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The Sennheiser HD 650 - Greatest Ever... Really?

A Review On: Sennheiser HD 650 Headphones

Sennheiser HD 650 Headphones

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Price paid: $499.00
The Fed
Posted · Updated · 400052 Views · 29 Comments

Pros: Smooth Presentation, a linear, stout sound at louder volumes.

Cons: build quality is meh! Overall sound is too recessed and lacks weight

The praise that has been heaped upon the Sennheiser HD650 headphone is something that probably every headphone OEM envies. The HD-650 is nearly a decade old and yet is still viewed by many as a top tier dynamic, worthy flagship, and is the benchmark that many measure price to performance ratio against.


I personally was cruising along quite happy with my set up… Running almost exclusively between Denon D5000’s and Ultrasone Pro900’s. I felt I had the best of both worlds. Since I love the visceral impact of good bass in my music, these two pieces seemed to be perfectly tailored to my listening habits.


The Denon gave me a little more reasonable treble energy and a little less sibilance when I needed it for something more complex and diverse. While the Pro 900 gave me that sub woofer for your ear feel that just flat out slams your ear drums. With a decent DAC/ desktop amp set up I am usually able to apply a 6kHz to 8kHz cut to smoothly equalizes the sound to eliminate that “ESSS” sounding ear razor that the Pro900 is so infamous for.


However somewhere along the way the constant gushing over the Sennheiser HD650 got to me. Specifically Mike from Headfonia repeatedly claiming that it was the ultimate king of bass impact…. He never said king of bass quality, quantity…. He always spoke of the HD650 in terms of “Impact”.This should get just about any hard core and well funded bass head’s juices flowing and so I began looking at the viable options for acquiring this apparent low frequency giant. And so after parting ways with most of my portable equipment, I was flush enough with cash to purchase my own set of the venerable HD650.


I will start out by saying that because of all the talk of the ‘luscious mids’, smooth highs and world class low frequencies my expectations with this headphone were near off the chart…. I have since done the same thing with my first attempt at the  Audeze LCD2. The LCD2 albeit a very good headphone, was so overblown in my mind that by the time I actually listened to it, I was disappointed. That had far more to do with my overblown expectations than anything... because second time around... being aware of how much darker the LCD2 was than its Hifiman counterparts.... I have found a place for the LCD2 in my stable.


But by the time the Sennheiser headphone had finally arrived, it was competing with dare I say unrealistic and extreme expectations and was pretty much behind the 8 Ball from the start.


Build & Design


The Sennheiser HD650 is certainly a dated design. There are dozens of headphones on the market in the same price point that are better dressed. Most $500 headphones have premium materials such as aluminum, leather and wood worked into the build. The Sennheiser headphone is almost exclusively plastic. It is a shiny, cheap feeling plastic on virtually every exterior surface sans the grill, ear pads, retainer ring and bottom of the headband. Detail items like the "Left" and "Right" indicators are simply cast into the grey plastic.... This build quality seems unfit for a legacy flagship.... Obviously its been a long time since this headphone was brought to market and Sennheiser was working in the pre-Beats era, long before headphones were valued as a fashion accessory and long before OEM's thought they could bring flaghips to market with price tags north of $1000. Sennheiser's HD800 and HD700 show they clearly can design a top tier headphone both in sonic character and design quality, but the HD650 is still asking $500 USD and doesn't give you a warm and fuzzy out of the box once you've got it in your hands, at least it didn't for me.


The headphone is extremely light. Many in the community would give it points for this and they are certainly entitled to their opinion. However I personally see this as a demerit. Speaking strictly in terms of assessing an items value from a subjective/ aesthetic viewpoint, the Sennheiser headphone appears to be made of cheaper, less durable materials. I am not going to strain my neck if a headphone is north of 400 grams. The Hifiman HE400 weighs in at a hefty 440 grams and is perfectly comfortable to me, the Denon D5k weighs in around 360 and is probably the most comfortable headphone I've ever worn. If one is spending $75.00 on a beater set of portable cans, an expendable gamer headset or a cheapie like Superlux or Porta Pros (of which I am a fan)  then by all means they should be and can be as light as a feather and made almost exclusively out of plastic without raising eyebrows. But at $500 out the door for a would be flagship headphone that was intended for listening at home or in a studio through a serious system... I don’t know.... I expected something more substantial.


