Description
The Sennheiser HD 660S 2 headphones take the performance of its predecessors, the HD 650 and HD 600, to the next level with its supernatural speed and effortless instrument reproduction, even to the ends of the frequency range. The natural, warm sound and extended sub-bass make it an ideal choice for audiophiles.
Enjoy the Sennheiser Sound
By using a brand-new transducer and a specially ventilated driver unit, the Sennheiser HD 660S 2 headphones are able to provide audiophiles with a sound that’s perfectly suited for reproducing complex and intricate recordings with confidence. It’s sharp, and detailed and maintains the engaging and dynamic qualities that make music enjoyable. The 38mm diaphragm is agile thanks to the aluminium voice coil, allowing for precise tonal and spatial characteristics to be communicated through ultra-quick fidelity.Meshes with Your Music
The HD 660S 2 has a steel mesh that’s impressive in design and performance. It completes the ventilated driver, which controls the air displacement consistently to minimise turbulence. Consequently, the diaphragm moves freely, allowing the music to be heard in its purest form, with a perfect balance of authenticity and expression. The steel composition enables much tighter production tolerances, resulting in consistent characteristics of every headphone produced. When combined with the open-back earcups, the sound produced by each transducer is unrestricted, mimicking the natural soundstage.Matched for Perfection
Each unit of the Sennheiser HD 660S 2 has undergone a matching process to pair the transducer with its counterpart on the opposite channel. These processes have very precise tolerances, and when combined with automated assembly, they ensure top-notch quality throughout.
Designed For Durability & Acoustics
The materials used to design the HD 660S 2 are lightweight and carefully chosen to not affect the acoustics of the system, while still maintaining the durability needed for daily, extended use.Connect to Any Source
The HD 660S 2 comes with multiple 9.8 feet /3m-long cables in the box. The ¼-inch / 6.3mm stereo connector is the standard plug for audiophiles and can be used with various devices such as headphone amplifiers, A/V receivers, digital audio players, and more. The 4.4mm balanced connector is designed for newer balanced output devices such as headphone amplifiers and digital audio players and provides a more stable connection over time.Transducer principle: dynamic, open
Transducer size: 38 mm
Frequency response: 8 – 41,500 Hz
Impedance: 300 Ω
Sound pressure level (SPL): 104 dB (1 kHz, 1 Vrms)
Total harmonic distortion (THD): <0.04% (1 kHz, 100 dB)
Ear coupling: Over-Ear
Weight: 260g
Adapter: 6.3 mm (1⁄4 inch) to 3.5 mm
Connector: 6.3 mm (1⁄4 inch) jack plug, 4.4 mm balanced plug
Cable length: 1.8m
Country of origin: Ireland
Magnetic field: 4.5mT
What's included
HD 660S2 headphones
6.3 mm cable (1.8 m), 4.4 mm cable (1.8 m)
6.3mm to 3.5mm adapter
Carry pouch
Warranty Period: 2 Years from the date of Invoice
Covered: Manufacturing Defects Only
Website: https://en-in.sennheiser.com/service-support-contact-service-centers-in-india
Contact No: 1800 22 36 32
Email Id: in-info@sennheiser.com
Sennheiser is a well-known brand in the audio industry. They offer a wide range of products catering to both audiophiles and casual listeners. Their products include open back and closed back audiophile headphones, in-ear monitors, ANC headphones, and true wireless earbuds. They are known for their exceptional sound quality and durability. Whether you're a professional musician or just a music enthusiast, Sennheiser has something for everyone.
H660S2 is very well built transducer, it's quite clampy out of the box. The clamps can be eased but stretch softly over the metal band on both side.
Sound: music is warm with mids forward. Spiciness in the treble is not noticed. Bass is also subdued.
Note: My previous headphone are 560s, Sundara, Eligia and Clears.
Comparison:
With 560s: the 560s is v shaped compared to 660s2. Mids/vocals sound so good on 660s2. But the sub bass, mid bass, highs sound bit better on 560s. 660s2 suits clasical music while 560s suits rock, electronic and pop music. 560s also tend to distort with volume and eq, 660s2 doesn't sweat with volume and eq.
With focal clear: the focal clear is best in all genre no competition but vocals are slightly prefered on 660s2
With Sundara: Sundara sound very thin when compared but excels in details and soundstage.
Overall 660S2 or any of the 6X0 series headset are must for audiophiles. This headset sings with right vocal based tracks.

