RANKING

Rank 49 out of 53 Summarized in this category Rankings based on: • Pros-to-cons ratio • Number of reviews • Category average

Sennheiser

HD 660S2

Name: HD 660S2
Brand: Sennheiser

around $499

All prices are estimates and may vary from actual prices.

242 Pros

63%
23 reviews (4h 0m)

143 Cons

Open-back audiophile headphones delivering refined sound signature for critical listening and professional use....

Summary of pros and cons from human reviewers, put together by AI

69%

150 vs 66

Sound Quality

57%

24 vs 18

Comfort

55%

28 vs 23

Value for Money

73%

19 vs 7

Build Quality

50%

10 vs 10

Design

Reviewer verdict

Across 23 YouTube reviews, the Sennheiser HD 660S2 earns a Summa score of 3.5/5, ranking #49 among Wired Earbuds. Reviewers most often praise its sound quality, value for money, comfort, while the most common criticisms concern sound quality, value for money.

The Sennheiser HD 660S2 is widely celebrated for its significant sonic improvements, particularly its enhanced bass which adds satisfying punch and sub-bass extension without sacrificing the natural, balanced character the 600 series is famous for. Reviewers consistently praise its incredible comfort, lightweight design, and durable build quality, making it suitable for hours of fatigue-free listening. The sound is described as clean, highly detailed, and musical, with a lush mid-range and crisp, non-fatiguing treble. Its versatility with various amplifiers and the inclusion of a 4.4mm balanced cable further cement its status as a top contender and a worthy evolution in a legendary headphone lineup.

The most consistent criticisms center on practical usability issues. The high 300-ohm impedance necessitates a dedicated amplifier to unlock their full potential, as performance is lacking when powered by a phone or computer. Many users report a strong initial clamping force that can be uncomfortable during long sessions, especially for those with larger heads. Furthermore, the soundstage is consistently described as intimate and narrow, which may disappoint listeners seeking a more expansive experience. Finally, the downgraded packaging and predominantly plastic build feel underwhelming for its price point compared to both predecessors and current competitors.

Analysis based on 23 YouTube reviews (4h 0m of video) with 242 pros and 143 cons extracted.

Pros (242)

Sound Quality (150)

