











🎶 Elevate your audio game — hear what others miss, feel what others don’t.
The Sennheiser HD 660S2 wired headphones combine advanced 42mm airflow-optimized transducers and a 300-ohm ultra-light aluminum voice coil to deliver natural, relaxed, and high-fidelity sound with deep sub-bass impact. Featuring an open-back design for breathability and comfort, these headphones offer a wide frequency response from 8 Hz to 41.5 kHz, making them ideal for audiophiles and professionals seeking studio-quality sound with exceptional clarity and immersive low-end presence.












| Age Range Description | Adult |
| Antenna Location | music |
| Asin | B0BRT1ZN7Q |
| Audio Driver Size | 42 Millimetres |
| Audio Driver Type | Dynamic Driver |
| Best Sellers Rank | 22,613 in Musical Instruments & DJ (See Top 100 in Musical Instruments & DJ) 136 in Studio Headphones |
| Bluetooth Version | 5.0 |
| Box Contents | HD 660S2 headphones, 6.3 mm cable (1.8 m), 4.4 mm cable (1.8 m), 6.3 mm to 3.5 mm adapter, Carry pouch |
| Brand Name | Sennheiser |
| Cable Features | Detachable |
| Colour | Black |
| Compatible Devices | Smartphone |
| Control Method | Touch |
| Control Type | Media Control |
| Customer Package Type | Protective delivery packaging with a portable carry pouch |
| Customer Reviews | 4.5 4.5 out of 5 stars (720) 4.5 out of 5 stars |
| Earpiece Shape | over_ear |
| Enclosure Material | Aluminium |
| External Testing Certification | nao aplicavel |
| Frequency Range | 8 Hz - 41.5 kHz |
| Global Trade Identification Number | 00810091270370, 04260752330374 |
| Headphone Form Factor | Over Ear |
| Headphone Jack | 1/4 inch TRS, 4.4 mm TRRRS |
| Headphones Ear Placement | Over Ear |
| Impedance | 300 Ohms |
| Item Weight | 0.3 Kilograms |
| Manufacturer | Sonova |
| Model Name | HD 660S2 |
| Model Number | 700240 |
| Network Connectivity Technology | Wired |
| Noise Control | Sound Isolation |
| Number Of Items | 1 |
| Product Features | stereo pairing |
| Series Number | 700240 |
| Specific Uses For Product | Music |
| Style Name | Headphones |
| Theme | Music |
| Unit Count | 1.0 count |
| Water Resistance Level | Not Water Resistant |
| Wireless Technology Type | Bluetooth |
User
Not worth the hype
Well…a few hours in and let’s say I am not overwhelmed. Very little difference between these and XM5s and maybe not so good. Returning.
User
truely cheap truly crap
the original hd650 is 10 times better , bass cannot hold , was in a cheap boxdont buy them
User
Du pur Sennheiser
Son exceptionnel
User
It's magic: enter the concert hall
Update on August 9, 2024:The iFi DAC combined with the iFi Zen Can produced clear sound and proper dynamics, but human voice sounded feeble and harmonics were missing (that is, a concert piano sounded like an electronic one).I figured it was the amplifier, not the headphones, so I gave a try to an XDUOO TA-10R, which is a hybrid headphone amp, using a balanced tube and Class A amplification (USB, optical, RCA, and coax inputs, a pseudo-balanced output that still sounds better than the 6.3mm unbalanced one). Once I swapped out the factory tube for a Gold Lion, the sound stage opened up, human voice became full, and the harshness around the high C vanished. Even poor recordings (uncompressed) sound good, providing a lot more presence than I experienced from the iFi combo. The fullest sound that goes deepest uses a Tungsram tube.I must admit that a $40 Koss would probably meet most people's need.Also, as my old friend said about 50 years ago, no headphone can compete with a good room setup (which can be hilariously expensive, but not necessarily. Compiling it from used items, you can get one for around $10k, which is still a lot less than the top-of-the-line headphones that still can't compete with it.Original review from May 24, 2024:Every time I put them on, I feel mesmerized. Have never had this experience with any other headphones; it's like the music comes to life around my head, as if I was present at the performance. Granted, that applies mostly to classical music, and the sound can easily bring tears into my eyes.Still, these babies produce excellent sound for everything I've put on them. I'm not a gamer, so I can't comment on the gaming performance, but there is at least one 5-star review on that subject.Anyway, beyond the subjective, sources and recordings are also essential to consider as well as the connections, so let me submerge into those details.Good headphones are no good for compressed sound, but plenty of headphones are made for such a clientele. The s2 with its refined sound is targeting an audience that cares for the original sound.Please, notice that when people "burn in" new equipment, during much of that (except for diaphragms in speakers), what happens is that the components adjust to each other, especially on the analogue side. The outcome ultimately determines if their combination is feasible or not. My current setup has been serving me well in the last five years or so, so I haven't made any changes.I used an iFi Zen DAC v1 (from the USB port on computer) and an iFi Zen Can v1 (on the RCA input from a relatively high-end LG Blu Ray player from the optical port through a digital-to-analogue converter). Connected the DAC with the amp through their balanced ports with a short decent balanced cable. Both amps were hooked up to the sources with SVS interconnect cables. Didn't use the "Trubass" feature on either one, because for my taste, it upsets the sound balance (the DAC also amps the bass at a higher frequency than the amp). My sources were the usual high-resolution recordings (both pop and classical) and Blu Ray movies I use for testing new components.The most prominent strengths of the s2 is extended bass and an adherence to the original sound signature. While the OEM cables are fine, out of the