Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
Product Strengths
- Very comfortable for long listening sessions thanks to its light weight and soft velour earpads
- Sturdy and reliable build quality
- Provides excellent detail and transparency, with an overall natural timbre
- Easier to drive than other HD 600 series headphones due to its lower impedance and higher sensitivity
- Detailed, balanced mid-range
Product Considerations
- Narrow soundstage
- Included cables are very long, and can be awkward to use on a desktop
- Lacking bass extension, rolling off aggressively around 80Hz
- The peak at 5.5k might make these sound a little unnatural
Comparisons (according to reviewers)
- Vs. HiFiMan Sundara: The Sundara is considered better overall, with at least as good detail retrieval, better speed, better dynamic impact, better bass extension, and a considerably better soundstage
- Vs. Sennheiser HD 6XX/650: Detail retrieval is not particularly better
- Vs. Sennheiser HD 580: The HD 580 is significantly more neutral
- Vs. Sennheiser HD 600: The HD 600 has a slightly clearer sound, thanks to the comparative extra energy in the upper midrange
- Vs. Beyerdynamic DT 990 PRO: The Beyerdynamic have a slight peak in the low-the mid-treble that can add sharpness to sibilants, whereas the Sennheiser sound more veiled in this range
Takeaway: The HD 660S is a comfortable and well-built headphone that provides a natural and detailed sound, making it great for critical listening and long listening sessions. It is easy to drive, making it accessible to a wide range of audio setups.
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reviews

Manufacturer details
- Frequency response: 9 Hz - 41,500 Hz
- Sound pressure level (SPL): 104 dB (1 V)
- Impedance: 150 Ω
- Driver size: 42mm
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
Select products
HD-559
- Positioning: Entry-level design focused on affordability and everyday listening needs.
- Description: Offers clear sound and comfortable design with a straightforward acoustic setup suitable for small rooms and casual music enjoyment. Compared to the HD-560S and HD-660S2, its basic performance and limited feature set make it a better fit for buyers with lower budgets and simple functionality needs.
HD-560S
- Positioning: Mid-tier model balancing cost and improved technical performance.
- Description: Delivers enhanced clarity and precision with a refined tuning approach that benefits home or studio use. When compared with the HD-559 and HD-660S2, it provides better sound detail while remaining accessible for buyers seeking moderate cost and practical functionality.
HD-660S2
- Positioning: Mid to high-level design crafted for a richer and fuller sound experience.
- Description: Offers a warmer sound signature with improved bass impact and a wider soundstage. Relative to the HD-560S and HD-800S, its technical enhancements and superior build quality justify the higher investment for users aiming for more refined performance without reaching the premium flagship tier.
HD-800 S
- Positioning: High-end open-back design intended for detailed, analytical listening applications.
- Description: Provides natural, transparent sound with a wide soundstage and precise imaging that benefits critical listening in controlled environments. Compared to the HD-660S2 and HD-820, it emphasizes technical accuracy and spatial detail.
HD-820
- Positioning: Premium closed-back design engineered for reference-class listening in isolated environments.
- Description: Features a unique closed-back design that merges open headphone sound characteristics with enhanced bass warmth and improved isolation, suited for quiet and nearfield environments. In comparison with the HD-800 S, it prioritizes sound isolation and versatility over the expansive open-air presentation.
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Used
Sennheiser
What if you spend more?
