(NEW) Sennheiser HD 660S2 Wired Audiophile Stereo Headphones
$429.99
$679.95
37% off
Reference Price
Condition: New
Color: Black
Top positive review
80 people found this helpful
Absolutely Great Headphone. Please read.
By Larry M. on Reviewed in the United States on October 1, 2023
There are plenty of opinions on this headphone all over the internet. None are bad, but some are pretty negative. Mainly because from what I am seeing, the reviewers are reviewing the price, not the product. They are saying, you get almost as good performance from model/Brand A or B for less money, focus on the ALMOST. While yes it is true, at $600 is expensive, but make no mistake about it is does out perform other headsets in many areas. This headphone is on sale for $100 more than the HD650, which is $100 more than the HD600, so this falls right in line with Sennheiser pricing structure now, and rightfully so. I don't think it is double or triple the other two 600 series headphones, but it is IMHO is a much better headphone, and worth $100 more. Literally, if you are looking at the 600 or 650's and aren't sure which sound signature is for you, get this one if you have the budget, or wait a little while and save for it... It is worth it. It has the best characteristics of both, which you can see some reviewers stating this. I believe it was Josh Valour who said it, but I do disagree with something he said, it was something along the lines that is in between both models, and a jack of all traits, but master of none. Well, it is a more well rounded performing headphone than both of those and I believe it Masters an overall warm, smooth, well defined, spacious sound with impeccable imaging. For me and my taste it is the PERFECTING SOUNDING HEADPHONE, and exactly what I was looking for. No headphone is the everything to everyone. So be honest with yourself on what you like, based on your ears, and not popular opinions, even if it is from experts, which they are, I am not disputing that at all. I am pretty new to the whole audiophile thing. One thing. But, I have learned that you really need to spend some time with the equipment to let it sink in and let your hearing mature to the product at hand. I realized this, when I purchased the Harmnicdyne athena, reviewers raved about them. It sounded like the overall characteristic I like so I decided to give it a try. I received them, put them on and listened, I was horrified. What I hadn't realized was that my hearing was skewed by listening to the hd560s so much (I really enjoy that headphone). Doing A/b comparisons only made it worse for me. So, I decided to force myself to listen to them. So, I did, I listened exclusively for 2 days, and when I would take breaks and come back and listen to the Athena I was truly amazed at how much I LOVED THEM!!! It is really hard to compare headphones; they all have their own characteristics, just as we all have our own opinions and tastes. So, I believe headphone reviewers have a very difficult job. As some of us expect them to tell us what is "BETTER" headphone A or Headphone B, it just isn't that simple. Headphone A might be better for you, but headphone B is better for me. That is the beauty of this hobby. There is no right, or wrong, better or worse. Just learn to appreciate what your ears tell you and take all other opinions with a huge "GRAIN" of salt. Josh Valour, DMS, The Headphone Show, The Source Audio Video Group, and some others, does a great job of describing the products and giving a sense of how the product is. I watch way too many reviews. LOL. I Hope this helps someone else on the audiophile journey. Here is my current stuff incase anyone care to see. I literally started with headphones and amps a little less than a month ago. The gaming headsets, I have had for about 6months to a year, that is what started it all. I have the HD560s, HD 660s2, Hifiman he400se, Harmonicdyne athena, I am using the IFI Zen air line of products, the Air dac and Air can, both awesome to start with, and you probably won't need to upgrade for some time, key word is need, want is different. lol. For gaming I use the PC38x Sennheiser/epos, the epos H6Pro, Steel series Nova Pro wired with DAC. Sennheiser Game zero, and Audeze PenroseX, Gaming Dacs are the sound Blaster GC7, and G6 love them both but prefer the GC7 in case anyone is looking at the two. Good luck, and good listening!
