HD 660S

Sennheiser Star Rating

4.7 (21) Reviews

$ 499.95
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HD 660S – The perfect blend of power and control, the HD 660S is a powerhouse open-back headphone with the versatility to connect you to the deepest corners of your music collection.

»Sennheiser succeeds in creating a masterpiece with the HD 660S. The headphones deliver true audiophile sound quality that’s perfectly balanced when required.«
headphonecheck.com, kopfhoerer.de
»...there is something comforting and familiar about the HD 660S's bass presentation. It is a classic sound that is just "right".«
Enjoy The Music.com
»The 660S allowed the listener to be intimately involved with the music, pulling you into the soundstage itself, wrapping you up in the emotion of the performance.«
The Audiophile Man
»The HD 660S captured a fantastic amount of detail.«
SoundStage! Australia
»Open-backed home headphones which deliver tunes both old and new as if piped fresh from the studio, with music flowing effortless and free.«
Sound+Image (print; Awards 2018)

A Direct Connection To Your Music

Known for their engaging signatures and liquid-smooth response, HD 660S predecessors HD 650 and HD 600 shattered performance barriers in the audiophile headphone category. The HD 660S transcends the best of that storied DNA with supernatural speed and effortless instrument reproduction—even at the bookends of the frequency spectrum. Utilizing an all-new transducer and specially ventilated drive unit, the HD 660S delivers the revealing, tack-sharp detail audiophiles demand without sacrificing the engaging dynamics that make music so enjoyable.

A Direct Connection To Your Music

From Our Ears To Yours

In just one listen you will understand why the HD 660S is so special. Thousands of listening sessions later its purpose is even clearer. What you hear each and every time is the result of an open-back earcup mated to a new transducer tuned for the modern audiophile. Its speedy response is perfectly suited for reproducing those frequency-stretching recordings with confidence. Thanks to an aluminum voice coil, the 38mm diaphragm remains nimble for ultra-quick impulse fidelity across the board. This activation and rest behaviour unlocks the capability to communicate tonal and spatial characteristics precisely.

From Our Ears To Yours

Meshing Together

The steel mesh found on the HD 660S drive unit is interesting in design but most impressive when it comes to performance. It completes the ventilated driver, offering consistent control of air displacement to reduce turbulence. As a result, diaphragm travel is pure, letting the music—and only the music—shine in a perfect balance of integrity and expression. The steel composition allows for much tighter production tolerances, ultimately contributing to remarkably consistent characteristics of each HD 660S produced. When combined with the open-back earcups, the sound emanating from each transducer is completely free to expand, just as it would in nature.

Capability, Meet Versatility.

Today’s audiophile has more component choices than ever. We optimized the HD 660S for efficiency on a wider range of devices to accommodate the varying levels of power present in output amplification circuitry. At 150 ohms, the HD 660S is the perfect partner for dedicated amplifiers, A/V receivers, and audio interfaces alike—the magnet is more powerful than its predecessors, and thus easier to drive regardless of how your setup changes over time.

Capability, Meet Versatility.

Handled With Care

Every HD 660S we produce has experienced a matching regimen to mate each transducer from our Ireland manufacturing facility to its opposite-channel counterpart. These tolerances are extremely narrow and when bolstered by automated assembly processes, ensure that your HD 660S experience is consistent with those all over the globe. We designed it with thoughtful, lightweight materials invisible to the acoustical system without sacrificing the durability needed for daily, all-day use. With a never-ending supply of music to consume, we wanted every touch point to be soft, luxurious, and durable for those extended listening sessions.

Handled With Care

It’s All About Connection

We packed your HD 660S with a versatile set of essential cables, each one impedance-matched with ultra-low capacitance. The ¼-inch / 6.3mm stereo connector offers the audiophile-standard plug for connection to devices such as headphone amplifiers and A/V receivers, digital audio players, computer-based workstations, analog gear, and more. A balanced, 4.4mm connector opens a pathway to a newer generation of balanced output devices (headphone amplifiers, digital audio players, etc.) that embrace this compact plug’s superior stability over time. A balanced headphone setup offers an even lower noise floor with great dynamic range when connected to balanced source/amp circuit outputs. The listener will thus experience a wider soundstage, tightly controlled transients and impossibly-clear instrument separation. Each cable is 9.8 feet / 3m long to accommodate unencumbered listening on gear deep within your shelves, studio, or desktop, and a flexible adapter is included to reduce the 6.3mm to 3.5mm. An optional balanced cable (CH 650 S) is sold separately for simplified connection to 4-pin XLR jacks.