The mids are smooth and laid back, delivering enough warmth for vocals. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 4:23
Recommended for studio use and as a neutral all-around headphone ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 14:51
Retuned driver with more bass, smoother presentation, and more musical mid-range ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 3:52
Sound is fluid, musical, super pleasing, and better than many flagships ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 4:37
Excellent treble extension, resolution, detail, and clarity ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 5:04
Incredible dynamics, resolution, and musicality with natural soundstage and good imaging ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 5:15
Effortless listening experience, never fatiguing despite brightness and detail ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 7:44
Can be driven well with good amplifiers like the S9C Pro, enhancing soundstage and holography ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 9:11
Significant improvement over the original 660s with better musicality, smoothness, and refinement ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 10:14
The bass is quite pleasing, not overly punchy but certainly noticeable. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 4:19
The Sennheiser HD 660S2 is a better iteration of the 660S, making the headphone a little more fun, engaging, and better all around. ▶ The NEW King of the Senns? 660s2 Review @ 1:00
Sound is more engaging with improved bass that goes lower and hits harder, and sparkly highs compared to the original 660S. ▶ The NEW King of the Senns? 660s2 Review @ 3:38
The headphone delivers a wonderfully reference sound without being boring, with natural vocals and timbre. ▶ The NEW King of the Senns? 660s2 Review @ 4:14
Increased impedance to 300 ohms but maintains the same sensitivity, allowing it to pair well with both tube and solid state amplifiers. ▶ The NEW King of the Senns? 660s2 Review @ 4:52
Sounds fantastic on both tube amps and solid state amps, with the reviewer liking it more on solid state in some cases. ▶ The NEW King of the Senns? 660s2 Review @ 5:24
Does not require special amplification and sounds wonderful with a variety of amps. ▶ The NEW King of the Senns? 660s2 Review @ 6:04
More neutral and accurate sound signature compared to some competitors, making it a great reference headphone. ▶ The NEW King of the Senns? 660s2 Review @ 6:40
Considered the 'king' of the Sennheiser 6 series headphones, possibly better than the 8XX or 800S models. ▶ The NEW King of the Senns? 660s2 Review @ 7:18
Great listening experience that is not boring or hard to listen to, making it a wonderful headphone overall. ▶ The NEW King of the Senns? 660s2 Review @ 7:40
Reworked tuning to provide a little more sub bass and lower end punch without being bass heavy. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 2:14
Mids are more forward with more substance, vibrance, and warmth compared to the 6XX. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 2:52
The headphones have a wide frequency response from 8 Hz to 41,500 Hz. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 3:14
Open-back design provides a wider soundscape and depth, beneficial for gaming to hear footsteps. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 3:52
Vocals are clear and the mid-range instruments shine, with excellent treble clarity and improved bass detail compared to the original 660s. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 4:40
Sub bass is kicked up, allowing hearing more nuanced notes in the bass region. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 5:24
Soundstage is fantastically wide and deep, creating a 360-degree surround sound experience. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 5:33
Designed for critical listening and audiophiles who enjoy pure sound. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 6:07
HD 660s II is undoubtedly better than the HD 660s version 1 ▶ Do Not Buy the Sennheiser HD 660S2 @ 0:41
Bass profile is not suicide tier and there are far worse bass profiles ▶ Do Not Buy the Sennheiser HD 660S2 @ 1:47
High target adherence in higher frequency regions until 3 kHz ▶ Do Not Buy the Sennheiser HD 660S2 @ 1:58
With EQ adjustments, the headphone can sound as good as possible ▶ Do Not Buy the Sennheiser HD 660S2 @ 4:24
Provides an unparalleled listening experience whether at home or on the go. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 2:33
Clean and clear sound with a flat frequency response ▶ Quick Take: Sennheiser HD 660S2 @ 2:20
Has a restrained energy with tight, explosive snap especially on percussion ▶ Quick Take: Sennheiser HD 660S2 @ 2:38
Sound is crisp and tight without being overblown or embellished ▶ Quick Take: Sennheiser HD 660S2 @ 3:36
Mayor eficiencia en la amplificación gracias a un driver con construcción diferente que maneja mejor la corriente. ▶ SENNHEISER 660S 2 REVIEW @ 3:29
Sonido cálido con graves mucho más enfatizados y contundentes, con autoridad y dinamismo. ▶ SENNHEISER 660S 2 REVIEW @ 3:50
Buena extensión en frecuencias graves y disfrutable a pesar de no ser tan natural el decaimiento. ▶ SENNHEISER 660S 2 REVIEW @ 4:30
Muy buena separación instrumental a pesar de la calidez del sonido. ▶ SENNHEISER 660S 2 REVIEW @ 6:09
Escena sonora pequeña, adecuada para monitoreo, especialmente para música electrónica. ▶ SENNHEISER 660S 2 REVIEW @ 6:29
Una buena opción para quienes buscan más graves y color en frecuencias graves y medias. ▶ SENNHEISER 660S 2 REVIEW @ 7:07
Open back headphone with 38mm dynamic driver, 300 ohms impedance, and wide frequency response (8Hz to 41.5kHz) ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 0:16
Very natural and realistic tone and timbre with good note weight in bass and mids ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 6:06
Bass extends nicely into sub bass with rumble and punch without being domineering ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 6:10
Mid bass has power and authority, with good tonality and natural sound ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 6:36
Detail retrieval and resolution is phenomenal, revealing all intricacies without being force-fed ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 6:57
Mids have naturalism, good space and air, and accurate vocal and instrument reproduction ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 7:38
Treble is extended with sparkle, energy, crispness and slight bite without causing fatigue ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 8:48
Balanced and cohesive sound signature across bass, mids, and treble ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 9:52
Soundstage is wide enough but intimate, with good depth and excellent layering and imaging ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 10:03
Imaging is precise and accurate, allowing detailed track dissection ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 11:14
Tone and timbre are exceptional and natural, with broad instrument range and no roll-off ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 12:08
Outperforms original 660 with better bass extension, note weight, detail, and resolution ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 12:56
Better detailed and resolving than HD 600, with more balanced and cohesive sound ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 14:41
Accurate and neutral bass response that reflects what the producer intended, with a more energized and pronounced bass compared to predecessors. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 5:39
Balanced and natural mid-range where vocals and instruments coexist in harmony without overshadowing each other. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 7:24
Full-bodied and expanded treble with more micro details and a delicate balance between clarity and avoiding harshness or fatigue. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 8:28
Precise imaging with instruments placed where they should be, providing a realistic soundstage consistent with the series. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 9:54
Balanced and versatile sound signature, making it a good all-around headphone and potentially the last headphone one might need. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 11:32
Retains the lovely mid-range that makes the 600 series so good, with subtle enhancements and faithful sound production. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 13:33
The HD6 series has an incredibly well-earned reputation for being neutral and natural sounding. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 2:00
The HD6 series has a well-balanced bass, mids, and treble across the board. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 10:31
The HD6 series is a versatile and natural sounding headphone that makes few trade-offs. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 11:01
Has a darker and warmer sound compared to the rest of the 6xo line, which some listeners may prefer ▶ HD660S2 - The side-grade we've been waiting for? @ 3:25
Bass is decent and technically more than the original 660s version one ▶ HD660S2 - The side-grade we've been waiting for? @ 2:25
Recessed 3 kHz treble gives an illusion of a wider soundstage and more spacious separation on some music ▶ HD660S2 - The side-grade we've been waiting for? @ 2:44
Good headphone for people who want less treble in the 3 kHz range and less shoutiness ▶ HD660S2 - The side-grade we've been waiting for? @ 4:19
Sounds thick, rich, and wide especially on tube amps with certain music genres like old Linkin Park albums ▶ HD660S2 - The side-grade we've been waiting for? @ 5:18
Timbre and tonality are consistent and legendary for Sennheiser ▶ HD660S2 - The side-grade we've been waiting for? @ 9:35
The Sennheiser HE1 headphones are an extraordinary piece of tech with ultimate unadulterated uninterrupted most proper listening experience. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 3:24
The sound is warm, smooth, with incredible separation between instruments, wide and immersive soundstage, crisp, airy, and clean without harshness. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 5:50
The HE1 headphones provide a hyper-real and euphoric listening experience with great appreciation for subtle details and dynamics in music. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 6:40
The HE1 manages to have articulation, space, weight, and clarity without being honky, tubby, bloated, sharp, or plasticky like many other headphones. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 7:51
High-fidelity open back headphone delivering natural relaxed sound with added punch in the subbase range. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 0:25
Built with ultra light aluminum voice coils and 300 ohm impedance for impressive impulse response and detailed listening experience. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 0:35