Top critical review
20 people found this helpful
HD6XX vs HD600 vs HD660s2 | Comparison & Review
By Katun on Reviewed in the United States on May 27, 2025
If you are reading this, chances are you’re stuck in the exact same predicament that many of us find ourselves in at some point, including myself recently. Which HD6** series headphone would suit me best? Despite reading hundreds of forum posts, analyzing dozens of squiggling graphs, and scouring in-depth reviews for that potential “ah-ha!” moment that would convince me one way or another, I still found myself going in endless circles deciding on what to get. I started with the HD6XX due to its ridiculously good price when on sale ($179). With how impressed I was with it on my xDuoo TA-66, I just knew I had to try the others. Naturally, nothing in audio ever seems good enough, and once again I succumbed to the curiosity that something “better” was right around the corner. And now we’re here. The only real difference between the three as far as “what's included” are the cables. HD6XX has a 4.5ft terminated into 1/8th (with adapter), HD600 has a 9ft into a 1/8th (with adapter), and the HD660s2 has two 6ft into a 1/4th and 4.4. HD600’s cable is the thinnest and most flexible, but both the cable and connectors are quite a bit smaller and don’t seem as durable. Other than the extra cable the HD660s2 includes, it also comes wrapped in a microfiber bag instead of a plastic bag like the others (must be where all that extra cost comes in). Jokes aside, physically all headphones are nearly the same with slight variations in frames, color, and swivel. HD660s2 and HD600 have flatter earcup frames whereas the HD6XX is more rounded. The HD6XX also has slightly less swivel range but is less creaky, whereas the HD600 and HD660s2 had a bit more swivel but there was more of an audible rattle when handling or setting down the headphones. Very minor and in no way a flaw, just something I noticed. A word on amplification and gear. I'm using the Topping DX5 as the DAC (sometimes with the headphone out) and the xDuoo TA-66 OTL tube amp. In conjunction with the stock tubes, I’m also testing RCA 6AS7G and 6080 for the rear, and Gold Lion 12AX7 (with adapter) and Voskhod 6N2P-EV for the front. Some combinations I’ve definitely liked more than others, but the stock tubes are FINE! Having owned the HD600 and HD650 many times in the past and heard them on a variety of equipment, after hearing them on the TA-66 I can confidently say these Sennheiser’s really DO need tubes to sound their best. And for $250, I simply cannot recommend the TA-66 enough. I do believe an OTL tube amp is essential for any of these headphones as the sound changes/gains are quite obvious. Match made in heaven. So the adventure began with the HD6XX and the TA-66. I was so overjoyed with this combo and quite honestly, I’ve never heard the HD6XX/HD650 sound this good! My favorite combo was the RCA 6080 and the Gold Lion 12AX7, both waking up the HD6XX and injecting it with more energy. However I was NOT a fan of the RCA 6AS7G as it made them sound really mushy and strained. With how much I was enjoying the HD6XX this time around, I knew I had to get the HD600 once more, having preferred it to the HD650 in the past. To my surprise, I didn’t necessarily… like it more? While the slightly more neutral sound signature was nice for some things, the HD6XX had a more pleasing and likeable tone. The HD600 could sometimes sound a tad thin in comparison. Honestly, both were so close and kept trading blows to the point where I couldn’t choose between them. Thus, the tie breaker is price. HD6XX takes it. Next up, the HD660s2. Having never heard these (or the originals), I wasn’t sure what to expect. I went into it fully hoping that they would be a clear winner with their “extended bass” and other tweaks. I had to do a bit of mental gymnastics to get past the price in comparison to the others ($399 on sale), but I told myself that if they were the tiebreaker and I generally preferred them to the other two that I’d keep them despite representing the worst value of the three. Immediately upon first listen, I did NOT like them! What was this? Bloated bass, darker sound than the HD6XX, a slightly wonky tone, and no noticeable technical improvement in any other area? I was beside myself. This is Sennheiser’s latest and greatest HD6** headphone? First thing that came to mind was the HD700 with Dekoni pads. Was not a fan of those either for the same reason, but at least those were more