Purpose 0:10 Build/Accessories 0:30 Comfort 2:17 Bass 4:32 Midrange 6:02 Treble 7:26 Soundstage 8:21 Isolation 8:54 Genre Pairing 9:32 Amp Needs 10:39 Important Takeaways 11:36 HD 600 is SOLD (12/18/2017) Sennheiser has confirmed the pads are slightly different and they will only be selling this new type of pad from now on.

I had my eyes on the 600 series for a long time, after i bought the 555 about 10 years ago. Now I could finally afford new bins and even though the 555 are still kicking and I like them a lot, there is a world of improvement between the two. The 660s totally squish my head but the pain is totally worth it :))

I am using iFi Zen DAC v1. balanced connection with HD660s. Very happy with the results. They are very detailed, smooth, natural and realistic sound with a touch of warmth. With 150 ohm impedance I never need to turn the volume above 11 o’clock. As it is not heavy, I can listen for a few hours without feeling fatigue. I mainly listen to classical music which I think HD660s is ideal for this genre. No matter it’s Chopin’s nocturne (solo piano) or Schubert’s string quartets or symphonies by Beethoven and Mahler involving 100 + pieces of instruments of varied tones and textures, the HD660s reproduces them with ease and accuracy. The HD660S makes me feel I am sitting right in the best seat of the concert hall.

A little late commenting here, but I totally agree with your assessment and comparison to the rest in the line. With the EQ flat, I thought that the extra dip in the upper mids of the 660s were detrimental to detail (like attack of guitar strings and crunch in metal), but when EQ'd to taste (slight smiley: +3db shelf at 90hz and 4.8k/1.00q, and -3db at 750hz/0.61q), the upper mids of the 600/650 get shouty and stand out. When flat, I like the neutrality of the 600/650 better, but when EQ'd to taste, I like the 660s the best. It's just more musical, faster, and punchier than the others, and the frequency response remains smooth throughout with EQ. The slightly more recessed upper mids actually favor the 660s in regards to a broader appeal to different music genres, and how they respond to EQ. I think if they were $300, they are a no-brainer. - [EDIT: but I do flip flop between preferring either 660s or 600/650. Not only are the recessed upper mids of the 660s it's more interesting difference that can be seen as positive, it's also it's most detrimental trait]

Great review, I am planning on making a review on this as well. Glad to hear you like them so much, there is a lot of hate for them which is sad because they really impressed me. I didnt like the HD 650 due to it sounding too laid back and coming across as slow, in contrast the 660 s is the fastest dynamic headphone I have heard thus far. This is to date the best headphone I have heard for rock/metal and its sub-genres. Iron Maidens Strange World and Phantom of the Opera are absolutely incredible on the 660 s. So far I have tried it with the Magni 3 Modi multibit combo as well with the Vivid version of the Burson Play. I can only speak for having tried on two different amps but it seems to have the 600 series trait of being greatly influenced by the amp. Compared to the rest of my headphones its sound seemed to change more. Will be interesting to hear how it scales once more people try it on other higher end gear. I have a theory that a lot of the negativity comes from people plugging into the same amps intended to make the 650 sound brighter/ more detailed which would probably not match well with the HD 660s as its already that out of the box. I would guess that things that sound good with the 600 would sound good with the 660s though as it seems closer to the 600 than the 650 to me.

Senhheiser HD 660S for me the best headphone , value for money is amazing also.

You have the exact same lamp as me dude. That's awesome. Lol also thanks for being the best headphone reviewer on KZfaq. Highly under rated!

Love the no beat around or vague review. Got what I wanted to hear. Thaxs

That's one of your best reviews yet

Best to listen to the 660s yourself & then make your own decision. I’m currently listening to the 660s & the 600 at home so I’m making my mind up this morning as to which pair to purchase

This was a great review. After 18 months, I would say that the 660S is a good headphone, but for me, it has not superseded the 600, for me the 600 is still Sennheiser’s finest headphone other than the Orpheus and He-1.

I have both the 660s and the 599...I got the 599 first because i wanted to upgrade my old 558's. I've never been willing to pay more than a certain amount for headphones even if could afford them so the 599's were gonna be it for me(almost bought the k712). I happened to find a pair of brand new 660s on ebay for $380 about 3 months later and didn't want to pass up the deal so i bought them. Initially i was disappointed because they seemed to sound no better than the 599. But after about 2 weeks I did an A/B comparison with both headphones on the same amp and it was clear that the 660s was "better". The sound seperation was the first thing i noticed, and the imaging was the next. Every song i played seemed to have more room for the individual instruments as well as a specific location for each. The 599's weren't bad but going back and forth, it became more obvious which headphone was better. Listening to one on Tuesday and then the other on Friday won't tell you much. So now, the 599's are what i use when I'm out and about while the 660s is what i use when im in my office for the majority of the day.

