[DougD]

Actually quite a few people with the same opinion.
This review here is the odd one out.

"A review is a review is a review" is just as untrue as "a headphone is a headphone is a headphone."

No offense against any of the other commentators whose reviews you've read ...nothing in your previous comment suggested that you have listened to the HD-660-S yet, and neither have I ... but we would be very hard pressed to find someone who knows and loves the HD-650 more than Matt TCG does.

And so when Matt TCG sets up to determine whether the HD-660-S is an improvement over the venerable HD-650, that's an opinion I take seriously.

YMMV of course.We all have our sonic preferences, prejudices and internal value scales.

 

[joeexp]

"A review is a review is a review" is just as untrue as "a headphone is a headphone is a headphone."

No offense against any of the other commentators whose reviews you've read ...nothing in your previous comment suggested that you have listened to the HD-660-S yet, and neither have I ... but we would be very hard pressed to find someone who knows and loves the HD-650 more than Matt TCG does.

And so when Matt TCG sets up to determine whether the HD-660-S is an improvement over the venerable HD-650, that's an opinion I take seriously.

YMMV of course.We all have our sonic preferences, prejudices and internal value scales.

It’s just one person’s opinion.
There are other 'commentators', who know a little about headphones too.
I am listening to my HD650 every day.

It's good to keep an open mind.

 

[MattTCG]

It’s just one person’s opinion.
There are other 'commentators', who know a little about headphones too.
I am listening to my HD650 every day.

It's good to keep an open mind.

This is true. When you can't audition though, most hobbyist will need to rely on reviews. It's best find a reviewer that has similar preferences to your own so at least you have a good idea of what something will sound like.

 

[donunus]

Until today do you still like the 660 more than the 650?

 

[whirlwind]

The Sennheiser hd650, and somewhat to a lesser degree the hd600, hold a legendary status in the headphone community. More than a decade ago they brought comfort, ergonomics, build quality and most of all a level of fidelity that was revolutionary, to the world of headphonedom. Not only did the hd650 set a bar that would take years to compete against but much to the delight of many owners, the 650 “scaled up” with aplomb when plugged into TOTL level headphone amps.


The hd650 was a marriage made in heaven with high impendence tube amps. Case in point, the Bottlehead Crack was just about a perfect fit for the hd650 and has long since been a community favorite pairing. And then they are many who will tell you that the 650 will scale even higher when paired with boutique level amps like Eddie Current and other similar mega-buck amps. Unfortunately, those amps reside on the desks of a very niche group of hobbyists. What about us mere mortals who must settle for more modestly priced upstream gear, but still want to hear the very best that the 650 has to offer? Sennheiser may have delivered the answer as they usher in the next iteration of the hd6x0 family, the hd660 S. Has Sennheiser finally delivered a new King to dethrone the venerable hd650? Let’s find out.

I was able to ask a few questions about the newly released hd660 S of Sennheiser representation Everette Manns. Here is the short version of our Q&A.


1. Is the driver/transducer for the hd660 S based and adapted from the hd700 driver? If so, what was the reason?


There definitely is a trickle-down benefit from the development of the HD 800, HD 700, and HD 800 S, however the HD 660 S driver has its own part number.

2. Will the hd650 or hd600 be discontinued?


The HD 660 S is intended as an upgraded HD 650 and replacement, however the situation may be like the HD 600 and “we shall see” if all models continue to sell, for now.


3. Is there a slight difference between the pads on the hd660 S slightly different from the hd6x0? If yes, what is the purpose of the change/design?


The pads on the HD 600, HD 650, and HD 660 S all have the same replacement part number, though there may be differences between fresh and worn pads to account for people’s observations. Our purpose is always in optimizing sound quality and comfort.

4. If the purpose of the 150 ohm driver is to make it more accessible to lower powered amplifiers, did Sennheiser consider including a shorter more portable cable for such use?


The purpose of the more efficient, 150 Ω driver is to bring its optimal amplification requirements down to a wider range of amplifiers. You could say, no more veil. The HD 660 S is now indeed in the domain of high quality DAPs to drive it without an extra Amplifier, but we felt the headphone was still best used at a stationary location and included the normal longer-length cables to facilitate that. The shorter cable that comes with our HD 650 & Groove bundle is also available as an optional accessory, for those who want it.

5. What are the plans for offering the hd660 on Amazon, if any?


The HD 660 S will be for sale at participating retailers, like Amazon and Best Buy, soon. We are building up stock, and trying to keep our own stores in stock first, but we should have a boatload of stock reaching the USA soon.




So, with the formalities out of the way, let’s get right to the sound.


