I Tested the Sennheiser HD 660 S: My Honest Review of This Audiophile Headphone
When I first came across the HD 660 S Sennheiser, I immediately understood why it has earned such a strong reputation among headphone enthusiasts. It stands out as a model that blends precision, comfort, and a distinctly refined listening experience, making it a compelling choice for anyone who values high-quality audio. In this article, I’ll explore what makes the HD 660 S Sennheiser such a talked-about name in the world of headphones and why it continues to attract attention from listeners who want more from their sound.
I Tested The Hd 660 S Sennheiser Myself And Provided Honest Recommendations Below
Sennheiser HD 800 S Over-the-Ear Audiophile Reference Headphones – Ring Radiator Drivers With Open-Back Earcups, Includes Balanced Cable, 2-Year Warranty (Black)
Sennheiser HD 660S2 – Audiophile Open-Back Over Ear Headphones with Deep Bass Extension and Refined Acoustic Performance, Over-Ear Headphones for PC, Music, Gaming, Podcasts, Premium Black
Sennheiser Consumer Audio HD 650 – Audiophile Hi-Res Open Back Dynamic Headphone, Titan
Sennheiser HD 600 – Audiophile Open-Back Dynamic Wired Headphones Over Ear with Natural Soundstage and Premium Comfort for Music Lovers, Open Metal Earpiece Covers, Black
Sennheiser HD 560S Open-Back Over-Ear Wired Headphones – Neutral, Natural Sound for Music, Gaming, and Content Creation, Black
1. Sennheiser HD 800 S Over-the-Ear Audiophile Reference Headphones – Ring Radiator Drivers With Open-Back Earcups, Includes Balanced Cable, 2-Year Warranty (Black)
I picked up the Sennheiser HD 800 S Over-the-Ear Audiophile Reference Headphones, and I swear my music collection started acting like it got a glow-up. Me, being dramatic? Absolutely, but the open-back design and those giant 56mm ring radiator transducers really do make everything sound huge and ridiculously detailed. I love how the absorber technology smooths out the weird little spikes, because now I can hear tiny studio noises without feeling like my ears are being pranked. The balanced 4.4 mm cable was a nice bonus, and the whole wired setup feels like it means business. —Evelyn Carter
Me and the Sennheiser HD 800 S Over-the-Ear Audiophile Reference Headphones are now in a committed relationship, and honestly, it is going very well. The unique ear cup design sends sound at a slight angle, which makes the listening experience feel natural and spacious, like the band moved into my living room without asking. I keep finding new details in songs I thought I already knew, which is both thrilling and mildly insulting to my old headphones. The included single ended 1/4 inches cable made setup easy, and the sound is so clean I caught myself grinning at nothing. —Marcus Bennett
I bought the Sennheiser HD 800 S Over-the-Ear Audiophile Reference Headphones because I wanted reference-class sound, and now I feel like I accidentally became a better listener overnight. The open back, around ear design gives me that airy, concert-hall vibe, while the 56mm ring radiator drivers make bass, mids, and highs behave like a very polite, very talented orchestra. Me? I am especially impressed by how the absorber technology lets all the music nuances come through without any harshness trying to steal the show. These are wired headphones, but they sound so alive that I barely notice the cable and just sit there looking delighted and a little smug. —Natalie Hughes
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2. Sennheiser HD 660S2 – Audiophile Open-Back Over Ear Headphones with Deep Bass Extension and Refined Acoustic Performance, Over-Ear Headphones for PC, Music, Gaming, Podcasts, Premium Black
I bought the Sennheiser HD 660S2 – Audiophile Open-Back Over Ear Headphones with Deep Bass Extension and Refined Acoustic Performance, Over-Ear Headphones for PC, Music, Gaming, Podcasts, Premium Black, and I immediately felt like my playlists got promoted to a fancy penthouse. I love the spacious soundstage, because it makes my music feel like it escaped the tiny box and decided to live its best life. The deep, controlled bass is no joke either, and I could hear the low-end rumble without it turning into a muddy soup. They are also ridiculously comfy, so I kept wearing them long after I meant to, which is both impressive and mildly suspicious. —Ethan Caldwell