I would have bought them without hesitation if they improved marginally the bass/subbass extension, the only major thing that can annoy me on my beloved HD600

Don't sell the HD-600 metal571, it's the air-cooled Porsche 911 of the range! As the paint starts to fade on the newer "improved" models, you'll pine for that classic you once owned ;^)

I bought the HD 660s for a bargain £333 on Amazon. (Offer still on as of now!) I was also deciding between the HD 660s and the DT 1990 Pro's, but for £333 the HD 660s was a no brainer. I have a set of X2HR for great sound stage and more of a fun headphone. The HD 660s is more of a gaming headphone for me with the great imaging. Both are powered off a Fiio K5 Pro AMP/DAC. (Great headphones/AMP/DAC combo!!)

I use a 4db low-shelf at 80hz on mine, works very well.

This is the new headphone reviewer king ;)

Great review as always! I have an HD6XX now. I compared it directly to an HD600 and preferred the 6XX, although I should note that the pads on the 6XX were slightly more worn, whereas the 600 pads were close to like new... I didn't like the brightness and lack of bass of the HD600 with new pads. lol The 6XX had weightier low end and more body and evenness to the mids... I didn't try swapping the pads unfortunately. I did read that the HD6XX is slightly brighter than the HD650 though. lol Again, may be down to difference in pads... I wouldn't swap my 6XX for a 660S, but I do also have HE-400i, K553, Elear and CA Andromeda IEMs as well, so no need for more mid-fi headphones or any headphones for that matter. lol I think I might acquire a pair of Beyer DT250 250Ohm though as I really loved the sound of that headphone. You should get your hands on that one some time. It has this really natural timbre to it, especially in the mids and also lots of fine micro detail/nuance and really fast transients for a dynamic driver. I was really surprised how fast the DT250/250 is, especially considering how old this dynamic driver design is.

Senn needs to make a version of this with more bass extension. It will of course be a contender for Elex, but I don't think that would be a problem for Sennheiser.

ive been doing some a to b comparrisson with the 600 that i recently got and (2nd attempt) 660. I have stax l700 and srm 353x as my daily driver but im looking for something cheaper and portable. when i first put on the 600 i definitely had a few wow moments. for less than $300 these are easily better than $1,000 headphones. to an extent i may even like them over the 800s. i tried on the 660 and didnt really have any wow moments. yes the bass is just better but maybe its in the mids but i dont hear the same clarity i do with the 600. acoustic guitar, vocals they dont come through as clear for me. normally i like some good bass and soundstage but the bass is good enough on the 600 and the soundstage although not wide, surrounds my head very closely as if im sitting in the middle of the band and theyre spread around me in close vicinity. Short story long, not considering the cost, i think i prefer the 600 more

3 years later… Still Glad I followed this choice vs the others that r doing this KZfaq headphone review thing for a living. 👍

choosing headphone iss tooooo damnnnn hard all i i want is to listen to the beatles/pinkfloyd/tame impala/deep purple while i relax. and listen to electronic when i game. why it's so hard to choose? and don't get me started on the amp/dac choices great review, you seem to be overall pretty honest person

I could run them really well of my lgv30 amp by the way, obviously not the highest quality sound but the volume was decent. Mind you the 650's worked pretty well with that phone as well :)

Glad you hit hard on the importance of pads on this series, I just changed my 650 pads after 9 months thinking me having bent the headband to relieve clamp would decrease wear. NOPE, had my mind blown from how dark they sounded and how good they sound now with new pads. It's kinda ridiculous actually.

I have a set and they are truly amazing. I would say 99.99% of the population would need no greater headphones than the 660s.

4:10 Zeos voice cameo

The 660s are great, love them

Nice clear review ! One thing I do not understand: Why hasn't Sennheiser improved the soundstage? They are capable to do that, is it not? ..... So you're right, they are overpriced.

Really quality review. You're great on the mic

After getting them I was first disappointed. Too bright, clamp and pads different. But after a weak everything soften, even the trebble but very weak bass and no excitement at all. As they say "too analytic". I was ready to send them back when I tryed them balanced. Oh my God everything melted and finally they were alive. The emotion, the beat, the heart ! Something similar happend with my 598 and my 6xx. Sennheiser headphones should be run only balanced if you use a solid state amp. The difference is monumental !

