The Sennheiser HD 660 S Headphones: An Audiophile's Dream Come True

Published on May 11, 2023, 4:20 p.m.

As an audiophile, finding the perfect pair of headphones can feel like an endless quest filled with peril. You journey far and wide, enduring blistered ears and depleted wallets, searching desperately for that mythical sonic holy grail. Just when all hope seems lost, a beam of light pierces the darkness - the Sennheiser HD 660 S. Could these open-backed German engineered beauties be the long-awaited answer to an audiophile’s prayers? Let’s discuss.

 Sennheiser HD 660 S Headphone

Overview

The Sennheiser HD 660 S Headphone are open-back dynamic hi-fi headphones first released in 2017. Building upon the legendary HD 600 and HD 650 models, the Sennheiser HD 660 S Headphone utilize new specially designed transducers to deliver breathtakingly natural and accurate sound reproduction. With an accessible 150 ohm impedance, ergonomic design and versatile connectivity options, could the Sennheiser HD 660 S Headphone be the ultimate all-purpose audiophile headphone?

 Sennheiser HD 660 S Headphone

Design

Sporting Sennheiser’s iconic open-back look, the Sennheiser HD 660 S Headphone are as stylish as they are comfortable. The lightweight construction and plush padding allow for fatigue-free listening over extended sessions. No more sore ears or aching headbands! An open-back design does mean sound leakage, so keep that in mind. The included cables are long enough to provide plenty of slack, letting you rock out without accidentally yanking your device off the desk.

Acoustic Design:

The HD 660 S’s open-back earcups and innovative steel mesh drive unit work in harmony to create an unparalleled acoustic experience. The steel mesh, while visually striking, serves a crucial function in controlling air displacement and reducing turbulence. This precision engineering ensures that the diaphragm’s movement is pure and unimpeded, allowing the music to flow freely and naturally. The open-back design further enhances this effect, enabling sound waves to expand without constraint, just as they would in a live performance.

Reference-Class Open-Back Design:

The Sennheiser HD 660 S’s open-back design is not merely an aesthetic choice; it’s a fundamental element in its sonic signature. By allowing air to flow freely through the earcups, these headphones create a remarkably spacious and natural soundstage. Instruments and vocals are presented with a sense of depth and airiness that closed-back headphones often struggle to achieve. This open design also minimizes resonance and reflections, resulting in a cleaner, more transparent sound that audiophiles crave.

Sound Quality

Turn on your favorite sonic delicacy and prepare to be amazed. The Sennheiser HD 660 S Headphone produce astonishingly clear and detailed sound across the frequency spectrum. Crisp highs dance with delight, while punchy lows boom with joy. The midrange is lush and lifelike, making vocals dazzle and instruments sing. Closed-back models boast big bass but sacrifice soundstage - not so with the Sennheiser HD 660 S Headphone’s spacious open-back design. The imaging is holographic, allowing you to pinpoint sounds in a three-dimensional space. From jazz soloists to heavy metal shredders, nothing gets lost in the mix.

Driver Technology:

At the heart of the HD 660 S’s sonic prowess lies a meticulously engineered transducer designed to redefine your audio experience. Its aluminum voice coil propels a 38mm diaphragm, resulting in a lightning-fast response that effortlessly reproduces the most intricate details and nuances in your music. This agility ensures exceptional impulse fidelity, allowing the headphones to accurately convey the tonal and spatial characteristics of each instrument and vocal.

150 Ohm Impedance:

The HD 660 S’s 150-ohm impedance makes it compatible with a wide range of audio devices, including dedicated headphone amplifiers, digital audio players, and even some smartphones and tablets. This flexibility allows you to enjoy your music with exceptional fidelity regardless of your preferred listening setup. While the headphones can be driven directly from many devices, they truly shine when paired with a high-quality headphone amplifier, which can unlock their full potential and deliver even greater detail and dynamics.

