[blochsidisco]

Just bought both the 660S and S2 directly from Sennheiser to compare the two, EUR200 and EUR335 respectively (b-stock). I also own and love the HD600s.
First impressions, the 660S sound like a bad 660S2 prototype. I can't quite believe how weird they sound. Vocals are terribly muffled and the rest of the frequency response just sounds off to me. I'm seriously wondering if I got a bad unit or something. Either way, they will be going back to Sennheiser.

The 660S2 on the other hand sound like a slightly less technically refined and sophisticated, more bassy HD600, but that's not necessarily a bad thing. I would characterise them as a cosy headphone, one for quiet evenings in the couch draped in your grandmother's blanket. While the HD600s demand a bit more of your attention. I never found the HD600s particularly fatiguing, but even less so with the S2s.

Not quite sure yet if the S2s are a worthy companion to my HD600s or redundant in my collection. They don't really do anything better than the HD600s, but because of their smooth and pleasant delivery I could actually see myself listening to them more. The S2s may also be a bit more versatile, as the HD600s can sound a bit too clinical and cluttered with some music, something the S2s don't seem to suffer from to the same extent.

 

[frkasper]

First impressions, the 660S sound like a bad 660S2 prototype. I can't quite believe how weird they sound. Vocals are terribly muffled and the rest of the frequency response just sounds off to me. I'm seriously wondering if I got a bad unit or something

Here is something no Youtuber will tell you: give it time and the veil will go away. Even for the HD660S.

If you do A/B straight away, of course S1 is more veiled and muffled than S2. But wait... The whole HD-6 line is veiled to begin with. Folks, in an era of instant gratification, we're the guinea pigs.

And before one starts casting stones, allow me to share you this:

But can't deny the S2 is the comfiest listening of all of them, after the ears adjust to the sound signature of the transducer. In short, tonally-wise to me:

• Instant gratification: HD-600
• Long-run: HD-660S2
• AC-DC: HD-650

Cheers.

 

[jonathan c]

• If you feel 660S2 (or other Senn 'six hundreds') are veiled, run it off a high impedance OTL h/p/a or off a high voltage delivery SS h/p/a. Then, replace the earside foams:

[fine mesh is used above]

 

[rafaelo]

AC-DC: HD-650

AC-DC: 58X

 

[blochsidisco]

Here is something no Youtuber will tell you: give it time and the veil will go away. Even for the HD660S.

If you do A/B straight away, of course S1 is more veiled and muffled than S2. But wait... The whole HD-6 line is veiled to begin with. Folks, in an era of instant gratification, we're the guinea pigs.

And before one starts casting stones, allow me to share you this:


But can't deny the S2 is the comfiest listening of all of them, after the ears adjust to the sound signature of the transducer. In short, tonally-wise to me:

• Instant gratification: HD-600
• Long-run: HD-660S2
• AC-DC: HD-650

Cheers.

I did spend a day with the 660s before trying the S2. Just sounded off from the first tune.

The S2 is certainly veiled but tastefully so. Feels very deliberate, like they tuned this headphone for the purpose of just enjoying music. Like turning down the brightness on your TV when you’re tired but still want to watch your favorite show.

 

[SennheiserTech]

This is an interesting turn in topic as the issue of "Sennheiser Veil" has been around for nearly as long as the 600 series and all the variants that have followed. I've owned my HD650's since 2002? Can't remember exactly, but early enough to be the black silk driver version and decades before coming to sennheiser to work. Compared to my point of reference at the time, a pair of AKG K240's they immediately struck me as a darker set of cans being a bit recessed in the mids and highs with a warmer bottom end. I will add that it didn't take long for me to find the AKG's as too bright and adopt the HD650 as my new point of reference (like about 15 minutes). Since then, I've come to own many headphones that I enjoy, but do strike me as being somewhat unnaturally bright. My Hi-Fi Man cans, as well as the BeyerDynamics, Grado SR325i are all good examples of headphones I regard highly that are still voiced a little bright for me when doing long term listening. Now, while I wouldn't hesitate to call the HD600 series of headphones "laid back" in the presentation, especially the HD650, I wouldn't call them veiled as there is rather good detail retrieval, especially with the HD660 versions, it just doesn't throw it in your face the way some headphones do. Listen to the HD800S and the details are vivid to the point where you could hear a gnat fart in the studio. No one who listens to them seems to disagree... in fact that or the soundstage are generally the first thing people note with them.

Here's the thing though, if I had to be on a desert island with one pair of Sennheiser headphones, it would either be the HD660s2 or HD490Pro (which I've been very much enjoying lately, but that's a different thread). I would say though that the HD490Pro does strike me as a bit of a bargain and has some very interesting options with the earpads. The HD800S, would not be on the list only because I get tired of listening to them. I end up losing site of the musical forest getting caught up in trying to hear every violin and harmonic overtone and subtlety of the recording environment reverb and so on. I don't end up not enjoying the music and the immersion in that analytic sound is impressive, however, it doesn't take many hours before I start to yearn for something that is not so detail intensive, but more in service of the music as a whole. I believe the wild success of all the HD600 family lies with the fact that they are simply musically correct for lack of a better way of putting it. That is not to say super flat or last word in detail, or best in bass or imaging. It is to say they that they do just about everything I mentioned well with a balance and perspective that offers a certain "rightness" to them that allows them to be used for hours at a time and longer with little or no fatigue. They're not euphonic as bad recordings will sound bad, but they do seem to bring out the best in most good recordings. What can I say, love 'em or maybe not so much, it can't be denied that the whole series does deserve a legendary status in headphone culture.

 

[SennheiserTech]

I did spend a day with the 660s before trying the S2. Just sounded off from the first tune.