Sounds very enjoyable and open and also has good imaging and instrument separation and definition to the various components of music is great. More clarity than HD 650 and also warmer but crispy sounding. I have the ifi zen stack but I like it more with just the zen dac v2 balanced output. Great headphone under 30k if you like warm sound with vocal intimacy and details of instruments.
You will enjoy the music as these sound good but little tight fit heavy when compared to competition like Sony MDR MV1 (which I owned already) . It's good looking when we compare it to Sony ones but only problem for me is it's tight fitting and I found little heavy for long listening, I can't bear these or even sony more then 40 mintues max in one go. Price could also be little better. But it's worthy one if you want to enjoy music at its best at stage live performance rather then in your head like closed back. One of the best ones in open back but again little tight fit and heavy for me.
Thank you for your review of the Sennheiser HD 660S2 Open Back Headphones. We appreciate your feedback and are glad to hear that you are enjoying the sound quality. We apologize for any discomfort caused by the tight fit and weight of the headphones. Thank you for choosing Sennheiser, The Audio Store and happy listening!

Description
The Sennheiser HD 660S 2 headphones take the performance of its predecessors, the HD 650 and HD 600, to the next level with its supernatural speed and effortless instrument reproduction, even to the ends of the frequency range. The natural, warm sound and extended sub-bass make it an ideal choice for audiophiles.
Enjoy the Sennheiser Sound
By using a brand-new transducer and a specially ventilated driver unit, the Sennheiser HD 660S 2 headphones are able to provide audiophiles with a sound that’s perfectly suited for reproducing complex and intricate recordings with confidence. It’s sharp, and detailed and maintains the engaging and dynamic qualities that make music enjoyable. The 38mm diaphragm is agile thanks to the aluminium voice coil, allowing for precise tonal and spatial characteristics to be communicated through ultra-quick fidelity.Meshes with Your Music
The HD 660S 2 has a steel mesh that’s impressive in design and performance. It completes the ventilated driver, which controls the air displacement consistently to minimise turbulence. Consequently, the diaphragm moves freely, allowing the music to be heard in its purest form, with a perfect balance of authenticity and expression. The steel composition enables much tighter production tolerances, resulting in consistent characteristics of every headphone produced. When combined with the open-back earcups, the sound produced by each transducer is unrestricted, mimicking the natural soundstage.Matched for Perfection
Each unit of the Sennheiser HD 660S 2 has undergone a matching process to pair the transducer with its counterpart on the opposite channel. These processes have very precise tolerances, and when combined with automated assembly, they ensure top-notch quality throughout.
Designed For Durability & Acoustics
The materials used to design the HD 660S 2 are lightweight and carefully chosen to not affect the acoustics of the system, while still maintaining the durability needed for daily, extended use.Connect to Any Source
The HD 660S 2 comes with multiple 9.8 feet /3m-long cables in the box. The ¼-inch / 6.3mm stereo connector is the standard plug for audiophiles and can be used with various devices such as headphone amplifiers, A/V receivers, digital audio players, and more. The 4.4mm balanced connector is designed for newer balanced output devices such as headphone amplifiers and digital audio players and provides a more stable connection over time.Transducer principle: dynamic, open
Transducer size: 38 mm
Frequency response: 8 – 41,500 Hz
Impedance: 300 Ω
Sound pressure level (SPL): 104 dB (1 kHz, 1 Vrms)
Total harmonic distortion (THD): <0.04% (1 kHz, 100 dB)
Ear coupling: Over-Ear
Weight: 260g
Adapter: 6.3 mm (1⁄4 inch) to 3.5 mm
Connector: 6.3 mm (1⁄4 inch) jack plug, 4.4 mm balanced plug
Cable length: 1.8m
Country of origin: Ireland
Magnetic field: 4.5mT
What's included
HD 660S2 headphones
6.3 mm cable (1.8 m), 4.4 mm cable (1.8 m)
6.3mm to 3.5mm adapter
Carry pouch
Warranty Period: 2 Years from the date of Invoice
Covered: Manufacturing Defects Only
Website: https://en-in.sennheiser.com/service-support-contact-service-centers-in-india
Contact No: 1800 22 36 32
Email Id: in-info@sennheiser.com
Sennheiser is a well-known brand in the audio industry. They offer a wide range of products catering to both audiophiles and casual listeners. Their products include open back and closed back audiophile headphones, in-ear monitors, ANC headphones, and true wireless earbuds. They are known for their exceptional sound quality and durability. Whether you're a professional musician or just a music enthusiast, Sennheiser has something for everyone.
H660S2 is very well built transducer, it's quite clampy out of the box. The clamps can be eased but stretch softly over the metal band on both side.
Sound: music is warm with mids forward. Spiciness in the treble is not noticed. Bass is also subdued.
Note: My previous headphone are 560s, Sundara, Eligia and Clears.
Comparison:
With 560s: the 560s is v shaped compared to 660s2. Mids/vocals sound so good on 660s2. But the sub bass, mid bass, highs sound bit better on 560s. 660s2 suits clasical music while 560s suits rock, electronic and pop music. 560s also tend to distort with volume and eq, 660s2 doesn't sweat with volume and eq.
With focal clear: the focal clear is best in all genre no competition but vocals are slightly prefered on 660s2
With Sundara: Sundara sound very thin when compared but excels in details and soundstage.
Overall 660S2 or any of the 6X0 series headset are must for audiophiles. This headset sings with right vocal based tracks.