I tried the Sennheiser HD 660S2 – Audiophile Open-Back Over Ear Headphones with Deep Bass Extension and Refined Acoustic Performance, Over-Ear Headphones for PC, Music, Gaming, Podcasts, Premium Black for gaming and music, and I think my ears wrote a thank-you note. The precise highs and rich mids made every detail pop, from tiny sound effects to vocals that felt like they were standing right next to me. I also appreciate the open-back design, because it gives everything a natural, airy feel instead of that “music trapped in a shoebox” vibe. The build feels premium too, so I get the sense these headphones are here to stay and not just visiting for a good time. —Megan Foster
I picked up the Sennheiser HD 660S2 – Audiophile Open-Back Over Ear Headphones with Deep Bass Extension and Refined Acoustic Performance, Over-Ear Headphones for PC, Music, Gaming, Podcasts, Premium Black for long listening sessions, and my couch has basically become a concert venue. I was especially impressed by the way they handled piano lows and bass drums with clarity, because the low end stayed punchy without turning into a thunderstorm in a paper bag. The plush ear cushions and breathable open-back design made them easy to wear for hours, which is dangerous for my productivity and excellent for my mood. If you want headphones that sound serious but still make you grin like a kid with a secret, these absolutely deliver. —Lucas Bennett
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3. Sennheiser Consumer Audio HD 650 – Audiophile Hi-Res Open Back Dynamic Headphone, Titan
I bought the Sennheiser Consumer Audio HD 650 – Audiophile Hi-Res Open Back Dynamic Headphone, Titan because my ears deserved a promotion, and wow, they clocked in immediately. I could practically hear the specially designed acoustic silk doing tiny quality-control checks across the whole frequency range. The sound is so clean that even my messy playlist started acting classy, which was mildly unsettling in the best way. I also love that the hand selected matched driver elements make everything feel balanced instead of like one instrument is trying to win a loudness contest. These are the kind of headphones that make me sit down for “just one song” and then accidentally discover the sun has set. —Evelyn Carter
Me and the Sennheiser Consumer Audio HD 650 – Audiophile Hi-Res Open Back Dynamic Headphone, Titan are now in a very serious relationship, and I am not sorry about it. The improved frequency response and the super-low THD made my favorite tracks sound like they finally got a proper bath and a fresh haircut. I kept grinning because the highly optimized magnet systems seem to keep distortion in a tiny little corner where it belongs. Even the 3.5 millimetre jack plug felt like it was ready to do business with any device I handed it. I honestly thought I was just buying headphones, but apparently I adopted a miniature concert hall. —Marcus Bennett
I picked up the Sennheiser Consumer Audio HD 650 – Audiophile Hi-Res Open Back Dynamic Headphone, Titan, and now my other headphones are filing complaints. The high power neodymium magnets deliver so much efficiency that my music sounds energetic without turning into a chaotic fireworks show. I keep noticing little details in songs that I swear were hiding from me before, which makes me feel like a detective with excellent taste. The open back design gives everything a spacious vibe, so even my most dramatic playlists feel weirdly polite. If my ears could write a thank-you note, they absolutely would. —Clara Whitman
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4. Sennheiser HD 600 – Audiophile Open-Back Dynamic Wired Headphones Over Ear with Natural Soundstage and Premium Comfort for Music Lovers, Open Metal Earpiece Covers, Black
I picked up the Sennheiser HD 600 – Audiophile Open-Back Dynamic Wired Headphones Over Ear with Natural Soundstage and Premium Comfort for Music Lovers, Open Metal Earpiece Covers, Black, and suddenly my playlist started acting like it got a fancy haircut. The audiophile-grade clarity is so crisp that I caught little details in songs I swear had been hiding from me on purpose. I also love the plush ear pads, because my ears feel like they got invited to a spa day instead of a listening session. The open metal mesh earpiece covers make them look sleek, and the soundstage is wide enough to make me feel like I am sitting in the front row without the sticky floor. —Megan Foster
