers little isolation and is unsuitable for noisy environments or portable use.\u003c\/li\u003e\n\u003cli\u003eSome buyers may find the value proposition mixed compared with other models in the same price area.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eDesign\u003c\/td\u003e\n\u003ctd\u003eOpen-back, over-ear\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTransducers\u003c\/td\u003e\n\u003ctd\u003e42 mm with ultra-light aluminum voice coil\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLow frequency response\u003c\/td\u003e\n\u003ctd\u003eDown to 27.5 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh frequency response\u003c\/td\u003e\n\u003ctd\u003eUp to 4560 Hz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCable\u003c\/td\u003e\n\u003ctd\u003eDetachable wired cable(s)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eComfort\u003c\/td\u003e\n\u003ctd\u003eBreathable plush ear cushions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eManufacturing\u003c\/td\u003e\n\u003ctd\u003eCrafted in Germany and Ireland\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe Sennheiser HD 660S2 is a refined wired headphone for listeners who value an open, natural soundstage, detailed highs, and a controlled low end. Its comfort and build quality make it a strong choice for home audiophiles and professionals working at a desk, and it represents good value for anyone prioritizing clarity and musicality over isolation or wireless features.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these headphones closed or open-back?\u003c\/strong\u003e\u003cbr\u003eThey are open-back, designed to deliver a spacious soundstage rather than isolate from outside noise.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use these with a phone or portable player?\u003c\/strong\u003e\u003cbr\u003eYes, but they are wired and perform best with a quality source or headphone amplifier; they do not provide passive isolation for noisy environments.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre they comfortable for long sessions?\u003c\/strong\u003e\u003cbr\u003eYes, the breathable plush ear cushions and over-head fit are intended for fatigueless listening during extended sessions.\u003c\/p\u003e","brand":"Sennheiser","offers":[{"title":"Default Title","offer_id":48749754187995,"sku":"B0BRT1ZN7Q","price":477.21,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/81xpWUthgjL._AC_SL1500.jpg?v=1778776815","url":"https:\/\/gearmusthave.com\/products\/sennheiser-hd-660s2-wired-audiophile-headphones-natural-open-back","provider":"GearMustHave","version":"1.0","type":"link"}