sound 7:18

I have been using iFi Zen DAC v1. balanced connection with HD660s and I love the experience. Very 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. They are not heavy, I can listen for a few hours without feeling fatigue. I mainly listen to classical music which I think HD660s is excellent for this genre. No matter it’s Chopin’s nocturne (solo piano) or Schubert’s string quartets or symphonies from 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

The 660S are great, and have replaced my 600. I hated the 650, the bass was loose and pissed on everything. The 660S strikes a perfect balance between the 600 and 650. It's just plain wonderful. Played on THX 789 and Qutest.

You do excellent reviews bro...right up there with other popular KZfaqrs! Cheers.

Hmmm interesting. I prefer the hd660s to the rest of the hd600 line by some margin. To me on my gear the hd660s is more detailed and faster than the others. It has fluid natural timbre that is addictive. The others were great too but the hd660s was to me a big improvement, in nearly every category. I'm still keeping my hd600 line of headphones for nostalgia, but clearly the hd660s is like 3 steps ahead of the rest.

HD 600 released in new version ! It would be very helpful to know if there are any changes in the build quality but mainly to the audio behavior of the new version compared to the older one. Thank you !!!

The part with the vocals was so well explained. Exactly what I was looking for.

Thanks for your review. You are the first one to dislike the 660S, that I have seen, out of about five reviewers. I am considering the 660S as my first introduction into the high resolution world.

Thanks for posting. This kind of subjective review is genuinely helpful. In this case, when I upgrade from my 600s it will not be to the 660S.

Also the 660s/58x sounds brighter, cleaner, more resolving than the 600, 650, 6xx. The 6xx scales better than all the others but you can get better sound from 660s, 58x with a lesser amp. All still require a decent amp to sound the best. I liked your review, i just have slightly different view on the sound, i agree on some points. I also am using different amps/dacs. Nice review!

The way he's describing these two headphones, I get the feeling he just didn't do volume matching to compensate for the different impedances, lol. He describes everything on the 660s as being "lower", which doesn't make any sense given all the other reviews and FR graphs out there.

Listen for yourself. Different people tell different stories. 600 are "baseline neutral" , no doubt about that. They make mids (such as voices) stand out. But some people feel they are too warm. Not really, IMO. Some people think the 650 are too bright (I don't think so at all) and the 660s even brighter. You must listen and decide for yourself, this is so subjective. People adapt to different sounds and judge others using their accustomed audio. Some people think 650 makes voice recessed. Others don't. If everything requires an A/B test this tells you how close they are. However if you want the defacto benchmark for neutrality I would go for 600. If I wanted more snap and sparkle, I would go 660s. My sweet spot is 650. Yours may not be, so check beforehand. We are truly spoiled for choice. ;-)

Hi , that’s very interesting comments you made, I have been looking at the 660s2 but I am hoping that a reviewer do a 6xx/ 650 with custom cans bass mod v the 660s2 to see if they are similar, I recommend getting customs cans mod to your 650 as does improve the bass at bottom end, I also have have 560 , old 575 as well, I tend to use my 660s straight on my ifi zen v2 dac with true bass button selected and does come alive my 6xx then 660s both of them has thicker ear pads , then my 560, on my rotel a11 cd11 t11 set up and use my 575 on my old Cambridge audio sonata system . I do like the sundaes too , regards mark

Ohms are not exactly the term the power you need. You might have AKG K701 that has 50 ohm, but you need a amp that deliver 1 or 2 watts power to drive it well.

What? No banana boxes?? Imposter! Lol

Great informative points yoy made , I fitted custom cans bass mod, I do recommend the mod as do improve the bass at bottom end, am hoping someone do a review hd650/6xx with bass mod against the 660s2 to see if they are similar, that why I haven’t bought the s2 as yet , I also have Hd 560 and old hd575, I use 575 on my other old Cambridge audio sonata system , by the way I also fitted thicker pads in my 6xx and 660s, it’s also interesting that my old 575 has thicker pads from new . At the moment it’s 6xx, then 660s then 560s, I like also the sundara and my get one later . Oh yes my 660s was made in Romania too . Regards mark

I purchased the HD 660s a couple of years ago and really was disappointed from their sound signature / sound quality, they sound like the music is being played through a thick pillow, like not very clear at all, these were supposed to be my endgame headphone because all of the specs checked all the boxes for me, with their frequency response going as high as 40Khz, they are classified as high res headphones but to me they just sound too muffled.