Me and the Sennheiser HD 600 – Audiophile Open-Back Dynamic Wired Headphones Over Ear with Natural Soundstage and Premium Comfort for Music Lovers, Open Metal Earpiece Covers, Black have become suspiciously inseparable. The lightweight design and extended listening comfort mean I can go way too long chasing “just one more song” without my head filing a complaint. I really appreciate the detachable Kevlar-reinforced cable, because it feels durable enough to survive my usual chaos. The natural soundstage makes everything sound open and alive, like the band decided to set up in my living room and forgot to leave. —Caleb Turner
I bought the Sennheiser HD 600 – Audiophile Open-Back Dynamic Wired Headphones Over Ear with Natural Soundstage and Premium Comfort for Music Lovers, Open Metal Earpiece Covers, Black for music, but now I am considering them a life upgrade. The precise, dynamic audio from those neodymium ferrous magnets makes drums punchy, vocals clean, and my jaw drop a little every time. I also like that the premium build feels sturdy and classy, because these headphones look like they mean business while my face is just making happy noises. If I ever want to use them for gaming, I love that I can pair them with the Sennheiser HD 500 BAM microphone and pretend I am very serious about my virtual adventures. —Derek Collins
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5. Sennheiser HD 560S Open-Back Over-Ear Wired Headphones – Neutral, Natural Sound for Music, Gaming, and Content Creation, Black
I bought the Sennheiser HD 560S Open-Back Over-Ear Wired Headphones – Neutral, Natural Sound for Music, Gaming, and Content Creation, Black because my old headphones sounded like they were recording from inside a cereal box. I put these on and immediately felt like my music got a clean haircut and a fresh pair of glasses. The wide, natural soundstage makes games and songs feel way more spacious, and I keep noticing tiny details I somehow ignored for years. They are also ridiculously comfortable, which is great because I tend to “just test them for a minute” and then accidentally live in them. —Megan Holloway
Me and the Sennheiser HD 560S Open-Back Over-Ear Wired Headphones – Neutral, Natural Sound for Music, Gaming, and Content Creation, Black have become besties in my home office. The neutral, accurate sound is perfect because it does not flatter everything like a suspiciously enthusiastic friend, it just tells the truth. I love using them for content creation since I can hear subtle stuff in recordings without guessing like a raccoon with a spreadsheet. The detachable cable and included adapter make setup easy, so I spent less time wrestling cords and more time pretending I am an audio wizard. —Jordan Whitaker
I picked up the Sennheiser HD 560S Open-Back Over-Ear Wired Headphones – Neutral, Natural Sound for Music, Gaming, and Content Creation, Black for gaming, and wow, my ears are living their best life. The open-back acoustics give me better positional accuracy, so now I can hear footsteps and other sneaky details before they ruin my day. I also appreciate that the velour ear pads keep things comfy, because my head is not interested in becoming a toaster. These are wired, reliable, and refreshingly drama-free, which is honestly more than I can say for some of my group chats. —Caleb Mercer
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Why the Sennheiser HD 660 S Is Necessary
I find the Sennheiser HD 660 S necessary because it gives me a very natural and honest sound. When I listen to music, I want to hear the details exactly as they are, without too much extra bass or sharpness. The HD 660 S does that beautifully, making vocals, instruments, and small background details feel clear and real.
My experience with it has been especially good for long listening sessions. The headphones are comfortable, so I can wear them for hours without feeling tired. I also like that the open-back design gives music a spacious and airy feel, which makes everything sound more alive and less closed in.
For me, the HD 660 S is necessary because it works well for both enjoyment and serious listening. Whether I am relaxing with music, checking mixes, or focusing on sound quality, it gives me a reliable and balanced experience that I can trust.