The crux of this featherweight value is that in order to keep it properly seated on the listeners head, Sennheiser had to crank up the clamping force. Otherwise the light weight construction leaves it prone to moving too easily as it has little resistive value on its own. The clamping force is something that many have commented through the years as a supposed 'death grip'... Once again just like the HE400 won't snap my neck, the clamping force on the HD650 is not going to crush my skull. It is certainly wound a bit tighter than most, but I personally believing the clamping force has been measured perfectly to counteract the lightweight construction's tendency towards moving easily. It is a goldilocks value.... not too much, not too little... Just right. This is a nod to the design engineers.


Right off the bat my delusions of grandeur were dispelled. It is certainly nicer looking than its faux marble clad brother the 600 however as a supposed flagship headphone of such universal praise, I was underwhelmed by the look and build quality. Those who think this is immaterial are kidding themselves.... Aesthetics have value to the consuming public and audiophiles are most certainly not immune... The hifi world is littered with glitzy machined aluminum tone arms, satin metal surrounds for tweeters, anodized aluminum face plates with machine metal knobs, high gloss enamel finishes, lustrous wood side panels, frosted glass.. etc....etc...


The die-hard says that this is simply an indicator that they chose to pour all their cash into sound quality. OK maybe this is true.... lets see. 


Hook It Up! And Wait.


I did not want to be hasty with a plug and play attitude as I had heard that the out of the box, plug and play sound of the HD650 was disappointing (I heard this about 10 hours after I purchased it sadly) but that a 100 hours of burn in would get you a somewhat matured sounding headphone, so onto the vintage Realistic 64B it went. This older vintage rig is hooked up in a file cabinet at work and so can burn in a headphone out of site and outta mind while I still enjoy music on my main headphone rig…. A Violectric V100 tethered to a Laptop running JRiver via my Rega DAC with a Wyred 4 Sound uLink handling conversion duties to SPDIF. 


100 Hours - Impressions


After it had burned half the day on Thursday and all day Friday, Saturday and Sunday by the time I got in to work on Monday the 650 had clocked roughly 96 hours of burn in time. I plugged it into the Violectric V100 and listened to some newer redbook CD rips. Muse 2nd Law, Foo Fighters Wasting Light, and Gaslight Anthem The 59 Sound. 


The HD650 is not a bass head can. That is my first impression. Where the hell is this supposed ultimate bass weight?


A couple of local Head-Fiers down here in the Southland told me the 650 was really amp picky and that I would do better with a tube amp like a Woo WA6 or Bottlehead Crack. However my headphone amp is a Violectric amp which is what Sennheiser uses in their “Hall of Fame” set up and is one of Sennheiser’s Senior Project Manager Axel Grell's favorite amps for his own listening. A couple others mentioned changing the cable to a Cardas one, and one guy said I might need a different DAC to get the most out of it.


So in order to get the Sennheiser HD650 to sound good what I needed to do was:


  • Get a different amp
  • Get a different cable
  • Get a different DAC

Maybe I should get a different source, different interconnects, a new power conditioner and stop using CD's while I am at it eh? Mind you I do see where some could see this headphone as all they need and build out their entire system around it.... searching for another .5% of improvement with each piece of the puzzle... but I have already built my system(s) and am not really inclined to do a whole lot of kit rolling in order to optimize the synergy with this lone headphone when I have a half dozen others that sound fantastic through the rigs as is. 


So my immediate disappointment with the bass could’ve derailed this whole review. I was expecting Pro900 bass or Denon D5k bass without the 7khz ear razors or recessed mids... What I got was an all too polite rendition of EVERYTHING.


The low frequencies are extended, there is textural information galore, you can really hear the stick or the tom on the drum skins, the full decay of bass strings, mid range is sweet and smooth, and there is plenty, and I mean plenty, of high frequency detail and sonic information. Anyone who says the HD650 does not have enough treble energy or detail is, to these ears, not hearing straight.


But that ultimate bass weight, that Mike implicates all the time, it is not here IMHO.


The low frequency, midrange and treble are all recessed quite a bit. They do not hit you in the side of the head with impact. They don't even touch you. If this is what people are speaking of when they say the 650 is veiled then yes, it is veiled, but not in the sense that a certain portion of the frequency range is somewhat blurry or hidden.... Its more about air pressure that makes a headphone felt as well as heard. Open architecture does limit this but I've heard better open backs at giving you punch. 


I will hop on my soap box right here and say that one part of a headphone experience that is vital to me, is the overall weight of a headphones tone. I am not specifically talking about bass extension or articulation or even the bass frequencies in particular. What I am saying is that headphones with a tonal density to them…. A robust acoustic mass that move some air pressure to bring the music more to life…. That is critical for enjoying music in my book. Otherwise it sounds like music but doesn't feel like it.


