Sennheiser HD 660S2 thread
Apr 1, 2023 at 4:48 AM Post #2,941 of 6,500
Vocal quality is better on the 6XX, but we probably already knew that, yeah? It's creamier, hazier, more velvety-smooth.
Tks for your reviews on the s2. May I ask if you can remove the foam disks behinds the drivers of the 6xx? To my ears it is like an unleashing from the haziness and mid-bass bloating on my 6xx. After removing the disks I don’t know if my LCD2 rev2 or my 6xx has more clear and devine mids
 
Apr 1, 2023 at 8:36 AM Post #2,943 of 6,500
Sennheiser HD660S2 arrived 1 hour ago... we will se how it compares on its own amp with the older brother..

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Apr 1, 2023 at 10:38 AM Post #2,945 of 6,500
After a few hours of listening, the 660S2 has retired my 6XX and 660S. The bass improvement over the 660S was clear to non-audiophile family members, even on a dongle, let alone on 300B tubes. It makes my HD6XX sound thin when volume matched by ear, and the HD6XX has new pads. The HD6XX details/resolution is a relic at this point.
It's pretty close to my Atrium, which has slightly better image separation/perceived details and more slam/impactful bass.
 
Apr 1, 2023 at 10:59 AM Post #2,946 of 6,500
I’m still fixated on comparing the S to the S2, haven’t yet plugged in any other cans to do A/B’s yet. I’m trying to answer the question, for myself, if the S2 is better than the original, and if I want to keep the S, S2 (or possibly both?)

I’m still an unabashed fan of the original 660S. Here are some more notes I’ve taken in the last 12 or so hours. Many of these differences amount to splitting hairs, and aren’t colossal differences by any stretch. I’m definitely beginning to see the appeal of the S2, and why it has so many proponents. But for me, I’m still a little bit leaning toward the OG side. I never thought that it really needed improvements, so any changes made to the S to make an S2 would have to be things that fall into the category of “I didn’t know I needed that!” I always thought that the S did so many things right, it is kind of perfect for what it is.

Resolution
I think the overall resolving power of the S2 is in fact a little better. Subtle details are highlighted that I can also hear on the S, but I hadn’t noticed on the first pass. I first hear them on the S2 and then go back and hunt for them on the S.

Bass
S bass is tighter, I can follow bass lines a little better, and I think the timbre of acoustic and electric bass guitars, as well as the lower range of acoustic guitars (nylon strings in particular) sounds better on the S. Bass depth sometimes sounds a little unnatural to me on S2, and distracts me often. Kick drums thump harder on the S2, and depending on the genre this could definitely be an improvement over S. I have a preference for clean mid-bass presentation, not usually a fan of a ~150 Hz hump (like 650). S2 has a little of this hump I think (also supported by graphs). S does not.

Treble
Definitely more sparkly on the S2. I like it more, but this (I think) is also the quality that’s making vocals sound a little distant and slightly more raspy/tizzy on the newer model. I think it’s giving the headphone a coolness, sonically speaking, that I think is less-good.

Vocal Quality
Vocal presentation has a touch more body on S, sounds more natural to me. S2 can sound a touch nasal wrt vocal quality, a little more zing. Some male vocals can sound a bit nasal sometimes, but it’s exaggerated on the S2, and sounds way more true-to-life on the S.

Imaging/Separation/Layering
S2 separation seems a touch better, imaging seems a smidge more precise. But there’s a slight bit of incoherence in the new model to my ears, like something’s off in the midrange. Again, it sounds “cooler” to me. Busy passages and poorer quality recordings seem to be handled better on the S2. They’re both pretty forgiving of crappy source material, but I think maybe the S2 is even more so. Good? Bad? You decide for yourself :)

Soundstage
Soundstage is definitely bigger (and TALLER) on the S2. It is less intimate (which could be a plus or a minus, depending). Depth of stage is improved on the S2, creating a more realistic perceived acoustic space. It’s more holographic to my ears. I think adding a touch of the HD800S’s spaciousness and detail was a goal of Sennheiser for this headphone, and it shows. I think it comes down to how much those traits mean to you in the spectrum of technicalities. For me, it’s not high on the list (soundstage width, I mean)

Dynamics
S2 is more dynamic. Snare hits are sometimes a little arresting in their immediacy. This is a huge plus for the S2, it’s more exciting.

I’m sure I’ll have more thoughts soon. And I’ll share them. In short, they’re pretty similar. Both are really solid headphones. I’m not convinced that the new flavor is better, just different. But I can definitely see why the newer model would appeal to others. I think the real bargain right now are all the 660S popping up in the classifieds for ~225 bucks. It’s like 98% the sound of the S2 for less than half the asking price.
Thanks for taking the time to give this detailed comparison. I found it vey helpful! 👍
 
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Apr 1, 2023 at 2:26 PM Post #2,948 of 6,500
This is gonna sound wild but i think I have found the holy grail: 660S2 driver in the 650 housing. Holy crap does it sound perfect. Got curious because I think there's a bit of naturalness missing from the stock 660S2. Removed the 660S2 driver completely from it's housing and slapped it in the 650 housing (it fits) and viola extreme naturalness with 660S2 speed and detail. And it looks the business. I don't really like the copper/black combo of 660S2:

DSC_0677.JPG

DSC_0678.JPG

DSC_0679.JPG

660S2 is empty now as the 650 driver does not fit in that housing.

