(The Flagship) Sennheiser HD 660S2 - Headphone Highlights

The HD 660S2 sits as the current flagship headphone of Sennheiser's 600 series line. Now that I have the opportunity to examine the HD 660S2 in a controlled environment rather than just on a showroom floor, we can critically examine what unique properties the headphone adds to the 600 family, and answer the question of if it deserves the flagship crown that it wears.
Sennheiser HD 660S2 - amzn.to/3u3eSFK
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Chapters
0:00 What is a flagship?
2:00 Build
9:07 Accessories
12:22 Comfort
14:45 Sound Performance
24:50 But is it Really a Flagship?
26:50 Closing Thoughts
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#audiophile #headphones #reviews​ #sennheiser #hd660s2 ‪@sennheiser‬

[@tomdavis6371]

Very nice review, and I can fully agree with everything you mention, for the most part. My Sennheiser affiliation began in 1998 when I plunked down nearly $500 to buy the HD600, an ungodly amount of money to spend on a pair of headphones I thought. But I wanted a GREAT sounding pair and at the time they were as good as it got. I splurged on them because I was working a second shift job at the time and returning home each night at around 12:30 am to a sleeping wife. I couldn't turn the stereo on with her next door. So in 1999 my wife and I had a child, an autistic son, and one day as he was about to turn one and was just on the verge of learning to walk, he pulled himself up enough using my roll top desk to get his meat hooks on my headphones, which I had failed to put up out of his reach. By the time I discovered them missing the next morning they had wound up in the bottom of the dishwasher, apparently he had taken them down the hallway while crawling and caught his mother off guard with the door open. It didn't turn out well. I didn't buy another pair of 600's until about seven years ago but I currently own the 600/6XX and 660S2. I love them all but at this point the S2 is my favorite. By far. I'm 62 years old now and I find the elevated upper register very pleasing, not at all sibilant or overbearing. I get the sense that it helps to eliminate the notorious Sennheiser veil. The top end sounds so much cleaner to me. The mid-range has always been the star of the show with this series but with the bump in the bass of the S2 I find the overall presentation more enjoyable, more complete. You're right in that there is more information being presented. I use a Burson Audio Conducter 3 Performance combo on the solid state side, along with a 1st gen Woo Audio WA6 doing tube duty. My current tubes are a Sophia Electric Aqua 274B Rectifier and a couple of GE 6DR7 Black Plates and the S2's just sing. Beautifully. They are exquisite. At $600 they are quite spendy but open-box will set you back $400 or so, that's what I paid. If you're a fan of the Sennheiser line the S2 might be right up your ally. It's a different sounding headphone to be sure but that's not a bad thing, Not at all!

[@MasterMarslander]

What a great story! Thank you for sharing!

[@crazyredwood1488]

Really enjoyable review. I really like your "compare" videos. It's cool to have an already reviewed headphone to have a baseline for the new product.

[@chungang7037]

great and fair review!

[@doskungen]

This is the best review of these headphones I've seen. I have and love the HD600/650 (before the design reboot) and got the HD660S2 just a few days ago. They are AMAZING headphones and they sound SO good. One thing I wonder about though if you can confirm this is if Sennheiser changed something about the earpads from the older models to this one because it feels much firmer to me. Could be because they are new of course, but yeah ... the the old pads feel much softer to me. Maybe they made them thicker/firmer for the sake of the sound signature?

[@MasterMarslander]

Very kind of you! I have a newish HD600 that I've played with when testing the HD660S2. The pads are very similar in firmness. The more you use them, naturally the softer the pads become. So I think it's just a wear in period you need.

[@the12gaugeshotty]

I just got the HD660S2 as well. An upgrade from my HD58X by a mile. Absolutely loving these and they have dropped to $399 on Amazon currently. I read that the change in the pads was to make them last longer? I guess time will tell with these. They split time with the Apos Caspians that I got a couple months ago.

[@markymark6229]

How do you like the S2 vs the 600 and 650?

