I went ahead and threw a set of ZMF perf Lambskin pads on my 660S and improved the overall sound signature to my satisfaction. As a result, Iâll keep these and pass on the 660S2. I might have gone ahead with the trade-up if they didnât slap that 600-dollar price tag on them.
Of course, I had the luxury of already having a 660S in hand, bought and paid for. If I were starting from scratch, I would give the 660S2 more consideration. That said, I still donât think I would pay 600 for 'em.
Sennheiser HD 660s2 versus Sennheiser HD 650, which is the better Sennheiser headphone for you?
I am really enjoying my new to me headphones.
On Friday I was underwhelmed as I went from two straight weeks of the OG Clearâs to a very different and less dynamic headphone. That coincided with my urge to drink some rum and coke and rock and roll. Not the best way to introduce the Senns into my collection. 
Yesterday was a great jazz day and today was about five hours of Steely Dan/Donald Fagen music.
These things are super light and comfortable. More than enough bass for my jazz and The Dan. They definitely add a different dimension to my collection and are growing on me. Loving them on my iFi with a bit of bass boost.
Itâs almost like youâre saying theyâre prepared to meet the challenge of the new frontier.
Well, it has been a full week with the HD660S2âs. I was pretty disappointed the first day (last Friday), but that was for a few different reasons. The first was that I was still adjusting away from two straight weeks of the OG Focal Clearâs, which are super dynamic. Secondly I was pouring some rum down and looking to rock with some of my favourite rock music. Not really the specialty of any Sennheiser, IMO.
Not really fair on both counts.
I started Saturday off with jazz and then ran with every genre of music and every amp that I have. The S2âs have a nice clear sound and do most sounds very well. I do find them a bit bass light, but they do nicely with bass boost from my iFi and sound good on my Schiit Valhalla 2. They remind me very much of my HD660Sâs that I sold about 15 months ago. I used to call those my palate cleansers. Liked them, but never loved them. I suspect these will be the same. I did regret selling them.
For jazz, these are great. Also great with pop and pop/rock. IMO, these would not work well with Hip-Hop or EDM, unless you used some EQ/bass boost.
Their super power seems to be neutrality. In my collection:
Grado GH2âs have amazing mids and above.
iBasso SR2âs have great bass and mids.
Focal Clearâs are truly W-shaped. Great bass, mids and treble.
HiFiman HE6se V2âs with the iFi Pro iCAN (bass boost and 3D enabled) are the Clears on steroids.
I donât find anything standing out with the HD660S2âs. Nice, complete sound. More might stand out in a month or two.
Should also mention that these are super easy to drive. I expected 300 Ohms to be tougher. I canât get any amp out of low gain and even then I am at 9:00-10:00. But I am a quiet listener.
So far, my only minor complaint is a little bass light, but I knew that going in.
Youâve hit the nail on the head here. I put down my Utopia for a week when I finally got my 660s2 in off loan. Didnât take me very long at all to figure out that I like them more than the 6XX. I think that they are probably the most âcompleteâ sounding of the 6x0 series Sennheiser has come out with.
Problem I have is that they arenât Utopia, lol. So now they are just sitting there with the other things Iâm not using.
I hear the 660S2 as more complete as well, which, to my hearing, isnât a difficult thing to do vs 600/650, but then again, I never fell into the âawesome scaling potential, godlike timbreâ camp in the first place and I donât want to start a battle. I do sit in the â660S(1) sucksâ camp though. I was also pleasantly surprised by how the HD800S came alive (at least compared to what Iâve heard so far) on the ZĂ€hl, but if it needs 10k in amplification to achieve that then Iâd rather pass on it lol.
Do the drivers have the same frame layout as the 600/650? I can change the drivers between the two headbands depending on what Iâm wanting. I have old 600/650 drivers and would probably rotate between all three every so often. Is this possible with the new ones?
I was way late to buy HD660S2 but still when I did buy them on Amazon they were $599. The day after they shipped the price dropped to $499 & the day I got them the price dropped to $399. I tried to return them, but every time I tried it said there was an error. I guess it had something to do with me having bought them with installment payments. That was probably close to a year ago.
My only gripe(s) with the HD660S2 is that they are squeaky with the slightest head movement, but thats only noticeable at low volume. The stock cables are crap quality for the price of $599 that I paid.
My usual listening environment is noisy unfortunately, as it requires a window AC unit, plus I need at least the ceiling fan on high to be comfortable, so all of my open back cans will lose to my DT150s for isolation. The HD660S2 is no exception. However I can say, for an openback, the HD660S2 isnât drastically behind on bass performance compared to my DT150, which isnât far behind the bass performance of my Eris headphones, if even at all. As a side note, I used to think my CD900ST had a lot of bass. Now they seem to have no bass at all.
(Edit) Checking the CD900ST on my NAD C165BEE, I donât know why I said they have no bass at all. They have bass. Itâs just not at Eris, DT150 or HD660S2 levels of subbass. Yes the 660 has some reach into the subbass. At the $399 price they are now, Iâm wondering why I would need or want to spend more than that on a headphone. I have the DT1990 also & pick the 660S2 over those. The DT1990 seem pretty narrow sounding vs the 660S2 IMO.