Sennheiser HD 660S2 Headphones
Sennheiser HD 660S2 Headphones
Balanced, natural sound with extended bass and plush comfort, ideal for focused listening sessions.
The Sennheiser HD 660S2 headphones are a refined sonic companion for audiophiles craving natural mids and crisp treble without fatigue. Tailored for those who savor focused, at-home listening sessions, these cans deliver an extended bass response that’s precise rather than overpowering, delighting fans of nuanced low-end detail. Experts applaud the plush velour cushions and lightweight build that promise marathon comfort, though some note a firm initial clamp. The open-back design crafts an airy soundstage but limits portability—an honest trade-off backed by user consensus. With a 300Ω impedance demanding quality amplification and versatile detachable cables, value lies in setup savvy as much as price tag finesse.
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Benefits
Trade-Offs
Warm, neutral tuning and refined drivers reduce ear fatigue compared with brighter, harsher models.
Open-back acoustic design causes heavy leakage and minimal isolation; may be unsuitable for shared spaces.
Open-back soundstage and precise imaging improve focus compared with narrow closed-back cans.
300Ω high impedance drivers need external amp; can add device complexity, energy, and portability friction.
Ultra-light aluminum voice coil and low distortion reveal detail without needing loud volumes.
Robust clamping force and headband design may cause pressure or soreness during extended wear.
Velour pads and ergonomic headband support comfortable, longer listening sessions at home.
Dual-entry/proprietary cables limit quick swaps and lack integrated mic; can hinder mobile communications.
Updated transducer and vented magnet design extend sub-bass, supporting fuller, less fatiguing bass reproduction.
Aluminum coils and mixed plastics complicate recycling, unlike eco-leaders using recycled components.
Benefits
Warm, neutral tuning and refined drivers reduce ear fatigue compared with brighter, harsher models.
Open-back soundstage and precise imaging improve focus compared with narrow closed-back cans.
Ultra-light aluminum voice coil and low distortion reveal detail without needing loud volumes.
Velour pads and ergonomic headband support comfortable, longer listening sessions at home.
Updated transducer and vented magnet design extend sub-bass, supporting fuller, less fatiguing bass reproduction.
Trade-Offs
Open-back acoustic design causes heavy leakage and minimal isolation; may be unsuitable for shared spaces.
300Ω high impedance drivers need external amp; can add device complexity, energy, and portability friction.
Robust clamping force and headband design may cause pressure or soreness during extended wear.
Dual-entry/proprietary cables limit quick swaps and lack integrated mic; can hinder mobile communications.
Aluminum coils and mixed plastics complicate recycling, unlike eco-leaders using recycled components.
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Publications
10 LEADING PUBLICATION REVIEWS
Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.
What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.
Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.
What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.
Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.
What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.
Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.
What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.
Dagobiet Morales Alfaro, Vanessa McCuaig, and Yannick Khong from RTINGS highlight the Sennheiser HD 660S2 as a thoughtfully tuned successor to the HD 660 S, delivering a flat and slightly warm sound signature with natural mids and a smooth treble that favors critical listening. They praise its consistent audio delivery, low harmonic distortion, and well-built, comfortable design, though note the high clamping force may cause discomfort for some users. The review emphasizes the headphones’ open-back design, which provides a spacious soundstage but results in poor noise isolation and significant audio leakage, making them unsuitable for travel, office, or sports use. The HD 660S2 require a powerful amplifier due to their increased impedance, and the lack of a microphone limits communication use. Unique insights include detailed measurements revealing stereo mismatch in the bass and a nuanced treble response that may not suit those seeking brighter cymbal detail. Overall, the review conveys a balanced, moderately positive tone, recommending the HD 660S2 primarily for dedicated, quiet listening environments.
What Hi-Fi? highlights the Sennheiser HD 660S2 as a refined and relaxed pair of audiophile headphones that excel in delivering a smooth, captivating midrange, especially for vocal and acoustic music lovers. Praising their comfortable design and lightweight build, the review emphasizes the headphones’ effortless, undemanding listening experience and detailed, intimate vocal reproduction. However, the HD 660S2 show clear limitations in bass performance, with soft, less dynamic low frequencies that lack the punch and tightness found in some rivals like the Beyerdynamic Amiron. This shortfall in bass impact and detail prevents the headphones from reaching their full potential, particularly on bass-heavy or more demanding tracks. Overall, the review conveys a measured enthusiasm, appreciating the HD 660S2’s strengths in midrange clarity and comfort while candidly noting that their subdued bass and limited dynamic drive hold them back from being truly exceptional.