Product Strengths
- Improved bass response compared to the original HD 660S and other HD 6XX series headphones adds warmth and a richer, fuller sound
- Lightweight design (around 260g) and comfortable earpads make them suitable for extended listening periods
- Detailed and nuanced sound, with a well-balanced midrange and smooth treble, provides a clear and crisp listening experience without being overly analytical
- Precise imaging allows for accurate instrument placement and a good sense of sound direction
- It comes with both 4.4mm balanced and 6.35mm single-ended cables, providing connectivity options for various sources
Product Considerations
- Some feel the price is high for the level of upgrade compared to the original HD 660S, especially with other competitive options available
- While the bass is improved, it's not a bass-heavy headphone and might not satisfy those seeking a thunderous bass response
- The clamping force can be a bit tight out of the box, which may cause discomfort for some users
- The soundstage isn't exceptionally wide, which may not be ideal for those seeking a very spacious and out-of-head experience
- The build quality, while durable, does not feel as premium as other headphones in the same price range due to the extensive use of plastic
Comparisons (according to reviewers)
- The HD 660S2 is generally considered an improvement over the HD 660S, primarily due to the enhanced bass response and slightly smoother sound
- The Sivga SV023 offers a brighter, crisper sound for less money, while the HD 660S2 provides a fuller, more vocal-oriented sound
- The Harmonic Dyne G200 is more exciting and energetic, but has a less natural tonality and may be less comfortable
- The Meze 109 Pro is a better headphone in almost every way, but it is more expensive and may be a little sibilant for some listeners
- HD 660 S2 offers better sub-bass reach and imaging, but the Sennheiser HD 650 still remains unmatched for male vocals
- The HIFIMAN Edition XS sounds bigger, deeper, and wider, while HD 660S2 is more about the tonality
Takeaway: The HD 660S2 is a comfortable and well-rounded headphone with a more balanced and enjoyable sound signature than its predecessor, especially with its improved bass response. It's a great choice for those who appreciate a smooth, detailed, and easy-to-listen-to headphone for various genres.
Video review
Our take on the brand
Product Strengths
- Unique octagonal design made of quality materials, with a rugged, serviceable build quality featuring exposed nuts and bolts.
- Surprising amount of bass for an open-back, on-ear headphone, that is solid, tangible, present, well balanced and well tuned.
- The silver-plated OCC copper cable is lightweight, pliable, ergonomic and does not remain bent after staying still.
- Comfortable on-ear headphone, especially considering it's an on-ear design, with thick, soft pads and a comfortable headband.
- Easy to drive with portable devices like dongles or smartphones.
Product Considerations
- Being an on-ear design, the Thalia can become uncomfortable after extended listening sessions (45 minutes or longer) due to pressure on the ears.
- Not the most compact headphone, and does not fold up, limiting its portability somewhat.
- The open-back design results in sound leakage, making it less suitable for noisy environments or situations where discretion is required.
- The height adjustment mechanism, while providing fine control, is a bit fiddly and not easily adjustable on the fly.
- Its lower-midrange will be too full for some.
Comparisons (according to reviewers)
- The Thalia is far superior to the Koss Porta Pro and sets a new standard for portable on-ear headphones, but it is inspired by the Porta Pro.
- Compared to the Grado RS2x, the Thalia is more durable, comfortable, and more enjoyable overall, and is more bassy and thicker in the midrange.
- The Thalia has a faster pace and a better driver control, and offers a lot more in the top-octave than the Sennheiser Momentum 2/3.
Takeaway: The Thalia is a uniquely designed, portable on-ear headphone that delivers great sound and is built to last. It is a good option for those who want a distinctive headphone that is fun to listen to.
Video review
Our take on the brand
Our summary
Product Strengths
- Uses premium materials like carbon fiber, metal, sheep lambskin earpads, and zebra wood faceplates for a luxurious feel, with excellent build quality
- Has a mostly neutral sound signature, with lambskin pads bass response is very good with a tasteful emphasis placed on the sub-bass region, and a decent midrange
- Provides good detail retrieval, resolution, and transparency of sound, the drivers can show plenty of information and micro detail
- A pad swapping system allows changes to sound characteristics, with lambskin pads and breathable fabric pads included
- Comes with a quarter-inch adapter and a 4-pin XLR adapter for use with portable or desktop devices
Product Considerations
- The stock cable is 3 meters long, which is too long for desktop use
- Headband adjustment can be a little stiff to move
- With leather pads, the highs can get slightly sharp
- There is a slight sharpness in the upper treble that might pose a problem for some listeners, using fabric pads can mitigate this
- Weight distribution could be better, there's not enough padding on the headband, and the clamp force is low, this distributes all the weight across the top of the head, which can be bothersome after 40-50 minutes
Comparisons (according to reviewers)
- Vs HiFiMan Susvara: Has a similar driver structure
- Vs HiFiMan HE1000 Unveiled: Is close in terms of technical performance like resolution, transient response, soundstage, depth, and openness
- Vs HiFiMan Arya Stealth: Has a better build quality and bass response
Takeaway: The FiiO FT7 is a well-built, comfortable headphone that offers a neutral-leaning-warm sound that can be tailored with different earpads. The FT7 competes with other headphones that cost significantly more, making it a great pick at its price point.
