Sennheiser x Massdrop HD6XX Review / Preview - Head-Fi TV
Nov 3, 2016 at 11:13 AM Thread Starter Post #1 of 4,137

NOTE: If you can't see the embedded video above, please CLICK HERE to see the video.

Today, Massdrop is announcing the Sennheiser x Massdrop HD6XX, which is essentially the Sennheiser HD650 with minor physical differences and a different cable. We've confirmed it's the same headphone (confirmed with listening and measurements, which you'll see in the video), only now it's a lot more affordable.

The Sennheiser x Massdrop HD6XX lowers the price of entry into world-class headphones, starting today.

EDIT 2017-06-27 1705 EDT:
The Sennheiser x Massdrop HD6XX drop is back! However, at the time of this writing, there is only one day left. Supplies permitting, you can still get in on this drop by clicking on the following link:

Products mentioned in the video:

Sennheiser x Massdrop HD6XX Review / Preview produced by Joseph Cwik, Brian Murphy, and Jude Mansilla
Last edited:
Nov 3, 2016 at 11:14 AM Post #2 of 4,137
Here are frequency response and THD measurements we made of both the Sennheiser x Massdrop HD6XX and the Sennheiser HD650:

NOTE: The measurements above reflect diffuse field correction.

They do sound the same, and those measurements certainly support that.
Audio measurements were made using:
  1. Audio Precision APx555 audio analyzer
  2. G.R.A.S. 45BB-12 KEMAR with anthropometric pinnae and low-noise ear simulators
  3. Rupert Neve Designs RNHP headphone amplifier
  4. Herzan acoustic enclosure (custom)
Nov 3, 2016 at 11:25 AM Post #3 of 4,137