Airflow optimized 42mm high-performance transducers minimize distortion and ensure controlled air displacement. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 0:48
Clear, crisp, and immersive sound across deep bass to sparkling highs with frequency response from 8 Hz to 41,500 Hz. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 1:04
Impressive subbase performance allowing you to feel low-end frequencies with precision and clarity. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 1:26
Excellent balance and deep immersion for bass-heavy tracks and orchestral music. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 1:53
Stands out for subbase performance compared to other high-end models. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 3:38
Offers incredible sound stage and immersive listening experience hard to match. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 5:21
Sound presentation is effortless and relaxing even at higher volumes. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 2:25
Bass is more enjoyable and engaging compared to HD 650, with impactful mid-bass slam. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 2:57
Mid-range shines best with clear, full vocals placed in front of instruments, providing an intimate and lush session. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 3:30
Treble is tamed compared to HD 650, avoiding harshness while maintaining enough bite and air for instruments and vocals. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 4:05
Soundstage and imaging are good with decent separation and positioning of sounds. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 4:59
Tuning is deliberate and careful, balancing bass, treble, and clarity without harshness. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 5:44
Can be EQ'd for more bass or treble but at the cost of losing headphone's identity. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 5:44
300 ohm impedance allows good power handling with minimal gains beyond certain volume. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 6:06
Overall sound is balanced, providing everything needed without emphasizing any frequency too much, making it easy to listen to for long periods. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 6:24
Treble response is good, not sibilant or harsh, maintaining a clean and clinical sound signature. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 2:59
Detail, clarity, and transparency are strong, consistent with HD600 series quality ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 4:03
Improved bass extension and presence compared to previous HD600 series headphones ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 4:15
Great texture and detail in the low end instruments ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 4:49
Full, rich mid-range with great weight, layering, and natural presentation of acoustic instruments and vocals ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 5:02
Well-balanced treble with good presence, extension, and air, providing a revealing upper end ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 5:29
Moderate to narrow soundstage width but with good depth, height, and front-to-back imaging for a three-dimensional feel ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 5:47
Improved bass extension and quantity elevates the 660 S2 above the original HD 660s, providing more accurate bass that enhances overall sound naturalness ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 8:55
Better balance across the frequency range with added richness to mids and balanced treble ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 9:30
Sound is more accurate, engaging, intense, and revealing compared to more relaxed alternatives ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 11:45
Incremental updates create a real evolution of the product, possibly making it the best HD 600 series headphone yet ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 12:43
Sennheiser managed to tune the HD 660 S2 differently to address bass feedback from the previous model. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 0:12
Improved bass response compared to the previous 660s model. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 4:19
Well-balanced mids and fine-tuned sound suitable for jazz, rock, classical, and electronic music bass. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 4:31
Very good dynamic range and imaging, allowing clear instrument and vocal placement. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 5:53
Sound grows on the listener over time, appealing to those who prefer warmer sound signatures. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 6:18
Great for people who like warm sound, smooth highs, and more bass than the 660s. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 7:18
Good for watching movies due to spacious and immersive soundstage. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 7:01
Bass is similar to the HD 600, with a classic HD 580/600 style bass response. ▶ Sennheiser HD 660S Review - The New, New Reference @ 4:32
Mid-range fixes the shouty mid-range of the HD 600 while maintaining excellent timbre, resulting in fantastic mids. ▶ Sennheiser HD 660S Review - The New, New Reference @ 6:04
Mids are slightly faster and more resolving than the HD 600 and 650. ▶ Sennheiser HD 660S Review - The New, New Reference @ 7:06
Treble is the brightest in this Sennheiser line, providing wonderful micro detail without being strident at normal listening levels. ▶ Sennheiser HD 660S Review - The New, New Reference @ 7:28
Soundstage is similar to the HD 600, with classic imaging characteristics. ▶ Sennheiser HD 660S Review - The New, New Reference @ 8:20
Very neutral sound signature, suitable for almost any genre. ▶ Sennheiser HD 660S Review - The New, New Reference @ 9:31
Overall an upgrade to the HD 600, especially in mid-range clarity and detail retrieval. ▶ Sennheiser HD 660S Review - The New, New Reference @ 11:38
Pads significantly affect sound quality; brand new pads provide more bass, mids, and treble, enhancing the listening experience. ▶ Sennheiser HD 660S Review - The New, New Reference @ 13:48
The HD 660S2 delivers a stage sound and detail retrieval that genuinely has no equal at their price points. ▶ Best & Worst Sennheiser Headphones From Every Generation (Au @ 11:49
The Sennheiser house sound offers honest, uncolored mid-range that tells the truth about your mix. ▶ Best & Worst Sennheiser Headphones From Every Generation (Au @ 12:05
Latest and greatest from the 600 line of headphones ▶ The NEW HD660S2! - $600!? @ 0:25
Slightly elevated treble response makes the top end of guitars and string instruments seem relatively complete compared to previous models ▶ The NEW HD660S2! - $600!? @ 3:08
Provides a little bit more texture and evidence that those sounds were there ▶ The NEW HD660S2! - $600!? @ 3:26
Sounds very clean and clear, not sharp or overbearing ▶ The NEW HD660S2! - $600!? @ 4:08
Mid-range is more detailed but less frequency forward, providing a clearer and less syrupy sound ▶ The NEW HD660S2! - $600!? @ 5:16
Allows background instruments to be more present in listening ▶ The NEW HD660S2! - $600!? @ 6:24
Probably the clearest sounding bass with the most fidelity compared to previous generations ▶ The NEW HD660S2! - $600!? @ 7:13
More precise sub bass than other versions ▶ The NEW HD660S2! - $600!? @ 7:26
Still a relatively focused headphone with familiar 600 series sound but with slight tweaks ▶ The NEW HD660S2! - $600!? @ 10:30
Better sub bass presence compared to HD 650 or HD 600, providing better bass depth ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 2:25
Creamy, warm, enticing mid-range typical of Sennheiser headphones, with lush, lifelike, warm analog sound ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 3:32
Mid-range is slightly more restrained and less shouty than HD 650, resulting in less congestion on busy tracks ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 4:23
Wider soundstage and better perceptional resolution due to recessed upper mids and treble ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 5:48
Improved imaging and sound staging compared to previous 6xo lineup ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 9:14
Masterclass timbre, very natural and pleasing tonal quality ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 9:52
Redesigned voice coil and driver assembly with improved bass and higher transparency ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 0:19
Slightly shorter voice coil transferring more power to drivers ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 2:14
Optimized airflow reducing unwanted sound waves and vibration, resulting in lower distortion and clearer sound ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 2:45
Resonant frequency dropped from 110 to 70 Hz, increasing bass output by 5-6 dB in lowest octaves ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 3:01
Thicker, warmer, more organic and natural sound compared to HD 650 but with more information in sub-bass and upper treble ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 4:27
Improved bass with more punch, definition, and clarity especially in sub-bass region ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 4:39
Better transient response with faster decay and better timing ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 5:15
Better resolving abilities and more detailed retrieval compared to predecessors ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 5:26
More complete sounding headphone with extended bass frequency response ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 5:34
Mid-range is velvety smooth, organic, clear, and technical sounding ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 13:03
More detailed and extended treble without causing listening fatigue ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 13:40
Drivers are exceptionally matched offering exemplary bass and mid-range performance ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 14:20
Less vibration and ringing in cups, resulting in clearer imaging and better transparency ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 14:43
Slightly warmer, thicker, more natural and technical sounding than previous models ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 15:19
Features a closedback design with advanced transducers delivering rich, detailed sound across a wide frequency range from deep bass to crystal clear highs. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 0:59
Incredibly detailed driver structure creating an immersive sound experience. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 1:31
Uses a combination of acoustic and mechanical features to achieve superior sound quality without compromising comfort or style. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 2:24