Video review
Our take on the brand
Product Strengths
- Excellent stereo separation for mixing and monitoring
- Built with aluminum, it has a durable feel
- Designed for reference listening
- Clean, linear, and very detailed mids
Product Considerations
- Sound can be considered somewhat restrained, lacking upper midrange and low to HF 'hype'
- Cloth ear pads may not feel as soft or luxurious as velour pads on some other headphones
- Lacks impact and bite
- Headband padding is uncomfortable
- Single-entry cable is on the right side, which is an unusual placement
Comparisons (according to reviewers)
- Vs Sennheiser HD650: Differences come down to something similar to a full-range studio monitor versus a full-range hifi speaker of equal build quality and similar design, Sennheisers are geared more towards enjoying the brain-pleasing sounds of music, while you probably want to mix with the Neumanns
- Vs Sennheiser HD600/650: The HD600 and HD650 are more comfortable, with a better industrial design than the NDH-30
Takeaway: The Neumann NDH 30 is a tool that can be very helpful for mixing sessions, especially for identifying details in the mid-range of a mix. Its design and build quality also make it a lasting product.
Video review
Our take on the brand
What competes at this price?
Our Summary
Product Strengths
- The HD 560S delivers a flat sound profile that should suit most musical genres
- Very comfortable, with a relatively lightweight design and plenty of plush padding
- Soundstage is exemplary
- Lightweight and provide a nimble feel
- Excels in delivering both vocals and instruments with a remarkable level of clarity and precision
Product Considerations
- Some users might find it a bit dull over time due to its conservative sound signature
- Can be a bit intense at times in the lower treble
- The plastic construction does not scream luxury
- Some loss of texture in the mid-bass, with bass notes of different instruments often sounding the same
Comparisons (according to reviewers)
- Vs AKG K702: 560S' sound is going to feel a bit closer, but it may not always be a good thing when trying to hear what is farther off in the distance, for gaming
- Vs Sennheiser HD58X: The 560S is cleaner and more accurate sounding than the HD58X
- Vs Sennheiser HD600: The 560S is more intimate and livelier sounding than the darker HD600
- Vs HIFIMAN Sundara: Compared to the more expensive Hifiman Sundara, the 560S sounds like it lacks detail across the frequency spectrum, except in the sub bass region where the Sundara does not seem to dig as deep
Takeaway: The Sennheiser HD560S is a comfortable headphone with a well-balanced sound, making it a solid choice for both gamers and music enthusiasts looking for neutrality and clarity. It is a versatile headphone for various genres and applications.
Video review
Our take on the brand
Our Summary
Product Strengths
- Reviewer's favorite midrange tuning from Sennheiser
- Better bass extension than HD 6 series, and less upper-midrange glare than HD 505
- Upper treble works well, similar to HD 505
- Homogenous, neutral sonic presentation
- Low weight and small caliper pressure make it extremely comfortable
Product Considerations
- Lower treble is, like HD 505, rather scratchy and dry sounding
- Same uncomfortable headband as the HD 505
- Soundstage could be wider and deeper
- Not the most exciting look
- Like all open-back headphones, the Sennheiser HD 550 does not attempt to isolate from surroundings
Comparisons (according to reviewers)
- Vs FiiO FT1 Pro: Both share a similar treble character, but the HD 550’s is less apparent due to the upper-midrange being considerably more present
- Vs Sennheiser HD 560S: The HD 550 fixes every major tonal issue with the HD 560S, while having a more even dynamics presentation and better comfort
- Vs Sennheiser HD 490 Pro: HD 550 does away with incrementalism, goes full-send with an industry-leading midrange tuning, fixes almost all issues with HD 490 Pro’s treble, all while keeping the same level of bass extension at a lower price
- Vs Sennheiser HD 505: The reduction between 2-5 kHz does the HD 550 a ton of favors when it comes to making the headphone more versatile across genres
- Vs Sennheiser HD 600 and HD 650: HD 550 has more bass extension than HD 600 and 650
- Vs HIFIMAN Sundara: If more mass is acceptable, and more repairability is desired, the HIFIMAN Sundara are a great pick
Takeaway: The Sennheiser HD 550 offers a balanced and enjoyable listening experience, making it a solid choice for both audiophiles and everyday music listeners, especially those looking for something comfortable. With its user-friendly design and appealing sound profile, it is a great option to enhance audio enjoyment.