Got these today at Sennheiser’s outlet store for €199, minus my 10% discount code. Paid €180. I feel like a thief. The only problem is that I don’t have an amp (yet) 😀

If I may add, as an owner of 660, one thing needs to be mentioned - they absolutely require good and powerfull amp/dac. I've had them for a year, tried listening them with no amp, with dragonfly, with Aune s6 and anything in-between (mojo and so on). And they sounded like shit. Total disappointment. Only when I went to listen to lcd 2c I considered as a replacement and luckily I took 660 for comparison, and the shop had the LCDs paired with moon amp dac and obviously I tried 660 with the same amp. And it was such a huge change. Night and day. As a result I skipped LCDs and bought the amp. So my owner's take is - if you can't afford something like burson conductor or similar (or moon 230 had that I got and totally recommend) I would look for other headphones as you can get better result with something much cheeper.

I bought the HD 660s last week, I absolutely love them🎶🎶🎶

Ahhhh! . . . just realised my main pastime is actually watching reviews of the products which are themselves just supposed to be for doing what is supposed to be the main pastime!

660S or DT 1990?

Hmm a fairly glowing review from you there. I've been looking for a second set of headphones to pair with my AKG K712...

Bro, will you be getting the Massdrop HD58x’s when they’re available? Can you please hassle Massdrop to send you a preproduction pair?

I bought mine in Berlin in early December at the Sennheiser store. I knew nothing about the 600 series and therefore went in blind. I tried a variety of different songs and genres on the 599, 650 and 660s. This was on their set up and amp and with my own lossless and 24bit music via the Fiio x5 3rd gen. The 660s was very drivable from the Fiio without an amp. However the headphones were for home use and the amp and that was the place for them. I found the 660s beautiful and bright. The 650 was darker. I appreciate I'm not the expert but the bright sound for the 660s was so welcoming I bought there and then for €450.

Hd 600 and 650 are still legendary. This one doesn't make the cut for legendary status.

Oh man I was hoping you would come back in the future. Its been 5 years...

You dont mention anything about imaging, in that aspect they are huge improvement over 600s imo. Also about being easy to drive or sensitivity, i think the specs are just correct but you dont notice it as much in perceived loudness because it leaks substantially more than 600s.

Hey metal. Hope you're doing well ever since you've retired from reviewing audiophile gear. Miss your reviews man. Take care!

Hi , I fitted thicker pads in my 660s sounds just a. It more basey . Regards mark

Will get a pair when they drop to ~350...

Great review! It seems like I won't be upgrading to 660S since I adore the sound signature of my 6XX. Btw, I just got my HD800 last week and my overall impressions are pretty good. They sounded fairly bright on my magni modi combo but after plugging them into my Darkvoice tube amp, The treble felt slightly relaxed. I also tried your EQ settings and surprisingly, they sounded very dark to my ears so I slightly adjusted the treble(-5db) and bass(+3db) which seriously made them very neutral to my ears. Now I have the perfect settings for my HD800. No need to risk doing the SDR mod now. And finally, their overall detail and soundstage is retarded lol.

I've got the M50X which is very bass forward. I bought these with the expectation of hearing more details and much less bass to contrast the M50X.

Would have been nice to see upgraded construction materials without altering enclosure size/shape. I love my 650's, but the build quality is meh for the price.

How is the vocals and mids on this compared to DT 1990 Pro?

You made me wanting to buy this headphones.

Interesting how different you guys review. For tyll it was a disappointment. For you and Josh for example it's a better hd 600. Found your channel and I will support you 🤘🏻

Hi... Maybe my ears are simply not good enough to hear all the details... Maybe it's a problem of volume matching... Maybe the DAC/AMP combo I'm using is not really Hi-Fi (JDS labs the element)... Who knows.... BUT: I could not hear much difference between those and the HD 598 I have for two years. Sometimes I had the sense (and again, this could be volume matching) that the HD 598 are clearer. I can't say that the 660 S is my best purchase... And I bought them for ~650 USD, because this is the price of those headphones here in Israel...

How much smaller is the soundstage on the 660s compared to the HD 598? I was looking to pick up some new cans for gaming/music primarily, but I'm not sure if 660s has a good enough soundstage for gaming.