Sounds very enjoyable and open and also has good imaging and instrument separation and definition to the various components of music is great. More clarity than HD 650 and also warmer but crispy sounding. I have the ifi zen stack but I like it more with just the zen dac v2 balanced output. Great headphone under 30k if you like warm sound with vocal intimacy and details of instruments.
You will enjoy the music as these sound good but little tight fit heavy when compared to competition like Sony MDR MV1 (which I owned already) . It's good looking when we compare it to Sony ones but only problem for me is it's tight fitting and I found little heavy for long listening, I can't bear these or even sony more then 40 mintues max in one go. Price could also be little better. But it's worthy one if you want to enjoy music at its best at stage live performance rather then in your head like closed back. One of the best ones in open back but again little tight fit and heavy for me.
Thank you for your review of the Sennheiser HD 660S2 Open Back Headphones. We appreciate your feedback and are glad to hear that you are enjoying the sound quality. We apologize for any discomfort caused by the tight fit and weight of the headphones. Thank you for choosing Sennheiser, The Audio Store and happy listening!
You may also like
OUR HONEST REVIEWS FROM THE CO-FOUNDERS & AUDIOPHILES
View allTRUSTED BY OVER 35K+ MUSIC ENTHUSIAST
Let customers speak for us
from 4738 reviews
From Blon bl2 to BGVP DN2
The jump on dunu was really worth it
Almost every genre songs this IEM drive at another level of dept n separation
Only flaw i could pin point some jpop heavy electric or high pinch voice of singers was little intolerable but other than it skillet and every other genre it nail it..
Accesories are another level really feel like worth the price and best customer care...
Tried every format from flac mqa to dsd . movies or series or anime . this earphone r all in one.
Bass timing silent timing Treble timing is all so perfectly tune (tried on LGV50)

If you are looking for a pair of headphones that would be your end game on a budget, then look no further, Edition XS is the way to go.
I have been using these for about 2 years and finally I can say, these cans a robust, dynamic and neutral to slightly bright.
But it also packs a punchy bass and has a good soundstage.
All you need is a pair of Edition XS and further you can keep leveling up the sound quality by upgrading cables to balanced ones, getting good DAC/AMPS and also modding the cans with new filters and grill.

Pros:
1. Sound is excellent for the price. I would say moondrop chu level sound quality. It follows the harman target with a little but turned down treble. Many people find the harman target a bit harsh at the top end. But this solves the issue.
2. I never had connectivity issues. Pairing was easy. As soon as I bring out the earbuds from the case, the buds automatically connects to my android phone.
Cons
1. App could be better. Obviously the app and other functionality won't be at the level of other mainstream tws like bose, samsung etc.
2. The fit. As someone who mostly uses wired iems. The tws does not feel as comfortable as the iems. For my ears, it's only comfortable for an hour or so. After that, it gets really uncomfortable.