Video review
Our take on the brand
Our Summary
Product Strengths
- Nicely balanced, upper-midrange focused sound profile
- Very well built for the price
- Easily driven from dongle DACs and game controllers
- Versatile, and is great for all genres of music and for both casual and competitive gaming
- Perfect as a gateway headphone for those looking to get into the audio hobby
Product Considerations
- The top of the headband may cause a pressure point for some
- It has a proprietary 2.5mm locking connection
- The sound profile may be too boring for those who already own several headphones
Takeaway: The HD 505 Copper Edition is a versatile, easy-to-drive headphone that sounds great overall, making it a good choice for new audiophiles or gamers. It offers good value and a balanced sound signature for the price.
Video review
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Our Summary
Product Strengths
- Excellent resolution and imaging capabilities
- Features a nanometer thickness diaphragm and Stealth Magnet design that improves transient response and lowers harmonic distortion
- Easy to drive, it is among the most efficient open-back planar magnetic headphones on the market right now
- Features a tight, textured, and clean bass response
- Good detail retrieval and vocal clarity
Product Considerations
- Treble might be too much for some listeners
- May not be the most lively in macro-dynamics
- Reviewers note a slightly dry timbre
- Lean, slightly cold mid-range
- The included 3-meter cable is not useful for desktop use
Comparisons (according to reviewers)
- Similar to the Meze 109, but a planar
- Sounded a little bit more hifi than the Austrian Audio Hi-X 65
- Has a more warm, natural feel than the original Ananda
- Easiest to drive when compared to the Edition XS
- Superior in technical performance when compared to the Hifiman Sundara
Takeaway: The Ananda Nano is a well-tuned headphone with superior resolution and marvelous timbre, particularly good for electronic music and those who care about vocal clarity. It's a planar alternative that’s incredibly fast and detailed, with excellent imaging and soundstage.
Video review
Our take on the brand
Our Summary
Product Strengths
- Beautifully made with real wooden cups, nice metallic flourishes, and a nice adjustment system
- Very easy to drive from any device due to its 32 ohm impedance and 103 dB sensitivity
- The included hard case is of good quality and protective
- Comfortable to wear for extended sessions due to its light weight (296g) and well-designed headband
- Good soundstage width and overall space, with well-defined instrument separation
Product Considerations
- Some reviewers with larger ears may find the earcups to be too small, causing discomfort
- Lack of extra treble detail and energy means that some percussion misses its snap and shimmer
- The headband size is pretty small, so if your head is on the large side, it might not fit
- Stock earpads are too shallow for some users, causing their ears to touch the inside of the cups
- The midrange can sound stuffy and veiled, lacking clarity and detail compared to some competitors
Comparisons (according to reviewers)
- Vs Monolith M1060 V2: The Phoenix has better quality treble, but the M1060 has a better quantity of treble and a more neutral sound
- Vs Sennheiser HD560S: The HD560S is a reference headphone designed to be analytical and neutral, while the Phoenix is colored, engaging, rich, and warm
- Vs Sennheiser HD600: The Phoenix is warmer, has deeper sub-bass extension, and a wider soundstage, but the HD600 is more intimate, clear, and detailed in the mids and vocals
- Vs beyerdynamic DT880: The DT880 has a midbass bump and clearer mids, while the Phoenix has better treble extension
- Vs HarmonicDyne Zeus: The Zeus is a warmer set, but the Phoenix is better implemented
- Vs Austrian Audio Hi-X55: The Phoenix has a more environmental feel when it comes to its sub-bass response and a wider soundstage, but the Hi-X55 has a sweeter vocal presentation
Takeaway: The Phoenix offers a warm, rich, and punchy sound signature in a beautifully designed and comfortable package that is easy to drive. It could be a great option for those who enjoy a bass-emphasized sound and listen to genres where extra bass is beneficial.
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