It’s All About Connection

Technical Data

  • Wearing style
    Headband
  • Color
    matte black
  • Frequency response (Headphones)
    9 – 41,500 Hz
  • Sound pressure level (SPL)
    104 dB
  • THD, total harmonic distortion
    < 0,04%
  • Contact pressure
    6.0 N ± 1 N
  • Ear coupling
    circumaural
  • Connector
    6.35 mm / 4.4 mm Pentaconn
  • Cable length
    3 m
  • Transducer principle
    Dynamic, open
  • Nominal impedance
    150 Ω
  • Weight w/o cable
    260 g
Reviews (21)
4.7 of 5 ★ ★ ★ ★
  • Anonymous
    Not applicable
    ★★★★★
    HD 800 S Junior: Or The Headphone The HD 700 Should Have Been

    At quick glance, the HD 660 S may look like a modified HD 650 with HD 700 drivers transplanted inside of it, but that is where the similarities end. The HD 660 S offers the low-level detail characteristics that make the HD 800 so highly coveted among TOTL- and kilobuck-seeking audiophiles but with the HD 600's naturalness. In other words, remove the treble peaks that plague the HD 700 and, to a lesser degree, the HD 800, and retain the resolution of the HD 800 and you have the HD 660 S. Sennheiser has been removing the HD 650 from their site, and that alone suggests they have deep confidence in this new mainstream audiophile flagship product. I concur without equivocation, as I can see the HD 660 S easily inheriting the HD 650's throne to become the new go-to headphone among the community at large. In addition, I could see many of those who were less than thrilled with the HD 800's clinical sound (slightly withdrawn upper midrange and slightly boosted mid treble) going in ravenous droves after the HD 660 S. I really had to grasp at straws to find something negative to comment about these, and the only thing I could state is perhaps the retro looks may seen worn out or uninspired, but I personally am fond of this more classic, understated Sennheiser look over the gaudy Cyberman-like, space-age vibe of the HD 800 and HD 700. This is your atypical all-arounder with heightened technical abilities. Fast or slow, brash Bon Jovi or binotonous Beethoven, Sennheiser nailed this release with world-class expertise. Arguably, you could not do any better $999 and below. Amped and unamped, the HD 660 S is a force to be reckoned with, well-deserving of and highly recommended for a spot in the headphone stables of audiophiles seasoned and budding.

    PRO:

    At quick glance, the HD 660 S may look like a modified HD 650 with HD 700 drivers transplanted inside of it, but that is where the similarities end. The HD 660 S offers the low-level detail characteristics that make the HD 800 so highly coveted among TOTL- and kilobuck-seeking audiophiles but with the HD 600's naturalness. In other words, remove the treble peaks that plague the HD 700 and, to a lesser degree, the HD 800, and retain the resolution of the HD 800 and you have the HD 660 S. Sennheiser has been removing the HD 650 from their site, and that alone suggests they have deep confidence in this new mainstream audiophile flagship product. I concur without equivocation, as I can see the HD 660 S easily inheriting the HD 650's throne to become the new go-to headphone among the community at large. In addition, I could see many of those who were less than thrilled with the HD 800's clinical sound (slightly withdrawn upper midrange and slightly boosted mid treble) going in ravenous droves after the HD 660 S.

    CON:

    I really had to grasp at straws to find something negative to comment about these, and the only thing I could state is perhaps the retro looks may seen worn out or uninspired, but I personally am fond of this more classic, understated Sennheiser look over the gaudy Cyberman-like, space-age vibe of the HD 800 and HD 700.

    BEST USES:

    This is your atypical all-arounder with heightened technical abilities. Fast or slow, brash Bon Jovi or binotonous Beethoven, Sennheiser nailed this release with world-class expertise. Arguably, you could not do any better $999 and below. Amped and unamped, the HD 660 S is a force to be reckoned with, well-deserving of and highly recommended for a spot in the headphone stables of audiophiles seasoned and budding.

    BOTTOM LINE:

    I would recommend this to a friend.

  • Jimmy
    ★★★★★
    I cannot wait for this headphone to drop

    Hopefully this will settle the 600-650 debate -- the answer will be to just get this headphone.

    PRO:

    Looks beautiful, probably sounds amazing too

    CON:

    Not yet released

    BEST USES:

    BOTTOM LINE:

    I would recommend this to a friend.

  • Eduardo M.
    Portugal
    ★★★★★
    HD 660 Heir to the meticulous commitment of quality sennheiser

    Sennheiser once again showing why experience is more than important. The best choice was to bring this new technology from its transducers into an oval design that was, is and will be for a long time one of the best ever drawn. An oval design that Sennheiser hit on the headphones Orpheus, in HD 580, HD 600 and HD 650, these headphones hit with a very well designed and timeless minimalist design, which until now few or no rival got to hit this line of drawings, it is not enough to only have the quality sound if the design is not good. This design also inherited good headphones as the line HD 500. Sennheiser showed in these headphones that she is following the new era but without losing classicism and high sound quality. Anyone who has doubts about the sound quality of any Sennheiser headphones, know that the engineers explained and hit the description of each product on this Website, because who better than them to explain their own creations. Sennheiser - Single sound signature. Feel the life that music wants to pass.

    PRO:

    Timeless Design; Internal and external quality and unmatched sennheiser sound signature; Compatibility.

    CON:

    none

    BEST USES:

    indoor environments due to open design; preferably listening with lossless audio and with an amplifier will ensure a better experience.

    BOTTOM LINE:

    I would recommend this to a friend.

Downloads

  • EU Declaration of Conformity
    • EU Declaration of Conformity HD 660 S (390 KB) Download

  • Instruction Manual
    • Instruction manual HD 660 S (6.3 MB) Download

      Version 07/2019

WARNING (for California residents only): This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects and other reproductive harm. For more information go to: www.p65warnings.ca.gov.