Headphoneus Supremus
Feb 21, 2007

There's really not much to say this time around. It's just so obvious. But I'll throw in a few words anyway just so my post isn't purely pictures. 
Massdrop has carved out a niche in releasing their own versions of iconic headphones, with some unique properties and spectacular prices. First came the AKG K7XX - a ninja-black take on the K702 65th Anniversary Edition which had an MSRP of $499 just a few years back. Then came the Fostex TH-X00, a customized version of the classic Denon/Fostex woodies we all know and love. Denon's D5000 used to sell for $699 and the Fostex TH-900 was $1299 before they discontinued both models. The Massdrop version, not identical to either but certainly competitive with both, sold for $399 (and later $449 with an arguably fancier wood). 
You sense the theme here? Excellent headphones with some custom touches selling for prices far lower than expected - in some cases even lower than used prices on the original models themselves. There's also been a specialized CIEM collaboration with the Custom Art brand, an early exclusive with the AKG K553 Pro, and a specially commissioned DAC/amp called the Grace Design m9XX. Clearly Massdrop "gets it" on a level very few others do, to the benefit of the entire headphone community. 
Well, Massdrop is at it again, this time with the iconic Sennheiser HD650. One of the most loved and commonly owned "high-end" headphones ever, the HD650 needs no introduction. I used quotes for "high-end" since there are now so many more expensive models available that we sometimes forget how long the HD600 and HD650 were on top of the food chain. For several decades, if you wanted a high-end headphone without spending crazy-money on something like a Sony R10 or Audio Technica L3000.... your main choice was the HD600/HD650 duo, followed by the AKG K701, beyerdynamic DT880/990, Grado RS-1, and on down the line. But in my mind the Sennheiser duo was the first and most obvious path that most people followed. 
It's also interesting that the Sennheisers have experienced something of a resurgence lately. Lots of headphone enthusiasts I know, fed up with the latest and greatest models with their huge price tags, have gone back to using HD600 or HD650 as their primary headphone. HD800 and HD800S may be the "better" headphones in some respects but a lot of folks still enjoy the 6-series more when it comes to real-world listening. And I totally get it - the 6-series does so much right, and perhaps more importantly, so little wrong, that it still makes for an easy recommendation after all these years.
That recommendation is about to get easier thanks to the new Massdrop Sennheiser HD6XX. They start with an HD650 - made in Ireland just like the regular version - add a sweet new stealth paint scheme, a redone cable, and some other minor aesthetic touches, and price the whole thing for just $199. Yes, $199. That's an insane value right there! I've (happily) paid more for used HD650 examples on more than one occasion. To put that in perspective, the original HD650 MSRP is still $499, with street prices at most places being $399, and deals coming around here and there for the low-$300 range. So $199 for this unique version is an absolute steal in my book.
The HD6XX paint scheme is called Pantone Black 6 XGC, but it's actually more like a very deep midnight blue. It seems nearly indistinguishable from black until you look in the proper lighting. The HD650 logos on the sides, normally silver with darker gray lettering, are now black with silver text. The "Sennheiser" text across the top of the headband is black instead of white, making it very subtle in contrast to the midnight blue. There's a Massdrop logo on the inside of the headband above the right cup, and on the other side will be the serial number. This initial batch is limited to 5,000 units, so don't miss out. I imagine there will be more down the road but it will be a while. The first 500 orders placed will be guaranteed a serial in the sub-550 range, in case that matters to you. Not sure if it becomes randomized after that or not.
The redone cable is pretty much the same cable as before but chopped into a shorter, more manageable length, and terminated with a 1/8" plug. These aspects make it more useful in day to day listening as far as I'm concerned, and you can always add the (included) adapter for 1/4" use if needed. Or grab a cable extension for across-the-room listening if that ends up being something you do. Massdrop says there will be an option for a balanced ZY branded cable at additional cost when checking out. I don't have the price available but that could be useful if it ends up being a good deal. Or, visit any one of the many companies out there who make HD650 cables. Moon Audio, Toxic Cables, Effect Audio, Signal Cable, Cardas, Norse, C3, WyWires, ... the list is massive. I've been hearing a lot about Impact Audio and their very affordable cables lately so that's something to look into as long as we're talking about great value. But, as stock cables go, this one is not stiff or annoying like some others, so most people will be fine with it. 
And that pretty much covers it - a nicely customized HD650 with an extremely welcome price. What more could we ask for? The parts are all replaceable and interchangeable with HD650/HD600 parts, so this is an investment which should last a lifetime of heavy use. Sennheiser even covers it with a 2 years warranty which I assume applies to the original buyer. As usual for Massdrop, orders are placed now, with payment collected after the drop ends. Headphones should ship by 12/15 which means domestic customers will have their in time for Christmas. International shipping might make it depending on where the package is headed. 
And now, some eye candy. Keep in mind how well the HD650 scales with better sources and amplification - I'm using sources from Aurender, Matrix, and SOtM, and DACs from Esoteric, Resonessence Labs, and B.M.C., along with a wide variety of amplification from Pass Labs, Cayin, Simaudio, Violectric, and others. The HD6XX isn't terribly picky in the same way as the K7XX, but at the same time it will massively reward you as the chain improves. I like it quite a bit off the Acoustic Research M2 but even the little Pono and iBasso DX90 do a pretty decent job. This is definitely a headphone that will grow with you as your system improves over time. Well done Massdrop!




Nov 3, 2016 at 11:38 AM Post #6 of 4,137


My name is grizzlybeast and I'm an audioholic.
Dec 26, 2012

Massdrop x Sennheiser HD 6XX Headphones


Let me start of by saying this is not what I would call a real review. This is more like a Tribute to a headphone that, while controversial, has been and is irrevocably deemed a classic reference headphone. Not just my posts but many reviews have referred to it or used as a headphone to compare it to.  The disclaimer is that I have known about this release for a while now and have been sent  a pair. Even so, given my long relationship with several pairs of HD650's I have no reason to shill these along side the fact that they will sell out very quickly anyhow. 