It may not be critical for monitoring, mixing or mastering in a studio, or DJing or even for being an audiophile who wants to sample 24/192 and DSD audio tracks like they are a damn 10 year old Pinot Noir… but for the average Joe like myself who wants to simply strap on a set of headphones, cue up an album, hit play, sit back and enjoy some music…. The overall presentation doesn’t need to be “forward” but it needs to be felt as well as heard.


Oldies like Buddy Holly, Sam Cooke, and Bob Marley all have strong drums and bass rhythm that is presented most natural when the full weight of the instruments is presented... the kick drum and bass line at the opening of Dock of the Bay sets a strong foundation for Otis and the guitar to build off of. Alternative music like Smashing Pumpkins,  The Pixies, Jawbreaker, Dirtbombs, and Blur all have bass and drums that need punch. Punk rock and other guitar driven music like Social D, Operation Ivy, Van Halen, Bad Religion, The Ramones, Rancid, The Strokes, Vampire Weekend, Weezer, Gaslight Anthem.... they all have rhythm sections, and natural timbre that is presented best when it is presented with a fully developed full bodied sound.


Most people would rather listen to music through a great set of speakers because the music can be felt in your bones and people go to concerts because the live performance trumps every other experience. I saw Muse at Staples Center a month ago and the bass and drums absolutely rattled my bones.... Just vibrating you right down to your soul. And that is why 50,000 pack stadiums every night to see performances. Because the music overwhelms your senses. I saw the Ramones in Santa Barbara in the early 90's and it was the loudest show I've ever been to... Large Marshall double stack cabinets for both Dee Dee and Johnny and Marky's drums were mic... all in a small club (The Anaconda for anyone who cares) and the Ramones play tight so it was just a full on sonic assault.... transcendental to a young kid and still the best show I ever saw. 


To me, listening at home through a set of headphones should be a tamed extension of that experience. Obviously headphones can't give you what a live concert can... nor can they give you what well crafted speakers can, and speakers can't give you what amps and guitars and mic'd up drums can.... but each should have a measure of the other. The HD650, although tonally sweet and smooth and carrying some weight in its tone is similar but a bit more recessed than the Audeze LCD2, it just holds you too far back from the music FOR MY TASTE. It left me wanting for something more!


The HD650 often gets the compliment that "I could fall asleep with these on" and that to me sums up the HD650 perfectly.... It's kinda boring.


The HE400/ HD650 issue.


I’ve had a few people ask me which I prefer. The HE400 has a little more low end punch and the extra growl and mid range power makes it a better choice for my taste. Speaking strictly in audiophile terms the HD650 has the better acoustic chops. Its professionally damped driver fills out more evenly and more linearly but this linearity is still comes out anemic compared to the more live sounding Hifiman. . 


At lower listening levels the HE400 is a far better choice. It gives you a tad more flesh to sink your teeth into. A bit more punch in the low end and a live wire mid range that’s tipped up just enough to make rock music sound amazing. But as we travel up the volume ladder the Sennheiser becomes more stable and stout in its presentation, everything fills in evenly. The lows get stronger as the mids get sweeter etc... The HE400 although good to a point, can get crispy and its budget level planar membrane can start smearing tones and blurring separation on complex electronic fare where 100 or more different sounds are sometimes dubbed over the top of each other. The Senn is more resolving and surefooted through big sonic waves but like said, anemic... I could live with either, but if I could only have one, it’d be the 400. Even though it tends to get a little distorted when it is under powered and doesn't have that furthest reach of resolution. It's rock and roll presentation is more enjoyable.


Johnny Come Lately – The X1 P


Phillips open back X1 is priced a hundred short of the 650. But there are obvious similarities. Open back design, midrange price point. But one would assume that its beautiful aluminum cups, velvet ear pads, and leather headband come at a sonic price.


The X1 is a gorgeous looking headphone. Along with my D5000 and LCD2 it is one of my most sartorially minded. People like to contrast it against the Sennheiser Momentum…. No, the Momentum looks flimsy build and doesn’t hold a candle.