YouTube
11 LEADING EXPERT & INFLUENCER REVIEWS
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
The Headphone ShowResolve from The Headphone Show offers a measured, cautiously positive take on the Sennheiser HD 660S2. He praises its refined build, improved sub-bass extension, and smooth, relaxed tuning that suits certain music styles. However, he finds it less clear and less impactful than the HD 600/650, questioning its value given the higher price and subtle upgrades.
the Honest AudiophileDave from The Honest Audiophile praises the Sennheiser HD 660S2 for its natural, reference-grade sound with extended sub-bass, precise imaging, and exceptional detail retrieval. He highlights its comfort and studio suitability but notes the need for a quality desktop amp and a somewhat intimate soundstage. Overall, he highly recommends it as a balanced, neutral upgrade over previous models.
Social
1 INFLUENCER REVIEW
Nafis ANafis A highlights the Sennheiser HD 660S2’s exceptional sound quality, praising its deep bass, natural and balanced tone, and impressive comfort that surpasses other over-ear headphones. They candidly address the typical open-back drawbacks like audio leakage and lack of noise isolation, emphasizing these are inherent design trade-offs rather than flaws of this model. Overall, Nafis A strongly recommends the HD 660S2 for critical listening in quiet environments like studios or offices, valuing its rich soundstage and tactile comfort despite its unsuitability for travel or noisy settings. The review conveys genuine enthusiasm tempered with practical caveats, making it a thoughtful endorsement for audiophiles seeking premium open-back headphones.
Store Reviews
CUSTOMER REVIEWS FROM 1 STORE
Amazon users consistently celebrate the Sennheiser HD 660S2 headphones for delivering a rich, well-rounded sound that blends the best qualities of the HD600 and HD650 models. Many highlight the headphones’ warm, smooth, and spacious audio signature, praising their impeccable imaging and natural instrument separation that brings music to life—especially classical recordings. Reviewers emphasize how the headphones reveal subtle details and maintain clarity across mids and highs, while some note a slight bass roll-off that can be effectively addressed with EQ adjustments, such as Oratory1990’s preset. Listeners appreciate the comfort of the open-back design, finding the headphones suitable for extended listening sessions, though a few mention the fit feels tight for larger heads or ears. Audiophiles on Amazon also point out the importance of pairing the HD 660S2 with quality amplification, with several recommending hybrid tube amps like the XDUOO TA-10R or Fosi GR70 to unlock fuller dynamics, richer vocals, and a more immersive soundstage. Users observe that the included balanced cable enhances instrument positioning, though some prefer the original cable for deeper bass and clearer dialogue in movies. While opinions on value vary, many users consider the HD 660S2 worth the premium price for its refined engineering and authentic sound reproduction. Some reviewers caution that the headphones’ extended bass can lose control at very high volumes, slightly affecting the listening experience. Additionally, the build quality receives mixed feedback—most find it solid and well-crafted, but a few feel it lacks robustness relative to the cost. The inclusion of two detachable cables earns praise, though cable length and connector durability draw occasional criticism. Overall, Amazon reviewers find the Sennheiser HD 660S2 to be a masterful evolution in the 6xx series, offering a balanced, engaging, and highly detailed listening experience that rewards patient listeners who invest time in acclimating their ears and optimizing their setup.
4.5 Stars / Many verified reviews
Forum Reviews
CUSTOMER REVIEWS FROM 1 FORUM
Reddit users generally view the Sennheiser HD 660S2 as a well-balanced headphone offering improved bass and a warm, pleasant sound signature, making it suitable for long listening sessions and versatile music genres. Many appreciate its comfort, lightness, and portability, though some find the materials feel somewhat cheap. Performance-wise, it is praised for detailed mids and treble clarity but criticized for a narrower soundstage and occasional veiling in the highs. While new buyers often see it as a solid, enjoyable option, some upgraders feel it lacks the refinement or soundstage depth found in higher-end models, leading to mixed opinions on its value at full price.
Many comments
In-Depth Review
Highlights
- •Natural tuningBalanced mids and clear treble
- •Sub-bass extensionEnhanced low-frequency reach and control
- •Comfortable padsBreathable velour cushions for sessions
- •Detachable cablesIncludes 6.3mm and 4.4mm cables
- •Low measured distortionManufacturer testing claims low THD
- •Open-back presentationNatural, unsealed acoustic staging
Considerations
- •High power requirementRequires dedicated amp for best results
- •Durability caveatsMixed reports on robustness
- •Limited portabilityOpen-back and no wireless features
- •Initial clamp fitCan feel snug before break-in
- •Soundstage limitationsNot the widest stage; some veiling
- •Basic protective accessoryShips with plastic carry pouch only
Sennheiser’s HD 660S2 headphones build on the brand’s storied legacy with a focus on delivering balanced sound quality that blends natural mids and crisp treble. Designed primarily for audiophiles and studio enthusiasts, they offer an extended bass response through a redesigned coil, reaching deeper low frequencies without overwhelming punch. Comfort is prioritized via lightweight construction paired with plush velour ear cushions, making long listening sessions less taxing. The headphones demand attention to amplification needs due to their 300-ohm impedance, so pairing them with quality DACs or amps unlocks their full potential. Their modular design includes detachable cables supporting both standard and balanced connections, enhancing versatility in setups. While the build balances durability and elegance crafted across Germany and Ireland, it leans toward lighter materials that may feel less robust than heavier competitors. If you appreciate sonic precision married to practical comfort, these cans warrant a closer look at what follows—where each feature plays its part in this finely tuned performance symphony.