Tribute / Appreciation
I have had 6 pairs myself with the HD6XX being my seventh pair. I have bought and sold this headphones for a myriad of reasons. It always seems to end back up in my stable because I have come to know it as consistently more spot on in tonality than just about every headphone I have heard. Some of the reasons for me selling them so many times was because I sold it them to help fund a new piece of gear or was in a honeymoon phase of something new that outperformed it in a particular attribute. Then later when I knew I had lost my bearings on how things were supposed to sound I would repurchase it again. 
Why were people asking if the Focal Elear was the super 650 they have always wanted?
Why do people ask if the the new ZMF Atticus are the closed back HD650's they have been longing for?
Why when the Audeze LCD 2 was released was it called the planar magnetic super HD650?
Could it be because  they are more expensive headphones with a darker than neutral signature? Well if so then why is it much less popular for someone to ask for a super Beyerdynamic DT880? or a super Hifiman HE-500 even? Such an opinionated and categorically diverse thing as music can't possibly have one tuning unanimously crowned as champion can it? Uhhh... well if it did, love it or hate it, like it or leave it, buy it or sell it, the Sennheiser HD650(or even HD600) is unequivocally the closest thing to having that crown as far as headphones go. Sure the HD800 is technically better but just because the prince is younger, brighter,  and faster doesn't make him king. The king would have to die first and as far as that goes the HD650 is apparently immortal. Relatively, the 600 is the more even tempered queen right by his side. 
Let's take a look around the web shall we:
This is without searching specifically for the HD650 but rather "best reference open back headphone". Some have their preferences but there is one consistently present.

"6. Sennheiser HD 650

If there is one pair of headphones in the World, synonymous with high-end sound…

It’s the Sennheiser HD 650.

A long time favorite in both audiophile, and pro audio circles…

These headphones have perhaps more great reviews than any model on this list." 



Studio / Professional usage:
"Lightweight aluminum voice coils are usually the standard for studio headphones in general, and with these being open-designed and holding a high reputation for an even frequency distribution, it’s the go-to for most professionals. " 

"1. Sennheiser HD 650


Sennheiser is a top audio company that produces numerous high end headphone lines in a variety of price ranges. While the Sennheiser signature sound is great across price points, their midrange open back Sennheiser HD 650s are a particularly great value.


  1. Balanced and natural sound
  2. High dynamic range
  3. Lifelike spatial imaging


  1. Open-ear design does not contain the sound
  2. Headband can be a little tight
  3. Requires a capable amplifier to drive"
"The 650s offer an extremely detailed sound with clear separation and timing, dealing equally well with all kinds of material. I particularly liked the bass response, which was very smooth, extended and full, translating well onto larger systems. I'm currently living and mixing in a temporary space (with poor acoustics), where monitoring has been a problem — and in this situation, I'm more confident mixing with HD650s than on my monitors, and have found that my mixes are translating better than ever. My pick of the bunch — which I've bought since trying them out."
Jules Harding

Thought this one was interesting  on the 600

"1) Sennheiser HD 600

Sennheiser HD 600

  1. MSRP: $509.00
  2. best price: check amazon! | check eBay!
  3. type: open back
  4. fit: circumaural (over ear)
  5. impedance: 300 ohms
  6. frequency response: 12 – 39000 Hz
  7. material: metal grilles, carbon fiber, velour ear pads
  8. color: speckled blue finish, black


What more can be said about these? Well I’ll tell you! For starters, they may be the best reference headphone that you can buy. This is across the board pretty much a consensus among-st audiophiles. I will never forget the first time I read this review on amazon. "


A quote from one of all of our favorite sources:
- "Well...they've changed their tune a bit with the just announced Massdrop Sennheiser HD 6XX because in this case they didn't change the headphone's tuning it at all. (Measurements show the HD 6XX and HD 650 essentially identical within measurement errors.) No, there is really no reason for them to re-tune the Sennheiser HD 650. They've done their homework. They know that this is widely considered amongst headphone enthusiasts the standard by which all other headphones are compared. I've reviewed them and love them. Yes, there are better sounding high-end headphones, but none deliver the price/performance ratio of this icon."


Looks / Comfort / Build

  1. Ear pads out of the box are slightly firm but deep and create a healthy distance between the driver and the ear.
  2. The ergonomics have proven to be timeless and are a succession of previous designs used by Sennheiser
  3. I won't mention the names of other manufacturers but I dare you to find a 650 that was delivered broken through shipping. If it does happen it is a lot more rare than with ____. You fill in the blank. 
  4. The clamp pressure can be a bit imposing out of the box. 