[@MasterMarslander]

@@markymark6229 600 = the default magical Sen sound. 650 adds a little punch to that sound. 660S2 matures the sound and adds more focus. I do plan on making a comparison video for all the 600 series Sens in the near future.

[@ChillToMusic87]

A year or two ago, Sennheiser changed manufacturer/supplier for their earpads. Compared to the pads that they used to use the new ones are are firmer and a bit deeper and also have a clear film layer on the back of the pad. I have both types of pads so I know for sure the differences. I prefer the current pads.

[@user-bz5cf8ne7q]

I haven't purchased a Sennheiser headphone since the 560 Ovation II. I waited for the price to come down on the S2 and got it for $400. I am really enjoying the sound.

[@MasterMarslander]

That is the perfect price point for the S2. Congrats, and I'm glad you're enjoying it!

[@baltzy6458]

Using these on a fiio k5 pro. Seems to run them fine, by far the best headphones I have used.

[@spektrograf]

Just a point of clarification that the 660S2 drivers are NOT the same as the older HD580/600's or HD650's. They're current gen drivers that have been voiced to sound /similar/ to those older headphones. Eric Palonen from Sennheiser addresses this directly on post #85 "Dive deeper into legendary sound. Let’s meet the HD 660S2" on Head-fi. Otherwise, great view-thorough and thoughtful. Love it!

[@artureff3046]

HD660s/660s2 have HD700 driver

[@Tripokaridos22]

Great Review i have all HD5 and HD 6 line and u are very correct, But i have to say that Drivers on HD660S2 are smaller than 600 and 650 yeah they have the red coil but is also shorter and honestly it has more common with 660s driver , on 660s blue coil is also 38m also short and also use the same air metal filter behind , also even that 660s2 are 300ohm in reality they drive power is closer to 660s than 600, 600 need way more power than 660s2. About sound ? HD600 the most neutral and vocal friendly, 650 the smoothest, 6xx the darkest mid bass , 660s the fastest best imaging and soundstage , and 660s2 are warm but not warm like 650 or 6xx that the warm is from mid bass , 660s2 are warmer compared to 660s or because of mid treble , also 660s2 have the most low bass and 6XX the most High bass .

[@6643bear]

Hi thanks good r for your reply on this headphones, I just bought an open box 660s2 for only £269, and it sounds pretty good and similar to my 6xx with the custom cans bass mod in the lower bass area , regards again mark

[@MasterMarslander]

@6643bear Thanks Mark!

[@meh-hair-Vaughn]

You mentioned in the video that these shine on tube amplifiers. In particular, which tube amp would you recommend with these? Thanks for the video!

[@MasterMarslander]

I ran them on an xDuoo TA-26s. Beautiful.

[@mikeg2491]

Seems sound awesome on a Darkvoice. I’d also recommend vintage solid state amps

[@martyn_g]

These certainly image better and sound clearer to my ears then the HD650. Also with certain tracks, the 650 could sound shouty in the mids, whereas the 660S2 didn’t. Now before everyone jumps on me and talks about amping, it was on a rig that compromised a Bryston DAC into a WA23 Luna.

[@TheVeganVicar]

Thanks for informing your viewers from where you spotted the discounted price.

[@MuzdokOfficial]

Well explained detailed impressions of sound quality in your reviews. So are these your favorites now in the HD600 series?

[@MuzdokOfficial]

I think you said still your Drop HD6XX nm😆

[@MasterMarslander]

@@MuzdokOfficial Yeah man, it's hard. HD600 and HD6XX are so freaking good that anything else in the 600 series just feel kind of meh.