Great review. You liked this headphone much more than Tyll did. It is what it is, We all like different things. I enjoy hearing the different opinions. We have a hi-fi store within 45 minutes from where I live, and they carry these headphones, so I will check them out. But I really have my eyes on the LCD-2 classic for just a hundred bucks more

Hmm... all the reviews for 660 are so nice. I wonder, why did I preferred 600 when was choosing between them in shop?! I’ve been comparing them like for hour or two!

That subliminal, smirkey smile you got going on man ... makes ME smile EVERY time. :) It's almost like: "Yea, I laugh at most of these headphones, but in a good way, and I'll describe them for you here today. I smile like this because I have a custom Stax tuned to my ear shape, with perfect eq designed by a doctor of audio measurement hearing test master extraordinaire, with basement sized horn subwoofer system set up in my perfectly tuned asymmetric audio room you can't see, with Focal Grande Utopia EM EVO as a reference setup backed by a ...." well, you get the picture.

I'm glad you got these, I was wondering how they sound. I was hoping that since these might be using the hd700 driver they would have a wider soundstage and better imaging, but alas, they do not :( it's ok plenty of others to get.

Im confused coz I saw tyll reviews on these and he didnt liked it....maybe because of the pads issue you mentioned?

I've been reading about these for couple of days now that I've read quite a few times of owners mentioning that compared to 600 and even 650, the treble on 660S rolls off sharply after 12k, whereas the other two keep going all the way up to 15-16k. And that it's grainy on 660S. Metal, have you noticed anything like that? What are your thoughts on it?

That was a nice second opinion to the somewhat depressing Tyll's one. Do you know if it's true that 650s are being discontinued? Keep up the good work!

If the Sennheisr HD660 was the same price as the hd600 which one would you buy? I listen mostly to female vocal, Dido, Katie Melua, Celine Dion, Kate bush, Christina Perri. Though listen to queen, Eagles & evanescence as well.

K712pro vs hd660s (i have both ) K712pro - 20% wider Better highs 30% Lighter clamp force ( 30% lighter) The need wayyyy more power , to sound loud the same like hd660s you need at least 30% more power Very nice orange color and design More details Better price they cost almost half of the hd660s ( 380euro vs 220 euro today price 10/2019) Hd660s Better subbass and bass like 10% better Better fit , better shape of the ear cups, they stay fixed Better cables ( higher quality ) Very lightweight and breathable

Hey Metal could you post your EQ settings in the description if you still have them? Thanks for the videos!

For a first good headphone for listening to vinly and digital which do you recommend (600,650,660S)?

1:44 2:22 3:16 3:31 3:39 4:15 5:43 6:13 7:12 7:51 9:31 9:53 14:57 15:56

I upgraded to these from my HD 598, treble sound just like my HD 598, mids slightly better, and a whole lot of bass. I would call them HD 598 with bass

I don't find too much treble at all... maybe my source is ultra smooth. These are great non-fatiguing and neutral headphones. I got mine from Amazon UK for a little too much...but hey... I wanted them

Love to hear your thoughts in details on tube amp pairing with dynamic heaphones.

It's funny your review of the HD599 was what made me decide on them around a year ago. For the price they've been fantastic. Curious to know if you would recommend the 660s for gaming, I'm more concerned with imaging rather than super expansive sound stage. Have also been considering the 1990's, any recommendation either way?

I'm actually watching this video on 660s through my tablet, with no additional amp. Volume is roughly at 75%. You can, in fact, make this too loud without additional amplification. Not sure what kind of power a phone had 4 years ago, though. I'm using a Galaxy Tab s7+. I have the Drop premium fennestrated sheepskin pads on them. I can't tell the difference in sound, but they are maximum comfort with these. The mids are still pristine! I paid $255 for them on ebay.

Sennheiser actually says the pads are slightly different - this is per an official Sennheiser post on Head-Fi in response to a question. The pads are interchangeable but they are not identical to the ones that come with the HD 650 and HD 600.

Go to Zs review, runs the 660s on different dacs and amps......that was a great review of 660s, never found a cheaper headphone that sounded better......

Damn sir, you do a good review. Thank you.

660S all the way better in gaming/music imo than others 6xx series i have tried like 600 and 650! Not sure for 58X....

Great review as always!

Best soundstage or sound imaging headphones? I want to listen to music but also ASMR haha

What would be a good option for EDM and Rock music at around $600? I went with iSine20, but I would still prefer over the ear style, unless iSine20 have a better sound.

Used like new 199 eur? What do you think?