Anybody w both headphones should experiment with this swap to see if it meets your preference. Nothing to lose haha
 
Apr 1, 2023 at 2:31 PM Post #2,949 of 6,500
This is gonna sound wild but i think I have found the holy grail: 660S2 driver in the 650 housing. Holy crap does it sound perfect. Got curious because I think there's a bit of naturalness missing from the stock 660S2. Removed the 660S2 driver completely from it's housing and slapped it in the 650 housing (it fits) and viola extreme naturalness with 660S2 speed and detail. And it looks the business. I don't really like the copper/black combo of 660S2:







660S2 is empty now as the 650 driver does not fit in that housing.

Anybody w both headphones should experiment with this swap to see if it meets your preference. Nothing to lose haha

Yes. that is wild as both housings are very similar, can you see what the difference is(if any)?
 
Apr 1, 2023 at 2:47 PM Post #2,950 of 6,500
This is gonna sound wild but i think I have found the holy grail: 660S2 driver in the 650 housing. Holy crap does it sound perfect. Got curious because I think there's a bit of naturalness missing from the stock 660S2. Removed the 660S2 driver completely from it's housing and slapped it in the 650 housing (it fits) and viola extreme naturalness with 660S2 speed and detail. And it looks the business. I don't really like the copper/black combo of 660S2:

DSC_0677.JPG

DSC_0678.JPG

DSC_0679.JPG

660S2 is empty now as the 650 driver does not fit in that housing.

Anybody w both headphones should experiment with this swap to see if it meets your preference. Nothing to lose haha
Gotta say that that’s a bit tempting, especially as I have two 650s………!
 
Apr 1, 2023 at 3:32 PM Post #2,951 of 6,500
Yes. that is wild as both housings are very similar, can you see what the difference is(if any)?


I put the empty 660S2 shell in storage and now I will listen and smoke a cigar. When I go in I'll get the get the 660S2 shell and disassemble both and snap a few pics.
 
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Apr 1, 2023 at 3:35 PM Post #2,952 of 6,500
I guess it is the same as like painting the HD800S black to make people feel it has less treble. You like the HD650 more and now the driver of the 660S2 in the old housing sound better, ha! Sonical memory is very short, how long did it take you to switch the drivers? 5 seconds?
 
Apr 1, 2023 at 3:37 PM Post #2,953 of 6,500
This is gonna sound wild but i think I have found the holy grail: 660S2 driver in the 650 housing. Holy crap does it sound perfect. Got curious because I think there's a bit of naturalness missing from the stock 660S2. Removed the 660S2 driver completely from it's housing and slapped it in the 650 housing (it fits) and viola extreme naturalness with 660S2 speed and detail. And it looks the business. I don't really like the copper/black combo of 660S2:







660S2 is empty now as the 650 driver does not fit in that housing.

Anybody w both headphones should experiment with this swap to see if it meets your preference. Nothing to lose haha

You took the actual drivers out and swapped them???

Am I missing something here ? XD

You took the s2 driver and put it into the actual housing of the 650, and that fits, but not vice versa? Please clarify if possible :p

*** I see you somewhat clarified in upper post. Not sure if relevant, but 580 drivers (especially early) sound fantastic in the 660 shell, with newer cable and that custom cans donut if it's just left empty. As in the whole 580 capsule with added clamp and copper or nickle donut. I think it sounds better than stock 580, though sad to not see 580 classic grills YMMV
 
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Apr 1, 2023 at 3:38 PM Post #2,954 of 6,500
This is gonna sound wild but i think I have found the holy grail: 660S2 driver in the 650 housing. Holy crap does it sound perfect. Got curious because I think there's a bit of naturalness missing from the stock 660S2. Removed the 660S2 driver completely from it's housing and slapped it in the 650 housing (it fits) and viola extreme naturalness with 660S2 speed and detail. And it looks the business. I don't really like the copper/black combo of 660S2:

DSC_0677.JPG

DSC_0678.JPG

DSC_0679.JPG

660S2 is empty now as the 650 driver does not fit in that housing.

Anybody w both headphones should experiment with this swap to see if it meets your preference. Nothing to lose haha
I think the mesh is different on the HD 600/650 than the HD 660S/S2. I believe it was said the HD 660S/S2 uses a stainless steel mesh, whereas it's an acoustic silk on the HD 600/650.
 
Apr 1, 2023 at 3:39 PM Post #2,955 of 6,500
You took the actual drivers out and swapped them???

Am I missing something here ? XD

You took the s2 driver and put it into the actual housing of the 650, and that fits, but not vice versa? Please clarify if possible :p
Yes notice the glossy housing on the HD 650 and the non glossy on the HD 660 S2. Only the HD 650 has that glossy plastic on the earcups.
 

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