Value for Money (28)

Priced affordably around $399, making it mid-range despite being a flagship headphone ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 1:10
Comes with a dust-covering pouch for protection during transport ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 3:13
The packaging includes two sets of generic cables with different connectors and an adapter for 3.5mm jack, plus a storage pouch for travel or dust protection. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 1:04
Competes well with other high-end headphones in the $500-$600 price range, holding its own against models like the Ananda and Meze 109. ▶ The NEW King of the Senns? 660s2 Review @ 6:14
Highly recommended as a durable, long-lasting, and versatile reference headphone. ▶ The NEW King of the Senns? 660s2 Review @ 6:58
The carrying pouch is a soft pouch, easier for portability compared to the original hard shell case. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 0:45
The cables are detachable and come with multiple options including 6.3mm, 4.4 balanced cable, and 6.3mm to 3.5mm adapter. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 1:56
Incredible value for money and incredibly durable and long-lasting with proper care. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 2:59
Commitment to quality and customer satisfaction sets it apart from others. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 3:31
Incredible sound, quality, comfort, and style make it highly recommended by audio files and music lovers. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 3:43
Advanced noise isolation technology, detailed driver structure, and sleek design make it a worthwhile investment. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 4:04
The HD6 series is inexpensive compared to many other headphones that sound worse or are less comfortable. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 11:58
The HD6 series is still competitive and a great value today. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 12:15
Sennheiser is a trusted and loved family-owned German audio company known for some of the best microphones and headphones. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 0:50
Designed for those who demand an elevated listening experience. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 0:16
Premium option geared towards serious audio files valuing accuracy and deep bass. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 3:08
Brand has a solid reputation for good customer service. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 4:41
Includes a variety of cables including a lightweight balanced cable and 6.35mm jack cable, plus a carrying pouch. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 3:03
Price point of 600 Euro is reasonable for the quality offered. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 8:02
Comes with an upgraded HD 650 style cable and a new pentacon Sony balanced cable for modern balanced amps. ▶ Sennheiser HD 660S Review - The New, New Reference @ 1:33
Sennheiser has a legendary reputation for serious home listening and reference accurate monitoring. ▶ Best & Worst Sennheiser Headphones From Every Generation (Au @ 11:41
Comes with an additional 4.4 millimeter balanced cable ▶ The NEW HD660S2! - $600!? @ 2:33
Good complement to HD 650 and HD 600, recommended for collectors or fans of the 6xo lineup ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 11:07
Overall rating of A minus due to tonality, comfort, ergonomics, and durability ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 10:35
Works well with a wide range of headphone amplifiers including portable, desktop, tube, and solid state ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 3:30
Price is reasonable considering decades of refinement ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 15:49
Sennheiser HD 660S2 is an investment that will last you years to come. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 0:12
Praised by countless reviewers and audiophiles for exceptional sound quality and comfort. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 1:54

Comfort (24)

Immense comfort with redesigned feel better than the original 660s ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 0:50
Lightweight and have spongy cushioning on the headband for comfort ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 2:39
The headphones are super lightweight, so they don't feel like a big load on your head. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 2:18
The headphones feel very comfy and very light, feeling like wearing air. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 1:08
The padding is very comfortable and soft, making listening sessions weightless and enjoyable. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 2:34
Light and comfortable clamp ▶ Quick Take: Sennheiser HD 660S2 @ 1:50
Extremely comfortable to wear for 5-6 hours, lightweight at 260 grams, pads and clamp force soften over time ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 3:52
Comfortable and soft ear pads with good support, suitable for long periods of use despite high clamping force. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 4:14
The HD6 series is a solid chassis for comfort overall, especially for smaller heads. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 8:54
The HD6 series has a good range of adjustment and can fit larger heads well. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 1:26
Comfortable after break-in despite initial clamp pressure ▶ HD660S2 - The side-grade we've been waiting for? @ 1:37
Comfortable open back design with plush ear cushions that prevent heat buildup and discomfort during long listening sessions. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 2:08
The headphone is very comfortable to wear for hours due to plush ear cuffs, soft headband cushion, and lightweight design. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 1:59
Velour ear pads are comfortable and conform to the head and ears over time. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:03
Lightweight plastic construction makes the headphones comfortable and not fatiguing to wear for long sessions. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:26
Open-back design with comfortable velour pads that don't get hot, suitable for long listening sessions. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:32
Comfortable enough to wear for extended periods, including 8-hour work sessions. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:38
Velour ear pads are comfortable for long periods, sweat resistant, and durable compared to pleather pads ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 3:32
Lightweight at 260 grams, allowing for longer music sessions without fatigue. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 1:27
Plush and comfortable earpads that provide great cushioning and keep ears away from the driver. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 2:08
Comfortable headband with two-piece cushioning, providing good comfort on top of the head. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 2:41
Comfort improves after break-in despite initially high clamping force. ▶ Sennheiser HD 660S Review - The New, New Reference @ 2:41
Good headphone with a very ergonomic design, super light and comfortable to wear around the house or even in bed ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 1:42
Despite being closedback, they don't make you feel claustrophobic or cut off from surroundings. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 1:13

Build Quality (19)