I have bought 660s but I don't like the sound . I will change it for a HD600 .

Subscribed. Nice vid nice darth vader voice man

Disagree completely with your review owning the 660S (and also the 58X) I think they are very wonderful micro detailed headphones in bass, mids and treble. Definitely think there is something wrong with that unit as I definitely notice a night and day difference between these and the 58X Jubilees. 660S is a much superior headphone. I'm not saying they are perfect, but you know there's something wrong with your unit when almost every other reviewer or owner have been praising the 660S.

Interesting. Not sure what dac you are using though. I was using Fostex HP-A4BL and the 660S for me compared to the 650 had a lot more treble and sounded very aggressive (0 chill). The 660S were more similar to DT990 250ohm that I used to have and I compared them one next to another. I returned the 660S and now I have HD 650 which I prefer over any other headphone I had till now, HE 4XX had nice bass though and soundstage but QC for them was horrible (got 2 defective units) and the latter one had more treble than the first pair I got and quite a bit more of it. I am treble sensitive and young so my hearing is pretty good. I listen to many genres from classical to electronic and everything in between. 660S for me sounded like DT990 but with a bit less treble and a lot less bass (sub bass especially), the sound signature and detail was almost exactly the same which was surprising to me. Now with HD 650 and I'm planning on buying the Aune X1S again (I returned the first one that I got because I was just testing it). 650 are somewhat chill they are right in the middle I would say, songs that are aggressive will sound aggressive and songs that are chill will sound chill, so these are great for all genres. Didn't get the chance to test out HD 600 and I have no intention of buying them since I have 650 and loving them, I did test pretty much all the AT headphones (open backs and A2000Z, as well as MSR7) and I didn't like even one of them (sound signature was too chill and the bass was just nowhere to be found, with A2000Z being closest to my liking (it was close to 650 in terms of being able to be chill and aggressive) but the pads on AT headphones are way too thin so basically it's an on ear and not over ear, even though HD 650 touch my ears they don't sit on my ears like AT headphones did, the A2000Z was the most comfortable of the AT line as well as R70X. Wouldn't mind having R70X or AD1000X when I don't want treble to bother me though. Also if you get Sennheiser 600 line there is no upgrade just sidegrades, the same could be said if you get AD1000X, R70X or some nice planars.

I don't listen to that much vocal music, so I don't consider the 600 are for that. Acoustic music sounds the best on then though.

This is honestly interesting, perhaps Sennheiser had some bad batches with the HD660s? I owned the HD660s before and to me they were too bright compared to my HD650. Bought a HD58X for "fun" listening on mobile/ps4 and they are noticeably more relaxed/bassy in a good way than the HD660s were, and for the price it was really a nobrainer. I think you should try with another pair, this demands more investigation!