two supplied, I favor balanced one. I have found a purchase for a previous Sennheiser that didn't work out at the time giving me better resolution. Amazon is still selling it: KK Cable II-SO. (Added on 6/28/24: for movies, the original balanced cable works better; the KK produces less bass in return for better instrument positioning, and dialogues suffer from human voice being elevated around 500Hz, which makes conversations harsh and unpleasant to listen to. The original cable goes deeper, although perhaps a bit muddied in the lowest end, but conversations are clear). The only problem with the extended bass is that the housing loses a little control over it beyond a certain (obviously VERY high) volume, so I can sort of feel the ear cups moving, which breaks the illusion of being present. This is probably the main reason why the pressure around the ears is relatively high (and loosening it might not be the best idea).The s2 might not be the best for someone with a large head (it might feel uncomfortably tight) or unusually large ears that the ear cups cannot cover, and it took me a few days to get used to it, because I am on the high end of average head and ear sizes.The included bag is a plastic dust collector; I am using an anti-static bag instead. Hard cases are available for transportation, but the original box works for that, if only on occasion.As opposed to the planars I've heard (Moondrop Para and Hifiman HE400se, but others report the same problems with lot costlier planars), the s2 retains the familiar sound on the recordings I usually use for testing new equipment, and it extends the listening experience in gentle, but important ways. The bass reverberates in the concert hall, and is not victim to extensive channel separation. Even harmonics play the same or better than on anything else I've heard in this price range or below, although this is a feature that can warrant higher investments. No problem with high-pitched human voice being harsh and sibilants don't suppress other frequencies; the performance is actually toned down a bit in order to retain the sound that recordings must have been meant to sound like. In my understanding "warm sound" is often used for describing the feature, perhaps because no highs and mids dominate at the expense of the bass or each other. Despite the somewhat reserved (but not veiled) presentation, the dynamics don't suffer.I believe, the secret is ingenious engineering that uses physics: the proper driver and built-in sound paths in the earphones. Many other headphones have built-in electronics in the sound path, allegedly, to protect the user's hearing, but to me, it seems more like protecting the drivers from overload. Consequently, the s2 doesn't clip at low bass (emit a clicking sound, while cutting out the sound), while most the sound is there in that region, too. The headroom is like sitting in the concert hall, albeit a bit further in the back that the eight row, but the sound image remains steady at various volume levels. To me, the harmony and the unity of the sound, along with the original sound signature, is worth the price.Added on 04/03/25:The best cable I've found for these is https://www.amazon.com/gp/product/B0BZMS68RV, although it lasted only for six months. The best amplifier in this price range is a hybrid tube (the tube is only for buffering a Class A headphone amp) is the XDUOO TA-10R.Added on 12/22/25The best affordable tube headphone amp for these turned out to be a Fosi GR70, available on Amazon, where I also bought it for under $180.
User
مقبوله ماهي الافضل فيه افضل بكثير وفيها اصوات غريبه
السماعه وصلتني خربانه اتوقع اذا حركت راسي او شي احس في طقه في السماعه من على اليسار مع اول يوم مع انها ماصار فيها اي شي من اول مافكيتها من الكرتون اتوقع من الشحن او خطاء مصنعي والله مدري + الاصوات مو افضل شي والله تحس الاصوات مكتومه وما تستاهل سعرها ابد سنهايزر فيها مشكله كل الاجيال الجديده خايسه خلك على القديم HD 600 650 هم الافضل من ناحيه كل شي وخاصه الاصوات والراحه ذي يمكن انصحك تشتريها لو سعرها 900 او 1100 بالكثير بعد خيبت ظني الشركه ودافع بسماعه 1900 وتطلع اصوات اذا حركت راسي انصدمت والله والكرتون حق المنتج وصلني مخدش وفيه طعوج من الشحن اتوقع الي صار لي من الشحن الزبده نصيحتي بعد بحث وكذا SENNHSAIR HD 600 و 650 افضل شي صدقني
User
Gutes Gerät
Typisch Sennheiser sehr gute Qualität
User
Fantastic headphone
Ok.The Skinny of it...A little rough in the edges but..still acceptable by listening standard.Compared to AT WP 900 this model is on the softer side and rougher on the highs.Compared to Grado SR60 the sound is compressed with this headphone.Compared to Sony MZR 2 the 1k version that is opened and not compress but you feel you want to play it louder. But no complains if you want to pamper yourself.Finally compared to the top of the line Focal 6k model. This one is bar none. Dynamics highs mid and tonal separation this is serious stuff. But Seriously all running on the same LG V60 as source with Tidal and with USB audio pro meaning it is forced to output 16bit. Not 48....Final word for the price...we have to be fair for the quality of sound on the price. If you were to compare it with the AT WP900 same price but now with the promo the Senheiser is reasonable value for money. Atleast if you are thinking about giving this to your teenage kids.Fine with it. No complaints. Cause if you look at it in this way every 6months they will end up buying new cans. Cause the wires just snap but with the Senheiser you can easily replace them. All the parts sponge head sponge and the cables you can swap them when wear and tear approaches.Besides you only have 1pair of ears so either you take good care of them for the better part of your life or you end up loosing to be deaf as time and age passes by. Your choice. For me I will this model. It is fine for daily use.Reasonable.
Trustpilot
1 month ago
1 month ago