I have been through some online videos/reviews before this purchase. My shortlist were, Moondrop Chu II, KZ Castor Pro, Wan'er SG. Audio Store was kind enough to provide demo of these to compare. Also Mr. Pritam shared valuable inputs on differences between my selected comparisons.
Very happy with the Tangzu Wan'er SG's output, everytime I listen to some of my old fav bolly songs it generates smile. Guess using it day by day increasing some sort of details or maybe I am getting use to. Best for listening for longer duration without fatigue. Bassheads may find it irrelevant to their taste. Over-all best Balanced tune IEM I must say which has some spark and doesn't feel boaring.

In the realm of audiophile excellence, where sound transcends mere listening and becomes an immersive journey, the Roseselsa Distant Mountain headphones emerge as a beacon of luxury and precision. Marrying vintage aesthetics with cutting-edge technology, these headphones offer a sublime auditory experience that caters to the most discerning of listeners.
Design and Build Quality
The Distant Mountain captivates with its retro-inspired design, reminiscent of the golden age of personal audio. The headband, crafted from solid stainless steel and adorned with genuine lambskin, ensures both durability and unparalleled comfort. The coaxial CNC-machined body exudes a high-gloss finish, presenting an extraordinary high-end texture that is both versatile and fashionable. 
Sound Performance
At the heart of the Distant Mountain lies an innovative 40mm composite topological diaphragm. This redesigned dome and corrugated ring deliver crisp, transparent treble and profound, surging bass. Enhanced by neodymium super magnets and an acoustic structure dedicated to small-sized headsets, the Distant Mountain presents richer sound details and a more natural treble extension, immersing the listener in melodious music. 
Comfort and Usability
The sponge ear pads are designed with both softness and breathability in mind, ensuring prolonged listening sessions remain comfortable. The headband supports fine length adjustments, with clearly visible scales to alleviate any concerns about symmetry. The inclusion of a stranded-free 5N single crystal copper IEM cable, coupled with a detachable MMCX design, offers high playability and customization for the user. 
Conclusion
The Roseselsa Distant Mountain is a testament to superb build quality and exceptional sound performance. Its unique tuning direction, reminiscent of high-fidelity in-ear monitors, combined with its luxurious design, makes it a standout choice for audiophiles seeking both style and substance. While it may require amplification to truly shine and could benefit from thicker earpads for optimal comfort, its value proposition remains compelling. For those who appreciate a blend of retro aesthetics and modern audio excellence, the Distant Mountain is an unrivaled choice. 
In the grand symphony of high-fidelity audio equipment, the Roseselsa Distant Mountain plays its notes , offering a professional and luxurious listening experience that is both nostalgic and forward-thinking.

I was not expecting much but this IEM sounds really good. If feels like a much more expensive IEM. The convenience thanks to the USB-C connection is great. I am able to use it on my phone, ipad and laptop. Gonna get some and gift some friends. This is a great gifting IEM / starter IEM !!!
I love the compatibility and the bill quality of the AUDIOCULAR d07, it works well with my samsung m53, . I also liked that u provide a case along with it , 😉

Good Sound Quality. Bass Treble Mid Too God Under 2k Price, Lookwise Good & Ear Fit & Gaming Experience To Good. & clear Sound Sense.
Earphone Case Too Good 👍 I like it.
Fast Delivery in 2 day delivery In My Address.

This is a solid technical iem with a very neutral tuning. Its a keeper iem for those who already have a collection of somewhat coluored or tasteful sounding iems under 10k .

Increased the volume as well as clarity of audio.
Thanks to the audio store for a quick delivery

This was my first experience with The Audiostore and it was welcoming. Happy with the service provided and customised suggestions as per need. Looking forward to buy next one. Thanks.

Awesome work

Fantastic easy to use dongel dac by Shanling. Build quality is also 👌. For a budget music lover this is a value for money. TAS keep providing such affordable quality product to us always...👍

Sparkling music, enhance volume and gives extra wide sound instrument but some time later connection gone if audio is not play

The CD player works as advertised. The single ended headphone jack has decent output, able to drive IEMs at a loud volume level. The coaxial output also works with a 3.5mm male to coaxial cable hooked to a pre-amp. Sound signature is unolocured in the territory of neutral to slightly bright neutral and corresponds well with recording and mastering of records. Worth the money imo.