Balanced cable has low microphonics and good build quality ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 8:19
The build feels solid and well put together despite being lightweight and somewhat plasticky. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 3:34
Build quality is consistent with other Sennheiser 6 series headphones, known for durability and comfort. ▶ The NEW King of the Senns? 660s2 Review @ 1:21
Built to last with well-engineered plastics and materials ▶ Quick Take: Sennheiser HD 660S2 @ 1:56
La construcción es bastante sólida, duradera y ligera, destacando la comodidad de la serie 600. ▶ SENNHEISER 660S 2 REVIEW @ 1:33
Build quality similar to original 660 with copper lettering and logos, comfortable velour pads and cushy headband ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 2:09
The HD6 series has excellent industrial design, comfort, weight, durability, and user serviceability. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 11:45
Build and design are familiar and well time-tested with interchangeable parts ▶ HD660S2 - The side-grade we've been waiting for? @ 0:39
The HE1 headphones are beautifully constructed out of metal, open-backed, and incredibly comfortable. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 4:59
Stellar build quality with durable structure and design prioritizing comfort, made in Ireland and designed in Germany. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 4:11
Build quality is consistent with previous models and has proven durability over decades. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 3:19
Follows Sennheiser standard HD600 series design with solid build quality mixing plastic and metal ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 1:17
High build quality with sturdy plastic and metal grids, engineered in Germany and produced in Ireland. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 1:03
Build quality is about the same as the HD 600 and 650, with a matte black color scheme. ▶ Sennheiser HD 660S Review - The New, New Reference @ 0:28
Pads may use tougher foam that could last longer and maintain sound quality better. ▶ Sennheiser HD 660S Review - The New, New Reference @ 1:10
Same exact build quality that we have come to know and love on the hc600 series ▶ The NEW HD660S2! - $600!? @ 1:20
Durable build quality typical of Sennheiser headphones, lasting well with heavy usage ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 8:45
Build quality similar to predecessors with minor improvements like flat cup holders and bronze accents ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 1:33
Compatible with previous cables and ear pads ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 15:35

Design (10)

Fully open-back design offering true open-back sound experience ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 3:38
The open back ear cups have a striking aesthetic with copper branding that adds a dash of luxury. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 2:52
The metal mesh provides more airflow. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 1:18
Classic and timeless design that will never get old, with durable plastics and metal grills. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 3:19
Offers incremental innovations without redefining the series, maintaining the lineage while providing modern and unique features. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 12:00
Maintains traits loved from the rest of the line with some new aesthetic changes like flat edges and bronze accents ▶ HD660S2 - The side-grade we've been waiting for? @ 0:28
The marble used in the HE1 is extracted from the same marble used for the Statue of David, adding to its uniqueness. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 3:27
The HE1 headphones have fins for cooling because part of the amplifier is built into the headphone, and they are electrostatic with no magnets. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 5:03
Straightforward setup with design focused on desktop use and long detachable cables. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 2:01
Designed with comfort and style in mind, featuring a sleek, ergonomic design that fits perfectly without putting too much pressure. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 1:20

Connectivity (7)

Includes balanced and single-ended cables, with a balanced 4.4mm jack cable included ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 2:59
Comes with multiple cables including a 5-foot and an 8-9 foot quarter inch cable, plus a quarter inch to 3.5mm adapter. ▶ The NEW King of the Senns? 660s2 Review @ 1:50
Comes with a 4.4 millimeter balanced cable, which the previous 6XX did not include. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 1:46
Incluye un cable 4.4mm, lo cual es de agradecer por la entrada especial de Sennheiser. ▶ SENNHEISER 660S 2 REVIEW @ 2:51
Comes with two cables (quarter inch and 4.4 balanced) with 1.8 meter length, better than previous 3 meter cables ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 1:19
Updated cables include both 4.4mm and 6.3mm connectors with a more manageable 6-foot length ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 2:29
Smaller packaging with soft carry pouch and shorter cables with balanced 4.4mm jack ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 1:08

Durability (3)

Likely to have staying power and be kept for many years like other 6xo series headphones ▶ HD660S2 - The side-grade we've been waiting for? @ 9:08
Promising longevity over time. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 4:24
Designed in Germany and manufactured in Ireland ensuring long service life ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 1:54

Noise Isolation (1)

Advanced noise isolation technology effectively blocks out background noise while allowing focus on music. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 2:13

Cons (143)

Sound Quality (66)