Bass: The hd660 S is a very good sounding headphone and produces sound in the lower register very well. The overall signature is very much akin to its sibling the hd650. But there are some differences that need to be discussed. One of the few weaknesses of the hd650 is the somewhat muddy bass, or as some refer to it as “wooly.” The bass response with the hd650 simply lacks a bit of definition that gives “texture” to instruments and voices that occupy the lower register. The hd660 S improves on this fault with bass response that is reproduced in a cleaner fashion lending way to better low frequency response.


Mids: Ever hear the phrase, “if it ain’t broke, don’t fix it.” Well, it would be folly to tinker with the luscious mids of the hd650 when it comes to the hd660 S. And Sennheiser essentially left them the same. Mids on the hd660 S are natural and organic, offering some of the best vocal reproduction in the hobby. Voices and vocal inflections are startlingly good and downright captivating for those who enjoy listening to vocal centric tunes.


Treble: The upper register takes on a different flavor with the hd660 S. Highs are crisper and more energetic than you’ll find on the hd650. Treble extends more easily and naturally with this headphone, but never does it sound harsh or strident. This helps alleviate another slight shortcoming of the hd650. If you happen to fall into the dreaded hd650 “veiled” contingency, you may appreciate the added clarity of the hd660 S. Some might be wondering if the hd660 S sounds more akin to the hd600 with the presence of better treble. To these ears, I would say not quite. I was never able to come to grips with the signature of the hd600 and it’s treble was bothersome to me. But the treble response of the hd660 S doesn’t bother me in the least. In fact, I quite enjoy it.


Miscellaneous: While the phrase “beauty is in the eye of the beholder” certainly smacks of truth, the new matte black paint job on the hd660 S is pretty sexy to these eyes. I just love the new look.


And now we may have come to the biggest discrepancy between the 650 and 660…the impedance difference. The hd660 has exactly half the impedance of the hd650, at 150 ohms. Unless you happen the own one of the afore mentioned mega buck boutique amps, I’ll call the impedance change a good call by Sennheiser. I appreciate that I can power the hd660 S from lesser amps or even a good DAP and get an exceptional level of fidelity. The hd660 S is even enjoyable from my smart phone, allowing me to use it around the house or watching a ballgame on tv with just a DAP…very nice!




Subjective Impressions: I really like the hd660 S and in fact, I do prefer it to the hd650 that I’ve owned for a number of years. Some of the mods and EQ that I used with the hd650, I don’t find necessary with the hd660 S. Out of the box, the sound from the hd660 S works very well for me and gives me an instant connection to the music. The improved treble extension and more textured bass are nice improvements, albeit modest ones but appreciable nonetheless. When you get to this level, often small improvements are somewhat of a big deal.


And then there is the price. It would be foolish not to consider the hd650 (currently $305 on Amazon) and the hd6xx (a shocking $200 on Massdrop). This might leave some wondering why pay so much more for the hd660 S. I can only answer this question for myself. First, I appreciate the subtle sonic improvements. Audiophiles, myself being a guilty party, have paid a lot more for improvements that have panned out to offer far less. Second, it’s convenient to be able to power the hd660 S relatively easily giving me an opportunity to enjoy it more often. Lastly, the new looks are quite spiffy looking and tickle my fancy in a nice way. Remember that the hd650 debuted for the same retail price as the hd660 S is now being offered for. I like this headphone and it will definitely be going in my collection.


The 660 S is an exquisite balance between musical and resolving. To my ears, it is more transparent and digs deeper into the recording than the hd650. But this difference will vary based on your upstream gear. With an exceptional amp, I’d give a slight nod to my trusty hd650 for overall sonic performance. But with my current upstream gear, there is simply more details and layers to be enjoyed and savored as I churn through my music collection when using the hd660 S.


Gear used in this review:


Amps: Bottleahead SEX 3.0 with CS4 upgrade, Questyle cma800i, Magni 3


Source: Schiit Modi MB


Miscellaneous: Schiit EITR

​

Very nice review Matt.

The headphone looks wonderful in that all black look.

 

[MattTCG]

Very nice review Matt.

The headphone looks wonderful in that all black look.

Thank you kindly. Props go out to gbeast for the pics. He has talent.

 

[DonJeremy]

Not quite the review expected...

The HD 660 S doesn't quite live up to the high expectations and lacks in various aspects according to other sources.
The HD 660 S was felt to be brighter but lacking the nuanced resolution and dynamic balance of the 600/650.
The HD 660 S apparently doesn't scale as well as the H650/600/6xx either.

But hey. The HD 660 S isn't a bad headphone, just not better than the HD600/HD650.
Just like the HD800 S isn't better than the original HD800.
Quite disappointing really.

No rush to 'upgrade' anytime soon.



On the plus side - the HD660 S certainly looks smart....

Agreed, my favorite is still the HD600 compared to 650 and 660S.