[@MuzdokOfficial]

@@MasterMarslander 😎

[@shashi6745]

Can you please recommend a budget tube amp to pair with HD660S2

[@MasterMarslander]

I use an Xduoo TA26s. Very good desktop tube amp. amzn.to/3TfNiPR

[@6643bear]

Hi, great and interesting video, I recently bought the 660 s as had very good deal of £259 as the s2 came out, I tend to use mine with my ifi zen v2 dac, with the true bass button selected which makes the bass alive , but I have done recently the custom cans mod for the 6xx, and does improve the lower end of the bass, I see that s2 doesn't come in the nice hinged box and now that the cables are now 1.8m -6ft cable as in the 660 S has the 10ft cable . I did notice that the ear pads on the s2 looks thicker than s1 and my 6xx which are 3/4” 20mm. As well as the 660s It’s like my old hd575 has 1” thickness pads . Regards mark

[@MasterMarslander]

Thanks for sharing Mark! Yes, I believe they changed the pads recently, so there is a difference in thickness and depth.

[@6643bear]

@@MasterMarslander thanks for your reply , I bet they are more comfortable than the 6xx and my 660 s, I like to get hold of 2 sets of those at some point. Thanks mark

[@MasterMarslander]

@@6643bear It's hard to say which is more comfortable, as my HD6XX is so well broken in. Out of the box though, as memory serves, I do think the HD660S2 is less aggressive with the clamp force, which would be a result of the new pad design. Both on my head right now are wonderfully comfortable.

[@6643bear]

@@MasterMarslander hi, very interesting., my 6xx with the custom cans bass mod I tend to use a lot over my 660s , but my most comfortable is 575s , i only started using these on my other system. Kind regards mark

[@CardinalsFanever]

iBasso SR3 review, please 😀 and AKG K361/371 😉

[@patricaomas8750]

Living in Ireland this model is selling for 450 refurbished from Sennheiser what would your thoughts be about that and your experience with Fiio K9 ESS do you have?

[@MasterMarslander]

Right now the HD660S2 is on sale for the holidays for $399 new in the US, so I'd maybe see if you can find a similar deal before jumping on a refurbished set. If you don't see anything better though, $450 isn't a bad price at all. I don't have any experience with the Fiio K9 ESS at the moment. Looks like a pretty compelling amp though, albeit a little pricey.

[@patricaomas8750]

@@MasterMarslander

[@glennr1399]

Amazing review watched it on my drive home, I currently have astro a50s, I would love to hear what these are like for gaming and how much sound is outside the cups if that makes sense? It'd be my first set of open air headphones

[@MasterMarslander]

Incredibly immersion for gaming. Played Lethal Company over the weekend and it was insane.

[@glennr1399]

@@MasterMarslander thanks for the fast reply 🙌 have you still got them by any chance? I'd love a quick video even on Instagram or twitter to show the the outside sound because I'll be gaming at night time in the next room to the kids. ❤️

[@MasterMarslander]

@@glennr1399 They're a very open back design, so there will be quite a bit of sound leak. That being said, if you listen to them at a medium volume in a different room with the doors closed I highly doubt they would be able to hear you.

[@glennr1399]

@@MasterMarslander thanks again currently looking for some reviews with sound leak haha

[@Optropicraft]

@@glennr1399 Hey man I'm in your exact situation rn with A50s and wanting to upgrade to an open back set. did you end up switching to these and if you did how would you say they compare to to the a50s?

[@robinkleinsteuber5217]

"Toy" build or not, my HD6xx headphone is a wonderful joy to listen to and is one of my two mainstay headphones. Presently being driven by Nitsch x Schiit Magni Piety headphone amp. Seductive music reproduction personified! 😊👍🎶🎶

[@MasterMarslander]

You'll get no argument from me. Superb headphone.

[@droptables7663]

I'm curious, what is your opinion on these vs the T60 argons?

[@MasterMarslander]

Totally different. They are both great for different reasons, but Argons are always going to be something special.

[@soulfulfool]

@@MasterMarslander Argons really need a good amp, T60 can be sibilant if amp is too "clean"

[@sumanthduggirala1887]

between 600 and 6xx which do u prefer for vocals and which has better tuning, and do 600 have shouty vocals

[@MasterMarslander]

600 and 6XX are both fantastic. I don't find the 600 vocals to be shouty, I think they are vibrant and clear. I know some folks think otherwise. If the 600 is too sharp for you, plug it into a tube amp, or try the 6XX. 6XX are just a tad bit warmer.