High impedance of 300 ohms makes them hard to drive without a quality amplifier ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 8:27
Bass is not very strong or sub-bass heavy, which may not satisfy bass lovers. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 2:41
Trumpet and some instruments lack note clarity and sharpness due to tuning. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 4:35
Sound is not the most detailed or resolving compared to HD 650, sounding a bit more blended. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 5:00
Not a huge leap or night and day difference from the original 660S, just incremental improvements. ▶ The NEW King of the Senns? 660s2 Review @ 1:00
Deficient in sub bass and significantly overshoots in the lower mid-range causing lack of punch and too much bloat ▶ Do Not Buy the Sennheiser HD 660S2 @ 1:39
Massive suck out in the response at 3 kHz, present in original HD 660s and not addressed in this version ▶ Do Not Buy the Sennheiser HD 660S2 @ 2:01
Bass profile is basically the same as the HD 650 which was released decades ago ▶ Do Not Buy the Sennheiser HD 660S2 @ 2:22
Can be shrill at times with a hazy, crowded symbol wash in the upper mids ▶ Quick Take: Sennheiser HD 660S2 @ 3:48
Upper mids and treble region can be irritating and too energetic for sensitive listeners ▶ Quick Take: Sennheiser HD 660S2 @ 4:07
Requires the right amp pairing to balance sound, preferably a warm tube amp or thick solid state amp ▶ Quick Take: Sennheiser HD 660S2 @ 4:20
Sound is too flat and analytical, lacking romance and emotional engagement ▶ Quick Take: Sennheiser HD 660S2 @ 5:09
Does not inspire toe tapping or emotional connection, more like observing than enjoying music ▶ Quick Take: Sennheiser HD 660S2 @ 6:00
Sonido más oscuro que la versión anterior, con medios que se obscurecen bastante debido a los graves. ▶ SENNHEISER 660S 2 REVIEW @ 4:01
Los medios no son tan naturales, especialmente en voces femeninas que pierden naturalidad y detalle. ▶ SENNHEISER 660S 2 REVIEW @ 5:01
Los agudos son demasiado suaves, lo que puede hacer que falte detalle en esa zona. ▶ SENNHEISER 660S 2 REVIEW @ 5:45
La escena sonora es muy pequeña, lo que puede no ser ideal para quienes buscan un sonido más espacioso. ▶ SENNHEISER 660S 2 REVIEW @ 6:29
No es recomendable para quienes buscan un sonido cristalino y con mucho detalle. ▶ SENNHEISER 660S 2 REVIEW @ 7:26
No se siente tan natural como la versión anterior 660s, especialmente en los medios. ▶ SENNHEISER 660S 2 REVIEW @ 7:54
The sound profile is balanced but uneventful, lacking any standout qualities. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 3:54
The soundstage is decent but not immersive or dynamic. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 4:12
The treble is quite reserved, which might reduce detail. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 4:30
Not easy to drive; sounds inadequate from dongles or straight from computer ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 4:29
DAPs improve sound but balanced desktop setups are preferred for best performance ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 4:49
Soundstage is intimate and does not have a grand or wow factor for size ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 10:34
Sometimes treble can have a little zinginess but not overly fatiguing ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 8:56
Sub-bass lacks deep rumbling lows, which may disappoint those craving more bass impact. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 5:39
Dynamics and punch are average and do not stand out. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 10:50
Soundstage remains intimate and somewhat narrow, consistent with the series but not expansive. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 9:48
Some listeners might find the treble slightly fatiguing compared to previous models due to lack of warmth. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 9:40
The HD6 series can be boring or not exciting for some listeners due to its neutral tuning. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 0:49
The HD6 series lacks bass, especially sub-bass, which rolls off early. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 2:17
The HD6 series has no sound stage or out-of-head distance effect, making it sound very headphone-like. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 1:40
Loses intimacy in the vocal region compared to previous models like the 6xx and 650 ▶ HD660S2 - The side-grade we've been waiting for? @ 2:10
Recessed treble around 3 kHz can make some music sound less forward and intimate ▶ HD660S2 - The side-grade we've been waiting for? @ 2:44
Not an improvement in technical detail over HD 650, 660s, or 600 ▶ HD660S2 - The side-grade we've been waiting for? @ 3:44
Dark and warm sound can be overwhelming on some tracks, e.g. Nirvana's 'Something in the Way' ▶ HD660S2 - The side-grade we've been waiting for? @ 4:59
More bass than 660s version one but less bass and sub-bass than 6xx on measurements ▶ HD660S2 - The side-grade we've been waiting for? @ 2:30
Soundstage width is somewhat narrow compared to some competitors ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 5:47
Treble can be a little bright and revealing, which might not suit listeners preferring a more relaxed sound ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 5:29
Some users may still find the bass lacking depending on personal taste. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 0:25
High frequencies are less bright and crisp than some may prefer, making them less ideal for those wanting very bright sound. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 4:36
Not the best headphones in terms of imaging compared to other high-end models. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 7:10
Worse upper mid-range performance with a big suck out at 4 kHz killing detail ▶ Do Not Buy the Sennheiser HD 660S2 @ 2:33
Huge scoop from 3 kHz to 6 kHz killing detail ▶ Do Not Buy the Sennheiser HD 660S2 @ 2:40
Excess in lower mid-range causing mud in the headphone, not acceptable ▶ Do Not Buy the Sennheiser HD 660S2 @ 3:23
Upper treble sounds bright due to huge suck out in upper mid-range ▶ Do Not Buy the Sennheiser HD 660S2 @ 3:49
Bass has a roll-off starting around 100 Hz and lacks sub-bass extension, which may not satisfy sub-bass focused listeners. ▶ Sennheiser HD 660S Review - The New, New Reference @ 5:11
Treble can be slightly peaky above 10 kHz and may be a bit bright for electronic music fans. ▶ Sennheiser HD 660S Review - The New, New Reference @ 8:07
Soundstage is not very wide and does not fill the space between center and edges well. ▶ Sennheiser HD 660S Review - The New, New Reference @ 8:20
If you want earth-shaking bass for electronic music or hip-hop, Sennheiser's neutral tuning will feel cold and unsatisfying. ▶ Best & Worst Sennheiser Headphones From Every Generation (Au @ 12:28
Not significantly more detailed than previous headphones in the series ▶ The NEW HD660S2! - $600!? @ 3:44
Treble response can be a detriment compared to competitors at this price that seem more detailed ▶ The NEW HD660S2! - $600!? @ 3:57
Mid-range reduces focus compared to previous generations, which some may dislike ▶ The NEW HD660S2! - $600!? @ 6:10
Does not have a notably bassier sound than previous generations, and bass is not as strong as competitors like Focal LX or 109 Pro ▶ The NEW HD660S2! - $600!? @ 6:36
Bass improvements are subtle and not a significant bump in clarity or detail ▶ The NEW HD660S2! - $600!? @ 7:38
Slight dip around 3000 Hz and elevated treble above 10,000 Hz may affect listening experience ▶ The NEW HD660S2! - $600!? @ 9:10
Not a big jump in quality compared to other 600 series headphones ▶ The NEW HD660S2! - $600!? @ 10:06
Not a basshead headphone, bass does not slam hard ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 3:23
Resolution is not a significant step up from HD 650 or HD 600, not very resolving ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 7:03
Not very fast or snappy, does not work well with fast music, metal, or rock due to lack of slam ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 9:27
Dynamics are a bit compromised as with other Sennheiser 6xo headphones ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 9:42
Slightly lower sensitivity (104 dB) due to 300 ohm impedance making them less efficient ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 2:34
Not as fast sounding as some other headphones, speed is improved but still moderate ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 8:59
Bass slam and soundstage not as impressive as high-end planar magnetic headphones ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 9:14
Soundstage is mid-forward and not very wide, not suitable for out-of-head experience ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 9:29

Value for Money (23)

