HD 660 S2 Hi-fi Open Back Dynamic Audiophile Headphones, Black

HD 660 S2 Hi-fi Open Back Dynamic Audiophile Headphones, Black

HD 660 S2 Hi-fi Open Back Dynamic Audiophile Headphones, Black

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Description & Specifications

Enjoy your music on a completely new level. An intimate, relaxed sound signature combines with outstanding precision and exceptional comfort and now, extended sub bass for a deeply moving experience. The extremely precise yet non-fatiguing sound of the HD 660S2 delivers even more impact with extended sub bass. With an optimized surround, transducer air flow, and coil our engineers doubled the sound pressure at the lowest octaves. You can feel the lowest note on the piano (27.5 Hz) or the kick of the bass drum (45-60 Hz) as if you were there. The relaxed tone and open-back design make this extremely comfortable headphone great for long sessions. With warm tuning, smooth treble, and strong bass, the standard-setter for extended listening is now the standard-setter for extended bass as well.


The HD 660S 2 is a high performance audio product, and requires an adapter to connect to your mobile phone. For an ultimate audio experience, the HD 660S 2 is best paired with a small DAC or suitable amplifier

  • Audiophile sound - The natural, relaxed, high-fidelity sound (8 Hz - 41,500 Hz) offers an intimate listening experience with great timbre and deep, accurate sub bass.
  • 42mm high-performance transducers - Steel mesh damping follows the driver’s geometry to control air displacement for precise sound
  • Vented magnet system - The magnetic yoke includes milled air vents for optimal ventilation to minimize distortion.
  • Aluminium voice coil - Specially developed ultra-light voice coil with 300-ohm impedance for excellent impulse response
  • Open-back earcups - Facilitate the natural expansion of sound waves for a hi-fidelity spacious soundstage.
  • Exceptional comfort - Open elliptical earcups provide breathability and luxuriously comfortable velour pads provide hours of fatigue-free listening.
  • Outstanding build quality - Designed in Germany, made in Ireland, each element is carefully selected to meet exacting standards
  • Detachable cables - Para-aramid reinforced cables with OFC copper ensure signal integrity and a very low handling noise.
  • Ergonomic design - The low total weight and ergonomic headband eliminate potential discomfort on top of the head.


The service policies and warranty statements on this page are relevant for all Sennheiser products and Sennheiser distributed brands. Sennheiser Electronic Corporation (referred to as SEC or Sennheiser for the duration of this document) warrants to the original purchaser that the product purchased will be free of defects related to manufacturing, parts, materials, and workmanship under normal and accepted use. Conditions under which the manufacturer's limited product warranty statement is no longer valid can be found below. Sennheiser offers a worldwide warranty on its products though it is strongly encouraged that all warranty returns be sent to the customer's local Sennheiser Authorized Service Center.

This limited product warranty is SEC's only warranty and the customer's only remedy concerning the product. All other representations, warranties or conditions, expressed or implied, written or oral, including but not limited to any warranties or guarantees of merchantability, fitness for a particular purpose, or non-infringement, are expressly excluded. As a result, except as set forth in the previous and following paragraphs, the product is sold "as-is" and the customer is assuming the entire risk as to the product's suitability to their needs, its quality and its performance.

Sennheiser Products: 2 Years

Refurbished Products: Carry the standard warranty**

** Refurbished product warranties are only valid when purchased from an authorized Sennheiser reseller.

At Sennheiser, we seek to excel in shaping such experiences each and every day. Since the inception of our company 75 years ago, we have become one of the world’s leading manufacturers of headphones, loudspeakers, microphones and wireless transmission systems.

Our Vision

Shaping the future of audio and creating unique sound experiences for customers is the aim that unites Sennheiser employees and partners worldwide.

Our History

Turning 75 years in 2020, we are looking forward to celebrating and looking back on a history of ideas, innovations, challenging projects and achievements.

Our Culture

As an international team we cherish our differences and unique qualities but share one thing: our passion for audio. This passion forms the basis of our company culture and defines our day-to-day working lives with our colleagues, with our partners and with our customers.

We Care

With our headquarters in Wennebostel, Germany where Sennheiser was founded, we remember our roots: We care about our impact on the world and take responsibility for our role as a leading company within the audio industry.

Do you have a question about one of our products? Would you like to know more about Sennheiser? Please don’t hesitate to contact us, you'll find the answers you want quickly. We look forward to receiving your message!

We provide free shipping with any and all orders purchased through SennheiserAU. Please be advised that our carrier may vary depending on your location. Please feel free to contact us for a list of supported carriers.

Domestic Shipping

The following shipping speeds and standards are applicable to all orders within Australia.

  • Free Standard Delivery (1-6 day shipping)
  • Handling Time – 1 Business day
International Shipping

We are currently not offering international shipping. We apologize for any inconvenience this may cause you. Rest assured that our team is working diligently to make our products available to you locally. Please contact us to find an authorized retailer near you.

Excluded Shipping Locations

Africa, Asia, Central America and Caribbean, Europe + UK, Middle East, North America, Oceania, South America, Southeast Asia, PO Box

The SennheiserAU eBay store offers a 30-day money-back guarantee on all products sold directly through SennheiserAU.

To request a refund, please contact us by opening a return request through eBay’s resolution center. You can find this page by navigating into your eBay purchase history and clicking the Request Return button.

Please be advised that every return is handled on a case to case basis. If you would like to learn more about your return eligibility, please contact us with your order number handy and we will be more than happy to assist you.