[Levanter]

https://en-us.sennheiser.com/headphones-audiophile-high-end-hd-660-s

Price: $499.95 USD

Technical Data
Impedance - 150 Ω
Connector - Stereo jack plug, gold-plated 6.35 mm, unbalanced, 3-pin 4.4 mm, balanced, 5-pin Frequency response - 10 – 41,000 Hz (-10 dB)
Sound pressure level (SPL) - 104 dB at 1V 1kHz
Ear coupling - Over-ear (circumaural)
THD + N, total harmonic distortion and noise - < 0,04% (1 kHz, 100 dB)
Transducer principle (headphones) - Dynamic, open
Weight w/o cable - Approx. 260 g (without cable)

A new audiophile versatility
The new HD 660 S lets you enjoy sophisticated audiophile sound in even more listening situations. The successor of the legendary HD 650 excels with the improved performance of its new transducer design. Thanks to its lower impedance, it delivers reference-class sound also when connected to hi-res mobile players, thus offering much greater versatility. The HD 660 S is an elegantly designed piece of high-quality engineering that indulges the demanding listener with aural precision and great wearing comfort.

Sound for the passionate music enthusiast
Made for the demanding listener, the HD 660 S surpasses the exceptional performance of its predecessor, the legendary HD 650. With a crisp bass, excellent mid-frequency response, and a gentle, pleasantly natural treble, the HD 660 S has an expressiveness that immerses you in every emotion and nuance of music. Still, it always stays exceptionally accurate and transparent.

Cutting-edge Sennheiser technology
The HD 660 S features a new transducer design developed by Sennheiser. This results in improved control of the diaphragm movements thanks to a specially manufactured precision stainless steel fabric, which is adapted to the contour of the diaphragm. Extremely light aluminum voice coils ensure the highest impulse fidelity. The transducers are carefully selected and paired by hand to ensure consistently narrow (±1 dB) tolerances.

Supreme connectivity
The HD 660 S has been created to enjoy music in supreme quality and from many different audio sources. Thanks to its low impedance it also offers reference-class fidelity with hi-res mobile players. Naturally, the HD 660 S reveals its full potential when it is connected to the balanced outputs of a dedicated headphone amplifier such as the HDV 820 or to the balanced output of a mobile digital audio player. Accordingly, it comes with a choice of cables for just about any occasion. All cables are made of highly conductive OFC copper, featuring very low handling noise and sturdy para-aramid reinforcement.

Designed for high-end comfort
Everything about the HD 660 S makes listening a pure pleasure – not least its strong yet lightweight open construction. The elliptical ear cups are shaped to follow the anatomy of the ear, while thick padding on the headband and the replaceable ear cushions guarantee hours and hours of listening in supreme comfort.

Initial impression & FR graph from Jude:
https://www.head-fi.org/threads/sen...sor-for-the-hd650.862308/page-8#post-13786777

 

[XERO1]

God, I hope these aren't some kind of hoax/vaporware.

If these are real, then this is amazing news! It's just really strange that Sennheiser hasn't announced anything about them yet.

Guess we'll all just have to wait and see how this plays out.

 

[Levanter]

God, I hope these aren't some kind of hoax/vaporware.

If these are real, then this is amazing news! It's just really strange that Sennheiser hasn't announced anything about them yet.

Guess we'll all just have to wait and see how this plays out.

It was at a Headphone Heaven event in Netherlands. Since more than 1 person comment they heard the 660S there is a good chance

 

[junki]

I'm not sure why OP decided to copy and paste text from the source discussion rather than link the full discussion itself: http://diyah.boards.net/thread/1660/sennheiser-hd660s-he1

Reports are neither scattered or sketchy. Solderdude is a very reputable individual, being the author of the 13MB HD650 modding PDF.

And yes, another person was able to audition the HD660S and he jotted his thoughts on page 3 of that discussion.

 

[Levanter]

I'm not sure why OP decided to copy and paste text from the source discussion rather than link the full discussion itself: http://diyah.boards.net/thread/1660/sennheiser-hd660s-he1

Reports are neither scattered or sketchy. Solderdude is a very reputable individual, being the author of the 13MB HD650 modding PDF.

And yes, another person was able to audition the HD660S and he jotted his thoughts on page 3 of that discussion.

Read what I wrote. I already mentioned I am not sure if linking to other forums is allowed.
And yes, the first initial report was from Reddit through someone else (not solderdude).

 

[XERO1]

Oh wow! This is starting to look pretty legit !!

According to the original source, it's essentially a matte-black, retuned HD 650 with a little more sub-bass. They will come with a SE and a balanced cable, and they should be officially announced sometime later this month!

These babies better be real or.....

 

[ubs28]

The clamping force shouldn’t be an issue if it is like the HD 650, since with the HD 650 you can strech the metal band which reduces the clamp.

 

[ubs28]

Wow! This is starting to look pretty legit !!

According to the original source, it's essentially a matte-black retuned HD 650 with a little more sub-bass, it will come with SE and balanced cables, and it should be announced some time later this month!

These babies better be real or.....

I see. So they added more harmonic distortion to the HD 650, just like what they did to the HD 800 S I assume?

 

[XERO1]

I see. So they added more harmonic distortion to the HD 650, just like what they did to the HD 800 S I assume?

According to Solderdude, who spoke with the rep about them, they use a new retuned version of the driver.

So hopefully, Sennheiser won't make the same mistake twice.

 

[TMRaven]

HD650's bass is already pretty distorted down low. I hope they didn't add harmonic distortion to it to give the perception of more sub-bass. Re-tuning the HD650 sounds bad too, it has one of the best tunings of any headphone on the market, if not the best tuning.

What we need is an HD650 with the same tuning, but just more technicalities down low and up high.

 

[Beagle]

God, I hope these aren't some kind of hoax/vaporware.

If these are real, then this is amazing news! It's just really strange that Sennheiser hasn't announced anything about them yet.

Guess we'll all just have to wait and see how this plays out.

You can find them with the HD820 closed model.

 

[XERO1]

You can find them with the HD820 closed model.

Hey, that one's gonna happen too, man!

 

[XERO1]

HD650's bass is already pretty distorted down low. I hope they didn't add harmonic distortion to it to give the perception of more sub-bass. Re-tuning the HD650 sounds bad too, it has one of the best tunings of any headphone on the market, if not the best tuning.

What we need is an HD650 with the same tuning, but just more technicalities down low and up high.

Solderdude posted a little more about the driver and said that it looked physically different that the one used in the HD 650.

 

[Beagle]

So I guess Sennheiser dumped all its old 650 stock on Massdrop for the 6XX, to make way for this?

When I see an HD8XX on Massdrop, I'll start saving for the 620

 

[XERO1]

So I guess Sennheiser dumped all its old 650 stock on Massdrop for the 6XX, to make way for this?

Not a chance. There's no way in hell they'd kill off a cash cow like the HD 650.

They're just putting some bright red lipstick on it and calling it 'new and improved'! JK!!