What was the tube amp you used with Attticus and HD600? Did I space out and miss it or did you just not mention it?

curious if you've had a chance to test out the 660S2? I'm looking to upgrade from my hd599's as I've had them for a few years now, heard mixed reviews on the 660 S2's.

I would love a comparison between the m1060c open mod. And the hd660

I have a query to anyone familar with Sennheiser headphones. I have a pair of wireless hdr 180's and was wondering which wired sennheisers are comparable. (Sound quality & signature)

Hey man! Love your reviews since you are listening to the same genre of music as I do. One question though, which mic are you using? I am on the lookout for one, and yours sounds pretty damn good.

Hello, great review about these HD 660S, I have them too and the HD58X, and to my ears, these two sound pretty similar, I'd like to know your opinion about these two pair of headphones. It would be great if you do a review of the HD 58x or a comparison. And what you think about them. I watched a couple of reviews, from zeos and he thinks almost the same. What do you think!!!.. greetings from Peru.

Hello. Many reviewers have highlighted that this headphone lacks the warm sound produced by 650S and is not even nearby 650S. I am looking for a headphone with detailed sound buts and warm sound. I mostly listen to songs that include Rhythm guitar and 80's rock and ballads. Is this model really worth buying?

I just bought a hd660s a couple weeks ago and been seeing allot of praise for the dt1990. Especialy the bass is supposed to be very good. But is it much better quality wise than the 660s? I like to listen to rock music with female vocals like avril lavigne for example. Which one would be better for that task? Also i have sonarworks to have them both be completely flat. Which one do you think would be superior given they both have the same frequentie curve? Love your channel btw.

i have m50x + dragonfly black and just listen to electronic music . i want to know buy hd 600 , 650 or 660s is good for me ? hd 600 , 650 or 660s + apogee groove is a good combination ? thx

I was awaiting your thoughts on this, like others have mentioned, Tyll and aornic both have qualms about these cans but even I've thought surely there would eventually be something made by sennheiser in the same product line that wouldn't be so much like the 600's but close to the sound signatures. Billie Holiday's Crazy Calls Me is buttery smooth and in the center of your head with the 600's. perhaps you could A/B the song with the 660 S just compare the difference in presentation, would love to know what you think. Cheers.

I've got AKG K702 and I'm looking for another pair that are comfortable and sound better, but I can't seem to find anything better under 250£ and my pair was 120£. Any ideas? I think 599 would be more comfortable, but either the same or worse sound than k702. Hmm...

Interesting polarizing opinions from reviewers.. I hope my dealer has this soon for audition.

Hi. I want to get the beyerdynamic DT770 Pro 80 Ohm and i want to use it with a audio interface. I currently have the behringer uphoria um2 but i want to get a much better one. So my question is; How well will the headphone with a audio interface do? and do you recomend it? If so, what interface would be the best? I would be really happy for a good answer because im searching allot but didnt find any good answers so far. thx :)

High clamping force, pads go flat quickly - seems like cause and effect to me.

hello i like your reveiws. i have a pair of sennheiser hd540 from 1985. where would you put those compared to any of the current models? are they worth upgrading or should i just get new pads for them? they are glorious sounding so im not sure exactly which model would be a sidegrade or an upgrade.

Hey, What are the top 3 open back headphones under $500 for mixing pop music. Thank You.

Man i have several heahphones in a middle range and i have high ends like focal elear and beyerdinamic amiron home, im looking for another can, so i want to know which i would pick? Dt 1990 pro or these senn 660s? Please answer me, it will be a great help!

would these sound good with a high impedance amp? and will not get distorted? (since they are 150 ohm..) thanks.

I love your eq for the 650. Do you still have your 660s eq saved for reference?

Please help with the choice. I need headphones for listening to music and playing games. Detailed sound, positioning in games and convenience are important. Don't want the headphones had a microphone in HyperX, Razer, and for music they are bad. Think buy Sennheiser, in my store has HD559, HD 569, but there is no tests on Russian language . Advise headphones for such a price, roughly 100$. From HD 559 or HD 569, or another firm. Sorry for my English

Mine should be here tomorrow!

Thank you sir! You surely know about Cans. I owned an HD600 headphone for 16 years and now they are totally worn out, I also think they don´t sound like before. What would you recommend as an upgrade for getting a pleasing sound while being accurate for mixing? I know this sounds general, but an opinion from a guru like you would be great. Cheers I´m glad I discovered your channel

would my komplete audio 6 be able to drive these? if not , what is a good decent not too expensive amp?