Yeah I feel the same 660s2 and S1 technically are better than the others and S2 a bit more, But vocals on 600 always feel like they are in ther bubble it's like the headphone tells u what to listen, Also on 650 headphone colour's and warm the sound telling u what to listen. On 660s2 is like...

Agree they do sound natural , but neutral I will go with 600 and warm with 650.

Do u use EQ on both 650 660s when u compared them ? Without EQ I also think that 660s are more lively. My point of view to all HD6 line is that if u like this signature line u like all of them some more and some less ... I understand that 650 are the warmer or the 600 vocals are the best or the...

That's strange my 660s have the biggest soundstage of them all 600 650 580 58x and 66s2 not by a lot but no way smaller.

Fully agree both 660 have amazing imaging, even compared to my Sundara .

Be careful with that after marker cables , pins 90% of the times are thicker and taller than stock ones and the inner connection is destroyed when u take in and out a lot of times.

Yeah they are for sure larger than Momentum , they are close to HD5 series .. 598 for example they was a bit larger on width , years ago i tried to make HD6XX Angled like HD5 line , i destroyed HD599 plastics to put HD6 driver there , i use both pads i use some brainwavz pads , nothing worked ...

Nope , everything is exactly the shame , HD 650 must have the older Black ring pads that have thicker and Shorter walls, New pads have thinner and taller wall.

Earcups are Exactly the same on 58X,6XX,580,600,650,660s,660s2 i am 100% sure about that , i have them in front of me :) All Earpads and parts fit to each other. Maybe u are saying about the Hybrid Earpads ? Because ear pads i know that they had 3 different versions of them over the years ...

They do look alike, strange... i am not expert just want to find out the materials used for these headphones. My 660s and S2 Black Painted Lines are Waaay thiner than yours S2 . and Only on 600 + 650 are Thicker .... also strange ( maybe its random i dont know)

I am not expert also , i have place 2 questions on Sennheiser contact support the one is about the baffle and the other about the coil the red ones vs the blue one . i am waiting a mail reply, the first answer was from Sennheiser Official youtube telling me that old 600 650 use acoustic silk and...

I got reply from Sennheiser they have great contact support, 660s and S2 use Steel, old models use acoustic silk.

Does anyone know If 660S2 use steel mech acoustic baffle like 660S use ? Or its Acoustic Silk like HD 600 and 650 ?

Its not bad to dislike a Headphone , for example i dislike Koss portas that everyone love . The problem is trashing a good quality headphone because u dont like the sound signature ( not talking about u ) , Me for example i can see the Superiority of Beyers and i have a lot of respect for them...

Really strange , U find S2 more fatigue than S1 , and also S2 more fatigue than Beyer T1.3 ??? Is this Gen 3 way different than Gen 2 ? doesnt have that Beyer type sound of 6k-7k peak ? I think that at the end of the day the hearing of people is really different .