Comfort & Fit
Slip on these headphones featuring plush velour ear cushions designed for breathability during long sessions, combined with a lightweight frame around 240-260g to minimize fatigue. The fit is generally snug but may feel tight initially due to firm clamping force—a trade-off ensuring solid acoustic seal and immersive listening. Users praise comfort yet caution larger heads might need break-in time or alternative pads.
Bass Extension / Low-End Response
The revised coil lowers resonant frequency from 110Hz to 70Hz, pushing sub-bass extension further down by roughly 5-6dB gain in lowest octaves—translating into richer lows without muddiness. This isn't your typical thumping bass; instead, expect articulate depth perfect for piano lows and nuanced kick drums, making it ideal for listeners seeking controlled power rather than overwhelming boom.
Build Quality & Materials
Crafted across Germany and Ireland using quality materials like aluminum housing components offers elegance paired with durability—but don’t mistake lightness for fragility; some reviewers mention less robust construction compared to heavier premium rivals. Detachable cables add repairability benefits while plastic carry pouch keeps things minimalistic on protection.
Sound Quality
Dive into the sonic world with 42mm dynamic drivers sporting an ultra-light aluminum voice coil, delivering a natural midrange and clear treble that audiophiles crave. The open-back design crafts a spacious soundstage, though some users note it’s not the widest in its class. With low total harmonic distortion under 0.04%, expect detailed clarity without harshness. While bass is extended deeper than predecessors, it's more about precision than slam—ideal for those who appreciate balance over bass-heavy hype.
Impedance / Amplification Requirement
With a high impedance of 300Ω, these headphones demand proper amplification to shine fully—the brand recommends pairing them with dedicated DAC/amps rather than plugging straight into smartphones or casual devices. Without clean power delivery, their detail retrieval and dynamics can fall flat; thus this model suits desktop setups better than mobile convenience seekers.
Conclusion
Sound quality here is the star, boasting natural mids and crisp treble that invite detailed listening sessions. Comfort shines with breathable velour cushions and a lightweight frame, though initial clamp pressure might test patience. The bass dives deeper than before—offering articulate low-end extension without sacrificing clarity—a feature some listeners prize for its precision over punch. Build materials balance elegance with lightness but may leave durability-conscious users wishing for more heft. Their 300-ohm impedance demands quality amplification, nudging casual users toward dedicated gear to unlock full potential. Meanwhile, flexible detachable cables supporting balanced connections add versatility rarely seen at this tier. These headphones reward those seeking sonic refinement paired with practical comfort but aren’t tailored for on-the-go use or wireless convenience lovers. In essence, they carve out a niche where focused performance meets thoughtful design—a pairing that justifies their place among discerning audiophiles willing to invest in sound’s subtle art form.
Feature Scores
This reflects reviews and ratings from established critics, journalists, and users who have evaluated the item. Their opinions provide a comprehensive assessment.
Performance
Sound Quality
4/5
Noise Cancellation Effectiveness
5/5
Battery Life
TBD
Value
Price-to-Performance
4/5
Warranty
3/5
Included Accessories
4/5
Design
Comfort
4/5
Build Quality
4/5
Controls
1/5
Health
Hearing Protection
2/5
Material Safety
4/5
Hygiene
3/5
Safety
Battery Safety
5/5
Regulatory Compliance
3/5
Physical Hazards
4/5
Sustainability
Recyclability
3/5
Sustainable Materials Use
2/5
Packaging Sustainability
4/5
Experience Style
Customization
4/5
Multi-Device Pairing
TBD
Ease of Use
4/5
Specifications
This section outlines the product's key facts, covering essential features, details, dimensions, materials, and any unique characteristics that define its functionality and usability.
Performance
Value
Design
Sustainability
Experience Style
Frequently Asked Questions
3 Questions
Find Yours
What kind of sound profile do you prefer in your over-ear headphones?
Answer to find your best matches.
