[Snowfield]

Hi there,

I purchased HD660S recently and they sound amazing. This is my second pair of "good" headphones after having bought HD598 8 years ago while I was still in secondary school, so I I'm getting my value out of these headphones for sure (and avoiding trial-and-error tax). Unsatisfied by the sound I was getting by connecting directly to a MacBook, I purchased Khadas Tone Board and JDS Atom amp. Doing so made the headphones sound a lot better than it used to. The bass is reduced but better controlled and overall sounds much smoother and pleasing.

Overall does all genres very well, except for genres like EDM and modern music that utilize sub-base heavily. My airpods pro have a better sub-base than this. :/
Absolutely terrible for FPS games such as Overwatch. Although the soundstage is precise, it is inaccurate in that it presents everything too close. Too many times I look backwards to an imminent threat, only to be fooled by a non-threat far away.
Instruments and female vocals are downright heavenly, and badly mastered music doesn't sound too horrible. Overall, I'm very satisfied.

Mine seems to be an old stock, as it was made in Ireland and has all the original design elements. Regarding the suspected sound change, Is there a way to check the manufacture date without disassembling the headphones? I have accidentally pushed in the diaphragm of HD598 in the past, and I don't want it to happen again. Judging by my ears, these do not sound bright at all (even thought they sounded very dark having been accustomed to HD598) nor grainy, but I wouldn't really know because I've only auditioned the other 6-series headphones and never owned them.

The most concerning problem is that there's a noticeable channel imbalance playing 6k pure tone (verified by wearing headphones the other way). The sound comes from about 20 degrees left, and I'm wondering if it's normal. The rtings graph does show some discrepancy at that frequency as well, but I have no idea how audible that difference is.

 

[Mike F]

I wonder if it's possible Sennheiser didn't change the drivers at all and merely changed the thickness of the pads. When I recently changed the pads of my 600's the treble was brighter, which sounded a lot better to me. The same could have been done to the 660's, but the reverse.

Here's a quote from a 2017 HD660S article: https://www.innerfidelity.com/content/sennheiser-hd-660-s-over-ear-open-headphones



Sometimes I see photos of the 660's where I can swear the pads are thicker than other 660's. Then there's the fact that you can only buy one size pad from Sennheiser, for the 6 series. There is no exclusive, thicker pad for the 660 anywhere.

The HD660S had the new pads from the beginning. All HD660S’s have had the same pads and they are now standard throughout the range of six series headphones and also all replacements.

 

[Mike F]

The most concerning problem is that there's a noticeable channel imbalance playing 6k pure tone (verified by wearing headphones the other way). The sound comes from about 20 degrees left, and I'm wondering if it's normal. The rtings graph does show some discrepancy at that frequency as well, but I have no idea how audible that difference is.

That’s very strange. The HD660S have matched drivers and although no matching will be perfect there certainly shouldn’t be any audible channel imbalance. More likely to be your source I would think......

 

[Snowfield]

More likely to be your source I would think......

Tried on different sources and they're the same. 6Khz pure tone doesn't originate from the center, it's located roughly at my left eyeball. When I flip the headphones, it's the right eye.
It's probably not something that is noticeable on normal listening, and by no means do I have perfectly symmetrical ears, but the difference is clearly audible.

One of the websites I used:
https://www.szynalski.com/tone-generator/

 

[Mike F]

Tried on different sources and they're the same. 6Khz pure tone doesn't originate from the center, it's located roughly at my left eyeball. When I flip the headphones, it's the right eye.
It's probably not something that is noticeable on normal listening, and by no means do I have perfectly symmetrical ears, but the difference is clearly audible.

One of the websites I used:
https://www.szynalski.com/tone-generator/

Have you tried it from a different sound card/computer?

 

[Snowfield]

Have you tried it from a different sound card/computer?

By different source, I mean completely different computers with no passageway in common, other than the stock headphones cable.
Same exact result when connected directly to MacBook and when connected to a desktop via an amp and a dac.

 

[Mike F]

By different source, I mean completely different computers with no passageway in common, other than the stock headphones cable.
Same exact result when connected directly to MacBook and when connected to a desktop via an amp and a dac.

I’m away from home at the moment so I can’t try it myself, but presumably you don’t get similar results with other headphones?

 

[Mike F]

Also, is it possible for you to reverse the polarity of the headphone signal. Reversing the headphones on your head eliminates a problem with your hearing, but doesn’t exclude the possibility that it’s still source related........

 

[Asspirin]

It's the tone generator. I tried it with various headphones and the tone was always a little left-leaning. Single test tones are a terrible way to test headphones, by the way. Enjoy your music.

 

[Mike F]

It's the tone generator. I tried it with various headphones and the tone was always a little left-leaning. Single test tones are a terrible way to test headphones, by the way. Enjoy your music.

Thanks @Asspirin, I presumed it must be the source and not the headphones..........

 

[pietcux]

It's the tone generator. I tried it with various headphones and the tone was always a little left-leaning. Single test tones are a terrible way to test headphones, by the way. Enjoy your music.

As far as I know the driver matching is made by comparing the spl @ 1000Hz. so if your pair has a mismatch @ 6000 Hz you still have matched drivers. only bad luck that you are sensitive in that region.

 

[Mike F]

As far as I know the driver matching is made by comparing the spl @ 1000Hz. so if your pair has a mismatch @ 6000 Hz you still have matched drivers. only bad luck that you are sensitive in that region.

@pietcux you're probably right about the driver matching being done at 1kHz. That would make sense as that's the most sensitive frequency for the human ear. However, it wasn't Asspirin who had the mismatch problem. I suggested to Snowfield that the problem was the source and that he could eliminate the HD660S as the problem by seeing if the problem persisted with several different pairs of headphones. Asspirin was just confirming that in fact it did.

 

[Asspirin]

After a couple of rounds of Hunt: Showdown, I can confirm that the HD660S is a potent gaming-headphone. Soundstage is rather average, as all 600-series headphones, but imaging is exceptionally precise and spot-on. I have yet to head a headphone with better imaging.

 

[mmq2404]

Finally got mine for 345$ with no warranty, the unit is 100% new unused.
Mine is the new Made in Romania version with the old design box.

Overall is like the more hifi ATH-R70x, tonality is very similar with less bass and more cleaner treble and mid.
R70x's treble is slightly grainy, edgy tho.

 

[Mike F]

Finally got mine for 345$ with no warranty, the unit is 100% new unused.
Mine is the new Made in Romania version with the old design box.

If it has the old box design it will be the the old version made in Romania - unless there were some new ones that came in the old boxes........

Can you post some pictures?