Thanks for talking me out of grabbing the 660s on a whim because of a descent boxing day sale from $639 AUD to $499 AUD. The HD600 are tempting at $495 from $599, however, I believe they have jumped by a hundred dollars in the past couple of years, I could be wrong though. I've seen them at $500 plenty, so it doesn't feel like a bargain, though no doubt it is in terms of bang for buck. God damn x-mass and GAS is toxic capitalist bullshit. I already have HD800s and LCD 2 Rev 2 running through an OG Burson Conductor, Matrix M-Stage, or Focusrite Clarett, and other instrument outputs. Plus a pair of 1964 EARS V6 C-IEMS that still rock after a good 10 years, and a fairly recently aquired and seldom used pair of Philips Fidelio X2(?) as a DAP friendly beater set of cans for travel and hard use scenarios. Now this sale is making me rationalise getting the HD600 to sit above the Phillips, as they are such an iconic and great sounding set of cans with easy and cheap user replaceable parts. Fuck me. I really don't need more cans. The world is going to shit, and the cost of living makes food and gas feel like a luxury if consumed above the bare minimum needed for survival. Although I have a lot of cool gadgets, it's not because I'm wealthy, it's because I'm irresponsible with money. By western standards, I'm well in the depths of relative poverty. I feel guilty, and stupid looking around my room at the money I can see that I've wasted throughout my life in the form of tangible goods. And that is just what I can see in my current vicinity. I've been frugal for a long time only paying for necessities in all other areas of life, so I can afford nice audio gear and instruments. Times are getting tougher for everybody right now to the point that survival is becoming a luxury many people cannot afford. And here I am, wasting, or preparing to waste the little cash I have as a buffer between being broke and destitute on the things that make the though of continued survival tolerable. The world is fucked, and I cannot shirk away all responsibility for it being that way. I'm part of the problem, just like everyone else, within degrees, of course. If anything I need, besides more drugs, is consumable/wear items for the gear I have, a few cables to set my little studio up more effectively. A descent set of studio monitors should be the only thing worth dropping cash on, as I currently don't have any. Yet a damn sale made me lose my mind and start Gassing over a 5th set of cans that aren't even as good as my three best pairs. For an extra $300 AUD, I could get an open box pair of ADAM T8V, or new KRK G4 8's. Now they would be handy. But god damn, I'm going to have to sell some shit to justify blowing that sort of cash on something that won't even get me high. But out of all the shit that I need and do not have, monitors are the obvious choice. Of all the things I have that I don't need, I'm putting it all up for sale. Maybe enough of it sold quick enough, I could get the monitors, 600's, and stay high for a while longer. Fuck it. That's my plan. Sorry for off topic stream of consciousness. Though it helped me to come up with a plan of action and put the silly idea of getting HD 660s to bed. What's really fucked up, is that after playing instruments for so long, and also being injured which limits my ability to play like I used to (though I listen better than ever, despite a > mild case of tinnitus), I don't even get that much joy out of music anymore. But it is who I am; whatever that means. Edit: Goddamn HD650 on sale too, $800AUD to $600AUD. Fuck me, please. Literally. Sex work is starting to look appealing to me. Though I doubt I would make enough to buy a pair of Raycons.

this conparacion video sounds great in my hd 660s!!!

Great job

Great ta

I heard there is some differences between the 6xx and 650. Did you notice?

Hi great informative video, I bought 660s recently for £259 , because of the price point , I have 6xx with custom cabs bass mod and that become my go to headphones, I wonder if u get a chance to review 660s2 , regards mark

I find vocals on 660s a bit harsh, is this me ??? And are 600s smoother ??

it seems like people always prefer the old from the new in this line of headphones. I remember a lot of reviewers and people in forums preferring the 580 (not 58X) over the 600 and 650 before the 660s came out, because of the sound signature and not technical performance.

You left off the 58x mids. what do you have to say about them?

You guys have got to try the 660s with the balance cable included. I bought an adapter (3.5mm Male to Female 2.5mm/4.4mm Adapter Balanced Cable Cord for NW-WM1Z ZX300A) on ebay and I think the sound improved a lot. Not to mention, I burned them in for 24 hours. Try it and see if that works for you.

The only review I agree with after owning both HD600 and HD660x. More accurate than even Tyler at InnerFidelity or any of the amateurs with pretty videos and poor information. The only things I somewhat disagree with is the comment on HD660s bass is a bit harsh, I agree its not super detailed but the bass is really nice and present without being muddy in jazz/classical; also the comment that HD600 is narrow without soundstage I disagree with wherein I find with classical tracks it sounds wider than HD660s and feels more like you are in the concert hall vs the HD660s where the orchestra is in your ear. I don’t think its fair to compare with HD58x, HD660s so far superior in quality but not necessarily value. HD58x is the best value entry level headphone ever made. I agree HD600 is superior to HD660s, but I have a friend with a terrific ear who would disagree!

this review doesn't agree with all reviews of 660s out there... do You think that Your 660s is faulty, because that doesn't make sense to me?