No transport carrying case included, only a pouch ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 1:55
Need to spend additional $200-$300 on a good amplifier to drive them properly ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 8:42
Price is somewhat high at $500-$600, which may be a hesitation point for some buyers. ▶ The NEW King of the Senns? 660s2 Review @ 6:11
HD 660s II is still a joke especially for the asking price ▶ Do Not Buy the Sennheiser HD 660S2 @ 0:44
Cherry-picked reviewers were used to hype up the product before release ▶ Do Not Buy the Sennheiser HD 660S2 @ 0:53
The packaging lacks a hard shell case which would have been a nice touch. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 1:01
Overall, the headphones lack distinct advantages and may be outperformed by other models in the same price range. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 5:11
Packaging is uninspiring and lacks a big hard shell carrying case like the original 660 ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 0:57
No 4.4 balanced adapter included ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 1:52
Not much point in buying if you already own a highly detailed headphone like the Focal Clear, as it doesn't offer a drastically different sound. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 11:23
May not be the best choice for headphone collectors who already own many headphones, as other headphones can do what this does with more uniqueness. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 13:04
At this price range, there are headphones with more technical detail though they may lack staying power ▶ HD660S2 - The side-grade we've been waiting for? @ 8:46
Price is significantly higher ($499 on sale vs $199 for 6XX) without corresponding improvements in packaging or extras. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 0:35
Predicted preference rating of 69.63 is not very good, likely to score low in double-blind tests ▶ Do Not Buy the Sennheiser HD 660S2 @ 2:56
EQ is needed to fix major issues but not really worth it for a $600 headphone ▶ Do Not Buy the Sennheiser HD 660S2 @ 3:56
Overall not worth the price and not recommended to buy ▶ Do Not Buy the Sennheiser HD 660S2 @ 5:10
Price is high at MSRP $499; recommended to buy under $399 for better value. ▶ Sennheiser HD 660S Review - The New, New Reference @ 16:17
Most expensive in the 600 series at a whopping $600, which is insane for the series ▶ The NEW HD660S2! - $600!? @ 0:41
Competition above $500 is very steep, making it hard to compete ▶ The NEW HD660S2! - $600!? @ 10:19
Does not live up to the very high bar set by HD 650 and HD 600 ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 0:38
Minimal accessories included, just basic cables and a small pouch ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 0:59
If starting out with $600 budget, HD 6xx is still recommended over HD 660 S2 ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 11:18
Some cheaper alternatives have wider soundstage and more impressive soundstage capabilities ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 10:09

Comfort (18)

Can feel tight on the head and headband made of plastic that doesn't stretch much ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 2:32
Ear cups can get a little hot especially during summer. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 2:19
Some users have reported issues with the ear cushions, finding them uncomfortable after extended wear. ▶ Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... @ 3:20
Puede generar cierta presión en cabezas más pequeñas, aunque con el tiempo se afloja el plástico. ▶ SENNHEISER 660S 2 REVIEW @ 2:04
The clamping force is more significant than anticipated, which could be uncomfortable for long listening sessions. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 1:44
The velour-like ear pads combined with clamping force can create a heat trap during longer usage. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 1:57
Has some clamp force initially that requires break-in period to loosen up ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 2:53
High clamping force may cause discomfort for people with larger heads over long listening sessions. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 4:40
The HD6 series has issues with top of head comfort and clamp force, especially for large heads. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 1:14
Clamp pressure is very strong out of the box and might be too much for some people ▶ HD660S2 - The side-grade we've been waiting for? @ 1:39
Can feel cumbersome due to weight and size compared to similarly priced models. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 3:56
Clamp pressure feels a bit tight initially, though it loosens over time. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:11
Clamp force is strong and can feel clampy or uncomfortable initially, especially for larger heads ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 2:03
Compared to the Ibasso SR3, the 660 S2 is less comfortable due to stronger clamp force ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 8:20
Headphones are a bit tight and can squeeze the head, potentially causing fatigue during long sessions. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 1:50
Earpad filling is not memory foam, though cushioning is still good. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 2:24
Pads are firm out of the box and may cause discomfort initially due to high clamping force. ▶ Sennheiser HD 660S Review - The New, New Reference @ 2:41
Clamp is very clampy initially, though becomes comfortable after wearing ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 1:39

Design (10)

The packaging and accessories are simpler and less fancy compared to previous 6 series models, with only a small pouch included. ▶ The NEW King of the Senns? 660s2 Review @ 3:03
Adjustment of the headphones could be a little easier. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 2:53
The headphones are large, which might not suit everyone. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 4:07
El diseño no presenta cambios significativos respecto a versiones anteriores, solo cambios en color del logo y letras. ▶ SENNHEISER 660S 2 REVIEW @ 2:33
The left and right labels are inconspicuously placed and hard to see, making cable matching more challenging. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 2:26
Build quality is solid but headphones are bulky and not very portable. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 2:59
Packaging is minimal with just a cardboard box and no premium case, which feels underwhelming. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 0:51
Design is largely unchanged from previous 600 series models and doesn't stand out much. ▶ Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open B @ 1:15
Packaging is a major downgrade from previous models, coming in a cheap cardboard box with no foam, not suitable for storage or display. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 1:18
Box packaging is a downgrade from previous foam storage cases, feels like a cost reduction despite higher price ▶ The NEW HD660S2! - $600!? @ 1:43

Connectivity (7)

Uses proprietary two-pin connector for cables, limiting cable options ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 8:03
The cables are shorter (1.8 meters) compared to the original 660s which had a 3 meter cable. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 2:16
300 ohm impedance means they require an amplifier for full potential; not ideal for direct connection to phones or low powered devices. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 2:47
Not an easy-to-drive headphone due to 300 ohm impedance, requiring a good quality amplifier for best performance. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 4:46
Cable length reduced from about 10 feet to 6 feet, which may not suit everyone ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 2:33
Require an amplifier due to 300 ohm impedance; not suitable for direct connection to phones without amplification. ▶ Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser @ 5:37
Still hard to drive and requires a proper headphone amplifier; not ideal for mobile or phone use. ▶ Sennheiser HD 660S Review - The New, New Reference @ 11:14

Build Quality (7)