[@sumanthduggirala1887]

@@MasterMarslander thanks, as your reviews are accurate, can u make a comparision between the two if possible, and can a dongle dac run these(just curious)

[@soulfulfool]

@@sumanthduggirala1887 I believe the only difference is dumping, customcans take them apart and showed it. 600 have better highs and cleaner mids, 6XX got better bass and overall warmer sound. Everything can be adjusted by amp pairing, dont think that they will perform at best with cheap amps

[@ChillToMusic87]

I own both but if I had to choose one, it would be the 6XX.

[@rauldon4596]

@@sumanthduggirala1887 the "shouty" vocals thing is quite a contradiction considering the HD600s r universally regarded as the "KING" of vocals. Nothing under $1000 (even higher i'd imagine) is going to reproduce vocals as naturally as the HD600.

[@DroidLocks6971]

Can I Use These With My Fiio BTR7

[@MasterMarslander]

BTR7 will probably be ok if you use the balanced port. Headphone comes with a 4.4 balanced cable, so you'll be set.

[@6643bear]

Hi again , the 660s2 is now available for £359, and temping at that price point , is it better than my 6xx with custom cans bass mod , I wonder. I had opportunity to get 660s2 open box and vip discount from a major hifi outlet in the Uk for only £269. They sound pretty good . Also the hd650 is now only £229 at he moment . Regards mark

[@MasterMarslander]

@6643bear that's a great price! As for how it compares to your 6XX, I can tell you that compared to the stock 6XX it has tighter and more refined bass, and a bit more focus. 6XX has a more natural timbre though overall.

[@6643bear]

@@MasterMarslander thanks for your reply, if the 660s2 sounds the same as my moded 6xx no point in getting the 669s2, I have 660s with much thicker pads they sound pretty good , I also have 560 too they sound good too, it’s interesting that my old hd575 had thicker pads compared all the Senn range is about 3/4” but pads I have fitted to my 6xx and 660s are 1.25” . Regards mark

[@ElChadNate]

Which out of the 3 do you recommend for gaming?

[@MasterMarslander]

Probable the 6XX. They all do great though.

[@ElChadNate]

@@MasterMarslander I love how the hd600 look not a huge fan of the color of the hd6xx given that in amazon the hd6xx is $270 I have a gift card there so I don't have much of an option to purchase somewhere else. Out of those two which do you still think is suitable for me?

[@MasterMarslander]

@elchadnatetv 600 has a more natural mid range. 6XX has a little more elevated bass range, which is nice for gaming. You could look for the 650 if you don't like the look of the 6XX. Very similar. Do make sure you have an amp for the headphones, though. Your PC or controller headphone jack won't cut it alone.

[@soulfulfool]

Deal breaker can be the fact that Hifiman dropped prices of everything. Lot of their gear are flawed by sharp highs and dry timbre but overall with new prices for example Ananda Stealth is for 350$ (refurb but with warranty) can represnt better deal. Considering the price difference me myself fan of dynamic drivers would pick up Ananda instead. If someone want a sennheiser headphones the easiest and most bang for the buck are 600/6XX, what doesnt change the fact that all of them need decent amp

[@ChrisStoneinator]

Depends if you plan on using them for more than a year. If you do, then you only need one pair of Sennys, whereas you'd need two pairs of Hifimans. That skews your value proposition a tad.

[@soulfulfool]

@@ChrisStoneinator my fav are dynamic driver headphones but not sennheiser xD they do too little for too much

[@jorgeluisfernandez2560]

Can i drive this with an dap like sony am2 or hiby r6 III? Thanks

[@MasterMarslander]

Both should do fine.