Somehow u have a very bad experience with the 660s. I got this a few days ago and first it had a very bad boxy sound, like as it would sound from underwater. Maybe u didnt warm it in, cuz from what u said i cant help but suspect that... Because after the warm in period (1-2 days) it sound quite different, just opened up. Its not that dark anymore, and the soundtage is better too. The graininess disappeared, and the highs dont have those little metallic effects anymore. (it was at first with some female vocals) So its quite interesting that opinions differs this much from this headphone. Oh and i use it with a fiio K7 and with balanced cable, maybe thats matters too. I have a HD600 too and honestly, now i like the 660s at least that much as the 600. They stronger and weaker in different spots, but no one is objectively better than the other, just different.

where do I find that blue color?

Look at the 660S FR and you will see, the "veil" is real (this time), since there aint no treble to speak of. I own a 660S and even though I got it brand new for 350€ I regret my purchase, since the 600 and 650 are way BETTER.

660s don’t care what you want to hear; they tell you what your gonna hear

For you which is better?

I'm in a position to upgrade.I'm toying with he idea of upgrading my 600s to a 800s.But I'm having a hard time with the cost.I am also toying with the idea of upgrading the cable of the 600.Im looking at the Cardas Parsec Headphone Cable, for a upgrade to the 600s.Any thoughts?

Did you even burn them in before reviewing? Used pads in equal shape for comparing each?

your opinion is exactly same as mine lol. i cannot understand why they made 660s. Also I feel hd800 is way better than hd800s. Anything comes with “s” from sennheiser seems to be darker than the original one.

The hd660s is the best of all sennheiser made in the last 20 years , i have tested all , the hd660s sounds perfect 33.33.33% bass.mids.highs , very very balanced sound , if he sound bad u have something wrong in your chain , or maybe u dont like professional balanced type of sound than doesn't emphasize any freq

Stopped watching when you said the default Aux Connector was a PLUS for the 600, over the TRS connection from 660S. We obviously don't do the same type of work or have same needs from the headphone....

Try the DT 990 600 ohm. It's incredible, and not just for the price. When you factor in the price I don't think it can be beat.

i was very conflicted between the two as im a very indecisive person this helped alot

Everyone has different hearing. Different preferences. The senn 6 series' sound can vary greatly depending on the source/amp/dac. I own 660s, 6xx, 600 and 58x jubilee. I dont own a 650 but it sounds identical to the 6xx. The 58x sounds similar to the 660s and I'd definitely consider the 58x to be a 6 series. Im my opinion the 660s is the superior headphone but not by alot over the others with the 600 being my least favorite. I'd buy the 58x, its a deal. Its 95% as good as the 660s and with a simple mod, good luck tellin them apart. 660s comes with better/more cables but the 58x value cant be beat and i prefer the sound over all the other 6 series aside from 660s. Mod the 58x, its a special headphone. Also its amazing for everything even gaming as its imaging is outstanding. You can pick up the location of sounds with such precision. Get the 58x, skip the rest.

Wow! This dude has no clue what he's talking about. Please don't listen to him and check both headphones before choosing the right one for you. DO NOT make your decision based on this review cause you will regret it. HD660s are brilliant headphones and definitely an improvement to HD600.

If you prefer the 600, then just say you prefer the 600. Don’t pretend that you can justify your preference with some “comparisons” that remotely make any sense. Obviously, many people have their nostalgia thing going on with the 600 so it’s understandable that you wanna trash the 660s or any other newer ones that are the successors to the 600.

Throw a Kimber Kable "AXIOS" cable on the HD600 and it's "One headphone to rule them all!" 🤣👌🎧✨🎼

Had both headphones. Can confirm this comparison makes no sense.

The 660 are not an upgrade from the 600. They are an alternate voicing. I prefer the Hd600.

The Hd600 is a reference.

An HD6xx powered with a tube amp with be heavenly

@7:20 gets to sound quality.

600 is better than 650 and 660s.

Hey man coming from the hyper x cloud would you recommend the 660s? I have a goxlr for my dac, is the change worth it or just negligible?

650’s all the way

Your hand doesn’t match with your voice

mute. then let us watch a comedy, actor: right hand.

stopped watching when i saw the crud under the nails.

But the 600 are ugly as hell 😄