comfortable and had a larger soundstage. Bass is what you notice first and foremost, and it distracts you from the magic mids. All things considered, the bass isn’t great either. Don’t be fooled into thinking this is a HD600 or HD6XX with “deep bass”. If you want headphones with deep bass, you’d be better off choosing planars or closed-backs. Another way of putting this is to think of the neutral reference HD600 as a “0” on a scale representing its level of bass, treble and sound signature with each sequential number decreasing treble, increasing bass, and sounding warmer. The HD6XX would slot in as a “1”, a little less treble, a little more bass, a little warmer. HD660s2 would then be a “3” as I think the difference from the HD6XX to HD660s2 is larger than the HD600 to HD6XX. The DT880 would probably be a “-1” on this scale, being colder and brighter sounding. Honestly, after following up listening to the HD660s2 with the HD6XX, the HD6XX sounds like it should be the HD660s3, because it “fixes” the flaws I had with the HD660s2. I just don’t get it. HD6XX and HD600 are clearly sidegrades to each other, whereas the HD660s2 is a downgrade in my opinion. Focusing on just the HD600 and HD6XX, these are some of my favorite headphones of all time. Their glorious midrange is still unmatched and I have yet to find a headphone with better tone or timbre. The only other headphone I can recall liking more overall is the HE1000 Stealth. Despite my preference for light bass (I use Magnepan LRS+ with no subs for example and LOVE them), I actually lean more toward the HD6XX than the HD600 which surprised me. I think the HD6XX synergies with tubes a bit more and the sound seems just a little smoother, more cohesive, and more weighty. I think the HD600 is objectively the better headphone, with the HD6XX being subjectively the better one. My brain says HD600, but my heart says HD6XX. Again, very minor differences between them and both are incredible headphones, but the HD6XX is unequivocally the no-brainer simply because of its price. On solid state amps, I find this series can be too mellow, uninvolving, or restrained, but tubes really capitalize on their strengths and are the key to unlocking their full potential. Let’s recap real quick and see the current standing. So we have the HD6XX around $200, the HD600 around $300, and the HD660s2 around $400. The HD6XX and HD600 are too close to call making the extra $100+ not seem like a good investment, yet here we have the HD660s2 which is unquestionably in 3rd place… yet they are DOUBLE the price of the HD6XX? Absolutely not. At the current pricing structure, quite frankly, the HD660s2 is a joke. Do I think the HD600 and HD6XX are $300 headphones? Absolutely. How about the HD660s2? No way. I think they sound like a $200 headphone at best, but based on the HD6XX’s price, I personally would not pay more than $150 for them. By the same token, I also do not think the HD600 is worth $300+ considering the market disruptor HD6XX can be had for $179 or $199. That being said, I don’t think the HD660s2 is a bad headphone. In fact, I still did enjoy it once I got used to it. No doubt its flavor would appeal to some over the HD6XX or HD600 in direct comparison, but I emphasize “direct comparison”. Because at the end of the day, I can’t stress enough just how similar all three of these headphones sound and to just buy whatever is cheapest or most available to you. Case in point, of the many hours I was comparing these three, I can’t tell you how many times I would lose track and literally forget which of them was on my head, only to be blindsided when I pulled them off thinking it was one of the others. This really proved to me that once I started listening, the finer details and small tuning differences faded into obscurity and I was then just listening to a “Sennheiser” headphone. Wrapping up, the biggest discrepancy with this trio of headphones is undoubtedly price and value. So what do I recommend? If you don’t own any of these headphones, get the HD6XX when it's $179, a TA-66 for $249, have some fun rolling tubes, and enjoy the music! The tube swaps provided a bigger sound quality change than switching between any of these headphones and for a whole lot cheaper! And if you already own one of these headphones and are tempted to purchase one of the others hoping for an upgrade or just a different flavor, don’t bother… you only need one HD6** headphone. Famous last words: “you only need one”.
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