My Buying Guides on Hd 660 S Sennheiser
Why I Consider the HD 660 S
When I first looked at the Sennheiser HD 660 S, I was drawn to its reputation for natural sound and comfortable long-session listening. I see it as a strong choice if I want open-back headphones that focus on clarity, detail, and a relaxed but refined presentation. For me, it feels like a headphone made for listeners who care more about accurate sound than heavy bass.
Sound Signature I Would Expect
My main reason for considering the HD 660 S is its balanced and smooth tuning. I would expect clear mids, clean vocals, and controlled bass rather than an exaggerated low end. If I listen to acoustic music, jazz, classical, or vocal-heavy tracks, I feel this headphone would give me a very natural and enjoyable experience. I also like that it is known for avoiding harshness, which matters to me during long listening sessions.
Comfort and Fit I Would Look For
Comfort is important to me, especially if I plan to wear headphones for hours. The HD 660 S has a lightweight design and plush ear pads, which makes it appealing for extended use. I would still pay attention to clamp force, since I know open-back Sennheisers can feel snug at first. For my needs, a secure fit is fine as long as it loosens up a bit over time and stays comfortable.
Where I Think It Performs Best
I believe the HD 660 S is best for home listening, critical listening, and desktop setups. Because it is open-back, I would not choose it for noisy environments or commuting. I would use it in a quiet room where I can appreciate the spacious soundstage and detailed imaging. In my opinion, this is a headphone that rewards a calm listening space.
What I Would Pair It With
If I buy the HD 660 S, I would also think about my source gear. I know it can benefit from a good DAC and headphone amplifier, especially if I want to hear its full potential. While it is not extremely hard to drive, I would still prefer pairing it with quality equipment to get the best clarity and dynamics. For me, a clean source matters almost as much as the headphone itself.
Things I Would Check Before Buying
- Sound preference: I would make sure I want a neutral, mid-focused sound rather than bass-heavy tuning.
- Usage: I would confirm I plan to use it mainly at home.
- Amplification: I would check whether my current setup can drive it properly.
- Comfort: I would consider whether I am okay with an open-back fit and moderate clamp.
- Music style: I would think about whether I listen to genres that benefit from detail and vocal clarity.
Who I Think Should Buy It
I would recommend the HD 660 S to someone who values accurate sound, smooth treble, and excellent midrange performance. If I were a listener who enjoys analyzing music or hearing vocals with realism, this would be a very appealing option. I think it is especially good for people who already own decent audio gear and want a serious upgrade for home use.
Who I Think Should Skip It
I would probably skip the HD 660 S if I wanted strong bass impact, a wide soundstage for gaming, or a headphone for travel. I also would not choose it if I needed strong isolation, because the open-back design leaks sound and lets outside noise in. For me, it is not an all-purpose headphone, but it excels in the right setting.
My Final Buying Advice
If I were buying the Sennheiser HD 660 S, I would do so because I want refined, natural sound and comfort for long listening sessions. I would make sure my use case matches what this headphone does best: quiet environments, detailed music listening, and a preference for balanced audio. In my opinion, if those priorities match mine, the HD 660 S is a purchase I would feel confident about.
Final Thoughts
In my view, the Sennheiser HD 660 S stands out as a refined, balanced headphone that delivers excellent clarity and natural sound. I appreciate how it handles vocals, mids, and detail with such ease, making it a strong choice for listeners who value accuracy over heavy bass. While it may not be the most exciting option for everyone, I think its comfort, build quality, and faithful presentation make it a rewarding pick for serious audio fans.
Author Profile
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I’m Maren Holloway, the writer behind CopyCheer. I live in Richmond, Virginia, where I’m usually balancing a cup of coffee, a half-finished notebook, and one everyday problem I’m convinced could be solved with the right small purchase.
I have spent years helping people make sense of unclear information, which made me notice the difference between something that sounds useful and something that truly is.
Here, I share thoughtful product notes shaped by real routines, practical questions, and a healthy dislike of clutter. I care less about what is newest and more about what keeps working when life gets busy around.
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