The S2 is certainly veiled but tastefully so. Feels very deliberate, like they tuned this headphone for the purpose of just enjoying music. Like turning down the brightness on your TV when you’re tired but still want to watch your favorite show.

Just curious, do your 660S have a little "R" and "L" molded just above the earcups? If so, you've got the original 660S which had some issues sound wise. Sennheiser quickly revised the driver and baffling to correct the frequency response and get rid of some of the nasty top end grain that people tended to complain about.

 

[kman1211]

Just curious, do your 660S have a little "R" and "L" molded just above the earcups? If so, you've got the original 660S which had some issues sound wise. Sennheiser quickly revised the driver and baffling to correct the frequency response and get rid of some of the nasty top end grain that people tended to complain about.

I was wondering why the early HD 660S’s fatigued me so much and it was quite rough up top. Because later ones I don’t really have any major complaints about. I think the earliest ones also have the perforated sennheiser logo on the grills where it’s solid on the later pairs. Then the late production pairs have the new more angular molds and the refreshed pads.

 

[SHAMuuu]

I was wondering why the early HD 660S’s fatigued me so much and it was quite rough up top. Because later ones I don’t really have any major complaints about. I think the earliest ones also have the perforated sennheiser logo on the grills where it’s solid on the later pairs. Then the late production pairs have the new more angular molds and the refreshed pads.

This whole 660S story is becoming comical.

I only say this because only the ones with the "Sennheiser eye" will be in the know.

I feel for those who end up getting a "bargain" on those 660S with perforated logo and indented L & R logos thinking they will be in audio heaven, only to receive them and be showered with a toxic level of grain.

Also cannot help but wonder in 20 years, if these "RARE" first gen 660S will command a premium. Or perhaps they will be hated then as well.

 

[kman1211]

This whole 660S story is becoming comical.

I only say this because only the ones with the "Sennheiser eye" will be in the know.

I feel for those who end up getting a "bargain" on those 660S with perforated logo and indented L & R logos thinking they will be in audio heaven, only to receive them and be showered with a toxic level of grain.

Also cannot help but wonder in 20 years, if these "RARE" first gen 660S will command a premium. Or perhaps they will be hated then as well.

Yeah it is, definitely confirms there was a notable revision of them because my first HD 660S and current one sound nothing alike, at least it’s now basically confirmed they had a major revision early on. Definitely partially explains the wildly variable impressions of the headphone.

Of the entire HD 6xx line I’ve tried, I think the current revision of the HD 650 has the least amount of grain. The HD 660S2 definitely has less than the HD 660S including late production pairs but I think the HD 650 has the least overall.

 

[SHAMuuu]

Yeah it is, definitely confirms there was a notable revision of them because my first HD 660S and current one sound nothing alike, at least it’s now basically confirmed they had a major revision early on. Definitely partially explains the wildly variable impressions of the headphone.

Of the entire HD 6xx line I’ve tried, I think the current revision of the HD 650 has the least amount of grain. The HD 660S2 definitely has less than the HD 660S including late production pairs but I think the HD 650 has the least overall.

Would you take the S2 or the new HD650?

 

[kman1211]

Would you take the S2 or the new HD650?

Earlier I would say the S2, but after owning both for a while the HD 650 won out for me.

 

[nierika]

When I bought the 660S2s, I had a 6XX with really worn pads and there are so many out there, it didnt seem like it was worth it to sell it, so I picked up some non-OEM velour pads (very similar) and replaced my SE cable with a ddHiFi BC150XLR balanced 4pin XLR cable. I can't tell you what percentage of the change can be attributed to SE->BAL vs the wire materials and construction, but the sound changed drasticly. Though the highs are still a little recessed, there seems to be so much detail and the impression of a "veil" is mostly gone.

The 660S2s with stock 4.4mm also seemed to be slightly veiled, so based on my experience adding a Zu Mobius cable to a previous pair of 650s, I looked for a suggestion for silver-plated copper in this thread and ended up with the LQI Esprit cable. Pretty happy with the results. As mentioned previously, it's like the ultimate all-arounder and as a bonus, seems easier to drive off a portable DAC dongle. The 6XXs have more forward vocals and are missing the deepest bass, but are still fun to reach for with certain types of music. It's fun to have different flavors.

 

[SennheiserTech]

When I bought the 660S2s, I had a 6XX with really worn pads and there are so many out there, it didnt seem like it was worth it to sell it, so I picked up some non-OEM velour pads (very similar) and replaced my SE cable with a ddHiFi BC150XLR balanced 4pin XLR cable. I can't tell you what percentage of the change can be attributed to SE->BAL vs the wire materials and construction, but the sound changed drasticly. Though the highs are still a little recessed, there seems to be so much detail and the impression of a "veil" is mostly gone.

The 660S2s with stock 4.4mm also seemed to be slightly veiled, so based on my experience adding a Zu Mobius cable to a previous pair of 650s, I looked for a suggestion for silver-plated copper in this thread and ended up with the LQI Esprit cable. Pretty happy with the results. As mentioned previously, it's like the ultimate all-arounder and as a bonus, seems easier to drive off a portable DAC dongle. The 6XXs have more forward vocals and are missing the deepest bass, but are still fun to reach for with certain types of music. It's fun to have different flavors.

Variety is the spice of life, they all have their own personality!

 

[blochsidisco]

Just curious, do your 660S have a little "R" and "L" molded just above the earcups? If so, you've got the original 660S which had some issues sound wise. Sennheiser quickly revised the driver and baffling to correct the frequency response and get rid of some of the nasty top end grain that people tended to complain about.

Nope, just the “660S” above the earcups (assuming you mean the outward part of the headband)
Also it wasn’t top end grain that bothered me as much as the extremely muffled mids.
Anyhow, I have made my peace with the 660S not being for me but am quite intrigued by the S2’s potential