  1. Very dynamic and punchy without sounding aggressive. (Amp dependent so results may vary)
  2. Good Microdynamics
  3. Great Details
  4. Non Fatiguing
  5. A chameleon with down stream and upstream gear so heavily manipulatable. 
  6. The treble can be grainy and/ or slightly dark to some but is smooth in balance with good resolution and extension
  7. Wonderful midrange from the lower midrange all the way through to the lower treble
  8. The bass is a bit rounded with a slight mid bass elevation for healthy kick drums
  9. The sub bass can sound ill extended at times but for the most part is capable of handling even sub bass saturated genres(yet not effortlessly)
  10. Can be modded to have very tight and controlled bass, even better clarity and cleanliness (very easy to mod)
  11. Can sometimes sound slow and veiled to some when not properly amped or in stock version. 
  12. Very scalable and reportedly becomes competitive with Top of the Line headphones when used with uber quality amplification
  13. Soundstage can sound narrow to some but maintains adequate depth and layering for  relatively deep insight into recordings. However, in the grand scheme of open back headphones it usually sounds less wide and is said to have a small soundstage. Again, amping really helps the depth of soundstage increase. 
  14. Though some believe it is a darker sounding headphone, It really works well with OTL tube amps and is revealing of system changes and improvements. 




There is a coin mod to be done by using a quarter to cut out a portion of the foam covering the drive; a removal of the back cover and adding Dynamat in specific places; and a  removal of  the foam from the back of the driver. (please put the cover back on). Be sure to scour the internet for more specific instructions. Rest assure that these mods are all VERY VERY easy. There are all sorts of mods..even some to make it brighter. 
The mods can give the following improvements:
  1. Increase of bass control and perceived reach
  2. More satisfyingly visceral bass slam
  3. Increased speed
  4. Faster Decay
  5. Crisper and livelier sound
  6. More openness and clarity
There may be more improvements and mods to do so this is by no means exhaustive, and again just a little boost to get you started. I personally heard the HD6XX and thought that they changed the tuning until measurements confirmed that they actually are the same HD650. I had become acclimated to the tuning of my modded 650 so upon arrival I was very disappointed with the stock bass in comparison as well as felt the headphone sounded slower. For 199 the HD6XX is a no brainer and a modded 650/6XX one will become legend if it already isn't by now...the stock version most definitely is. 


Amps I have heard the 650 on and personal rankings (of the pairings not the amps themselves)

  • Apex Teton
  • Trafomatic Head 2
  • Ifi iCan Pro 
  • Bottle head Crack and Speedball upgrade/ Schiit Jotunheim 
  • Cayin iHA-6 
  • Airist Audio Heron
  • Nuprime HPA-9 (a bit dark for it but good body)
  • NFB - 28

[size=20.007px] HD6XX VS HD650[/size]​
The aesthetics and accessories are the only thing to compare here really. But eh..why not?
  1. The 650 comes with a longer cable terminated in XLR and an adapter for 1/8 jacks
  2. The 6XX comes with a shorter cable terminated in 1/8 inch and has a 1.4 inch adapter. Why... possibly to be more compatible with portable amplification and transportable systems. Because by no means is it competitive with 'Beats' since people with those headphones most likely wont be using any amplifier
  3. The 650 will still have the more luxurious or classy paint job as the 6XX is a plain midnight blue that can look black depending on the lighting used. 
  4. Through and through the build quality is the same and they measure the same as well 


When I created the "Massdrop Collaborations...What If?" thread almost a year ago I expressed how my choice would be for a 650 collaboration. While not quite black, I am sure Sennheiser had their reasons and I am very happy that this headphone is available at price lower than I have ever paid even for a used pair. These are good times to be an audio enthusiast. Not to mention the most recent release of the Schiit Jotenheim, now Music lovers can have a system I used to dream about for a lot less than a new 650 and Bottlehead Crack w/ Speedball upgrade would have costed you back then. I feel very humbled to have been able to witness this re-launching of an industry legend and know tons more people will be smiling from ear to ear as they listen to music "the right way" lol.. just playing anyway you choose is the right way for you.
Nov 3, 2016 at 11:40 AM Post #7 of 4,137


1000+ Head-Fier
Feb 17, 2014
Edmonton, AB
Hmm, is this an indication that Sennheiser is releasing a new or updated HD 600 series addition in the near future and are moving out old stock, much like the HD 598 SE?
Regardless, that's one heck of a bargain!

Nov 3, 2016 at 11:56 AM Post #12 of 4,137


Headphoneus Supremus
Dec 19, 2011
Motor City, USA

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