The build feels a bit plasticky, which might not appeal to those expecting a high-end luxury feel. ▶ Sennheiser HD 660S2 Headphones Review. Are They Worth the Pr @ 3:19
Cable is utilitarian and not very impressive; many replacement cables are available. ▶ Sennheiser HD660S2 Review! Evolution or Stagnation? An Audio @ 5:02
Plastic construction, while durable, is less premium compared to other headphones in this price range that use metal or wood. ▶ Unboxing the $600 Sennheiser HD 660S2 - The Results Will Sho @ 3:28
Pads tend to go flat quickly, which changes the sound significantly and requires replacement pads that are expensive. ▶ Sennheiser HD 660S Review - The New, New Reference @ 3:34
Build is still made of complete plastic, which can be a complaint ▶ The NEW HD660S2! - $600!? @ 1:38
Plastic build feels less premium compared to some competitors ▶ Sennheiser HD660S2 Impressions: Solid Headphone But… @ 8:36
Build quality changes are a minus for those expecting a complete redesign ▶ World Premiere Sennheiser HD 660S2 Review - The Saga Continu @ 15:35

Noise Isolation (6)

There is a lot of sound leakage due to the open-back design, making them unsuitable for quiet environments like libraries. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 3:23
Isolation of outside noise is poor due to open back design ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 4:20
Open back design causes sound leakage, not ideal for noisy environments or private listening. ▶ Sennheiser HD 660S2 Review: Is This Audiophile Headphone Wor @ 2:38
Super open design leaks sound, making them unsuitable for use outside quiet private spaces ▶ Sennheiser HD 660S2 Review | Reference Sound Evolved @ 1:39
No isolation due to open-back design, making it unsuitable for use in noisy environments or public transport. ▶ Sennheiser HD 660S Review - The New, New Reference @ 8:52
Sennheiser's passive isolation is genuinely underwhelming compared to Sony or Bose, making it less ideal for commuters or gym goers. ▶ Best & Worst Sennheiser Headphones From Every Generation (Au @ 12:16

Durability (5)

Not designed for outdoor use due to open-back design and dust/water vulnerability ▶ Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The T @ 2:10
Pads will need replacement over time; alternate pads change the sound negatively ▶ Sennheiser HD660S2 - The New Reference Standard Under 1k? - @ 3:15
The pads wear out and affect the sound signature, requiring frequent replacement which can be expensive. ▶ Why You SHOULDN'T Buy HD 600... & What To Get Instead @ 2:30
Pads need to be replaced often, which is common with Sennheiser headphones ▶ HD660S2 - The side-grade we've been waiting for? @ 6:27
One unit of the Sennheiser HE1 was found broken with marble cracked and chunks missing, raising concerns about durability and shipping safety. ▶ AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the Fir @ 2:03

Microphone Quality (1)

No built-in microphone, requiring an external mic setup for gaming or calls. ▶ Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNP @ 4:03

Review sources

Sennheiser HD660S2 - The New Reference Standard Under 1k? - The Honest Audiophile by the Honest Audiophile — 17 pros, 9 cons
World Premiere Sennheiser HD 660S2 Review - The Saga Continues by Soundnews — 20 pros, 6 cons
The NEW HD660S2! - $600!? by Joshua Valour — 11 pros, 11 cons
Sennheiser HD 660S2 Dynamic Headphones - Refinement Of The Traditional Series by Audiophile Heaven — 14 pros, 6 cons
Sennheiser HD 660S Review - The New, New Reference by metal571 — 12 pros, 8 cons
Sennheiser HD 660S2 Review: Is This Audiophile Headphone Worth the Investment? by Reviewsinside — 15 pros, 4 cons
Sennheiser HD 660S2 Review | Reference Sound Evolved by Bloom Audio — 13 pros, 6 cons
Sennheiser HD660S2 REVIEW - The Legend Reborn @sennheiser by Tech Space — 13 pros, 6 cons
Sennheiser HD660S2 Impressions: Solid Headphone But… by Amplify Audio Reviews — 10 pros, 9 cons
HD660S2 - The side-grade we've been waiting for? by DMS — 10 pros, 8 cons
Sennheiser HD660S2 Review! Evolution or Stagnation? An Audiophile's Verdict by The Sound Analyst — 9 pros, 8 cons
Is 2 Better Than 1? Sennheiser HD660S2 Dynamic Driver Open Back Headphone | My Honest Experience by RNARexperience — 10 pros, 6 cons
The NEW King of the Senns? 660s2 Review by MrAyrit — 13 pros, 3 cons
Is the NEW 660S2 an IMPROVEMENT? - Sennheiser HD 660S2 | UNPACK IT! by Canada Computers & Electronics — 11 pros, 5 cons
Do Not Buy the Sennheiser HD 660S2 by Sharur — 4 pros, 12 cons
SENNHEISER 660S 2 REVIEW by Richard Box Reviews — 8 pros, 8 cons
Sennheiser HD 660S2 Headphones Review. Are They Worth the Price? by SoundStage! Network — 6 pros, 9 cons
Unboxing the $600 Sennheiser HD 660S2 - The Results Will Shock You! by Very Important Geeks — 9 pros, 5 cons
Sennheiser HD 660S2 Review 2026 - Don't Waste your Money... by Verified Reviews — 13 pros, 1 cons
Why You SHOULDN'T Buy HD 600... & What To Get Instead by The Headphone Show — 8 pros, 5 cons
Quick Take: Sennheiser HD 660S2 by Sine Craft Audio — 5 pros, 5 cons
AUDIO ENGINEER Tries the WORLD'S BEST HEADPHONES for the First Time | Sennheiser HE-1 by This is Tech Today — 8 pros, 1 cons
Best & Worst Sennheiser Headphones From Every Generation (Audiophile Breakdown) by Headphones Pro Review — 3 pros, 2 cons

Frequently asked questions

Is the Sennheiser HD 660S2 worth buying?

Based on 23 independent YouTube reviews, the Sennheiser HD 660S2 scores 3.5/5 with 242 positive and 143 negative points mentioned by reviewers, placing it #49 in the Wired Earbuds category.

What do reviewers like most about the Sennheiser HD 660S2?

The most praised aspects are sound quality, value for money, comfort — Sound Quality (150 mentions), Value for Money (28 mentions), Comfort (24 mentions).

What are the most common complaints about the Sennheiser HD 660S2?

Reviewers most frequently criticize sound quality, value for money — Sound Quality (66 mentions), Value for Money (23 mentions).

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