[@jorgeluisfernandez2560]

@@MasterMarslander thanks bro and between those daps which one you thinks is better? Thans

[@MasterMarslander]

@jorgeluisfernandez2560 oof, that's kind of tough. Few things are as nostalgic and cool as a Sony Walkman. I do think the Walkman is overpriced though. If I had to buy one of the two, I'd probably go with the Hiby.

[@DroidLocks6971]

Im Listening Via My Shokz OpenRun Pro

[@MasterMarslander]

Those are the ones with bone conduction, right? I've always wanted to try those. Super cool.

[@DroidLocks6971]

@MasterMarslander they are my daily pair I wear all day every day and the battery lasts 12 to 14 hours per charge

[@daywatch5354]

im new to this PC stuff please help, i bought a pair and they just got delivered. When i plug them in to my pc the audio is so low, its lower when i plug it into the front of the pc, im not sure how to tell if they are broken or if im just a tech idiot.

[@MasterMarslander]

So the HD 660S2 is a high impedance headphone, that means it really needs a dedicated headphone amplifier. The power output of your PC just doesn't offer enough umph. There are a lot of options out there, but if this is your first time with a setup like this and you want to make it simple, the Schiit Fulla is a decent place to start. amzn.to/47Us7Yp

[@daywatch5354]

@@MasterMarslander thanks thats helpful, and does the amp come with something that plugs into my pc or does the headphones come with it? i see 3 wires but not sure how it would plug into the pc if it’s plugged into the amp.

[@MasterMarslander]

@daywatch5354 the connection path goes PC to a DAC, to an AMP. Then your headphones goes into the amp. In this case, the Schiit Fulla is an amp/dav combo, so it would be PC to Fulla and plug the headphone into the fulla. I have a video on the channel for amp and dac basics that might be helpful to you.

[@JBizzle22]

Has anyone tried these yet for gaming? If so, please share your opinions!

[@MasterMarslander]

I've gamed with them plenty. Excellent precision. Just make sure you have an amp to drive them.

[@Tripokaridos22]

660s2 will go 350-400 easy in some time, Honestly in Europe they cost 400 in most stores at sale.

[@robertgosselin14]

Flagship ? Nope, not even close. HD600 & HD650 wipe the floor w/ the 660 S2

[@BlissCities]

Just a critique, stop rambling and get to the point, close to 30 mins for a headphones review this felt like a total drag. I hope you improve your videos in the future because I enjoy watching headphone reviews

[@MasterMarslander]

I appreciate the feedback. My intent is to be thorough. I always encourage the use of the video chapters to get to the subject most important to you.

[@megatherium100]

@@MasterMarslander Tbh I prefer this kind of long form format of reviews, if somebody is going to give his opinion on something, you sometimes have to give nuance and perspective to your views and conclusions, and so, you have to thorough, tho I understand this is not going to be for everyone.

[@Faine212]

@BlissCities I'm rather annoyed by your comment. Since you're being subjective not objective like you think you are and assuming he needs to improve something. I prefer review videos to be as detailed and opinionated as possible. Otherwise I'll feel like I'm missing information. if you dislike that then go find 20 second tiktok review videos or something, maybe that's more for you.

[@BlissCities]

@@Faine212 It is my opinion bro, opinions vary, I will watch and critique what is being posted for the mass audience on my own terms since I am the one to consume them. if you post it online expect to be critiqued weather you like it or not. if you are annoyed so easy I advise you to seek help.

[@Faine212]

@@BlissCities it was a figure of speech. I'm not annoyed as in I'm annoyed at you. However you were pointing something out as though it is objective without leaving any possibilities of you being biased. it's this kind of reviewing that I desire and to me that is subjectively superior to what you desire.

[@truongvuonghuy6760]

Can you suggest me some dac/amp models under $200 for this headphone? Thanks

[@MasterMarslander]

Any of the entry level Schiit models, such as the Magni/Modi would do you solid. Some of the Zen Can amps are on sale right now too - also solid options. If you want something a bit more portable I just did a review for the Hip Dac, which powers 600 series Sens very nicely.