Improved Transducer Technology:

Sennheiser’s commitment to innovation is evident in the HD 660 S’s all-new transducers. These drivers have been meticulously engineered to deliver lower harmonic distortion, resulting in a more faithful reproduction of the original recording. The transducers’ exceptional accuracy and transparency allow you to hear every nuance and detail in your music, from the subtle inflections in a vocalist’s voice to the delicate reverberations of a plucked string.

Hand-Selected Transducers:

To ensure the utmost precision and consistency, Sennheiser hand-selects the transducers for each pair of HD 660 S headphones. This meticulous process guarantees that the left and right drivers are perfectly matched, resulting in impeccable stereo imaging and a balanced soundstage. You’ll be able to pinpoint the exact location of each instrument and vocal in the mix, creating a truly immersive listening experience.

Hi-Res Audio Certified:

The Sennheiser HD 660 S proudly wears the Hi-Res Audio badge, signifying its ability to reproduce high-resolution audio files with stunning fidelity. This certification ensures that you can experience the full depth and detail of your music, as the artists and engineers intended. Whether you’re listening to lossless FLAC files or streaming high-quality audio from Tidal or Qobuz, the HD 660 S will deliver an unparalleled listening experience.

Low Harmonic Distortion:

Harmonic distortion is the enemy of audio fidelity, introducing unwanted artifacts and muddying the sound. The HD 660 S’s transducers are engineered to minimize harmonic distortion, resulting in a remarkably clean and accurate sound reproduction. You’ll hear your music with exceptional clarity and transparency, free from the distortions that can plague lesser headphones.

 Sennheiser HD 660 S Headphone

Impedance and Connectivity:

With a 150-ohm impedance, the HD 660 S strikes a perfect balance between efficiency and performance. It can be easily driven by a variety of devices, from dedicated headphone amplifiers and AV receivers to digital audio players and even some mobile devices. This versatility ensures that you can enjoy your music with exceptional fidelity regardless of your preferred audio setup. The included cables, featuring both 6.35mm and 4.4mm Pentaconn connectors, further enhance the headphones’ adaptability, allowing you to connect to a wide range of audio sources with ease.

Para-aramid Reinforced Cables:

The HD 660 S comes with two detachable cables, both of which are reinforced with para-aramid, a high-strength synthetic fiber known for its durability and resistance to wear and tear. This ensures that the cables can withstand the rigors of daily use and maintain their signal integrity over time. The cables are also made with high-conductivity OFC (oxygen-free copper) to minimize signal loss and ensure the purest possible sound transmission.

Two Connection Cables and Adapter:

Sennheiser understands that audiophiles have diverse listening setups, so they’ve included two connection cables with the HD 660 S: a 6.35mm stereo plug cable for traditional headphone amplifiers and a 4.4mm Pentaconn balanced cable for balanced audio sources. A 6.35mm to 3.5mm adapter is also included, allowing you to connect the headphones to a wider range of devices, such as smartphones and laptops.

Use Cases:

Let the Sennheiser HD 660 S Headphone whisk you away to sonic paradise whether you’re:
- Blissfully reclining in your favorite armchair after a long day to relax with hi-res Mozart or Coltrane.
- Reveling in the immersive worlds of your favorite fantasy or sci-fi cinematic soundtracks.
- Mixing your magnum opus audiophile-quality music album or podcast with analytical precision.
- Competing in epic all-night multiplayer gaming battles where pinpoint audio localization gives you the winning edge.

Value:

While expensive for mainstream buyers, the Sennheiser HD 660 S HeadphoneS deliver a peerless audiophile experience that makes them a stellar value for serious listeners wanting exquisite German-engineered sound.

 Sennheiser HD 660 S Headphone

Conclusion

The Sennheiser HD 660 S Headphone deliver a world-class listening experience that makes your music shine. With stunning sound, great comfort and versatile connectivity, they are a top-tier open-back audiophile headphone. As long as you feed them proper quality sources, the Sennheiser HD 660 S Headphone will take your listening pleasure to heavenly heights. While not cheap, serious listeners will cherish the sublime musical magic these headphones conjure. The quest is over my audiophile brethren - in the Sennheiser HD 660 S Headphone, we have found audio nirvana.