Next to the X1 the 650 looks very dated. The plastic finish is a glaring shortcoming up front for a headphone asking $200 more. The 650 is the technically superior headphone. For the same reasons the HE400 can't play this game the X1 can’t either… It doesn’t have that same surefootedness and linearity that the Sennheiser does, nor does it scale as well. But the X1 has a more rich and nourishing tone that will appeal to music lovers and bass heads alike. Its bass slams harder, it's musical vibe is just funner. It can also get a little crispy and sibilant in the upper register when volumes start creeping up whereas the 650 never breaks form. The Sennheiser is still the “better” headphone. But for a music lover like me I am not sure how important that is. Lately the X1 has been getting a ton of head time and that speaks to its engaging tone. It gives me that 'felt as well as heard' sound that I crave.


VS. My Favorites


Against both of my closed back favorites, the Sennheiser plays the same song. It is linear, well engineered, accurate and anemic. The Denon D5k and JVC DX700 are simply more dynamic more emotionally engaging, and immerse you in the music. They surround you in an envelope of tone.


The punch is there with both, but the JVC DX700 ups the ante by giving a sound stage worthy of an open back phone and providing not quite as linear but still fairly linear sound as things get louder and louder. I would choose the Denon and the JVC DX700 over the 650 every time. It simply doesn't give you as much of the song as they do. It is truncated in its presentation it sounds thin and lifeless compared to the two Japanese headphones. They are just too well rounded, dynamic and potent for the 650 (IMHO). They don't give anything away.  


Contrasting against the Japanese duo, the Sennheiser strikes me as the stuffy middle aged guy rocking a corporate polo, khakis and cheap patent leather shoes. He presents well enough in professional circles but doesn't really have the personality to charm. The 650 is the middle aged, mid level cog in the machine. The D5k and DX700 are sharp dressed 20 somethings from Tokyo with Italian cut suits and crepe sole oxfords. Their resume may not be as thick and they may not have the same number of professional accolades but they are dynamic, engaging and charismatic. They offer excitement and future glory that you will not find with the hum drum late 40's something sitting with his shoulders slouched in the lobby.




In closing the Sennheiser is by most normal youthful standards a little light in the ass. Some would call that a veil or laid back but it’s not laid back to me… That denotes a mellow, relaxing sound and a veil sounds like the treble is shelved down or certain parts are blurry. No this is about sound pressure levels. Air being moved by transducers. This is about 2 dimensional accuracy vs. 3 dimensional involvement. 


The caveat to that would be in a full size stereo rig.... In those scenarios the 650 sounds a lot better than most modern 32 ohm headphones.... The only 2 in my collection that best it on the integrated amp scene are my planar headphones... both of which have flat phase response and so don't do the poorly damped thing.... But in a typical dedicated headphone setting.... to me, the 650 is a bit boring. You are held back just a bit too far from the song to truly enjoy it. I dare say that the hype may be a bit overblown….. at the very least it does not line up very well with my taste. 


Mind you I didn't write this review to deride anyone who loves the HD650.... and I'm sure those of you that are fans of it will continue to enjoy it. But I do think there are a lot of people running around this site looking for answers, not wanting to spend their hard earned cash poorly.... and most people use this site to inform their future purchases. Because of some of the descriptive words I have heard people use, I think someone could get the wrong idea about the sound of the 650... when people call it dark, warm and full bodied.... I don't know that these words do the phones tone justice. At least not without building your entire system around the HD650. Contrasted against the greater landscape it is a bit light and lacking in body. Someone needs to say that. 


So I hope I do not get flamed but I think that someone out there deserves to get a little objectivity on this headphone rather than just more gushing about "greatest ever". No I am not a Beyer or AKG fan boy going subterfuge.. I am just an average consumer with average taste and listening habits trying to give others like me some reasonable perspective. 


I suppose if you dedicate all your resources to just this one headphone, you can make it sound spectacular.... But to the average head-fier who has the same low riding, subwoofin tendencies that I do. Who listens to Muse, Foo, the Black Keys, Gaslight Anthem, The Strokes.... modern music.... this may not be such a strong fit. 


Just saying.


Great review Ted, nice to see some critic notes to so (over)praised headphones.
But I think your review is not complete until you list headphones that are up to your liking, compared to HD650, so a fellow reader may get a better context for your review.
Fair point. I'll revise to give context.
Seems like mismatch between music genre preference and headphone than anything else
I do think that the build quality could be better but come on, do you really prefer lead on your head than feather when you listen to music on home? really?
what we need is to change some cables, foam, tubes, and reassemble the dac amp combo...and the hd650 will truly shine...like the one in my room...sonic gold. lol
I failed the first time i had the 650 n sold it.. this is my 2nd attempt.
Bravo Ted! I have had my HD 650 for about three years now hooked up to a Little Dot Mk IV tube amp and pretty much agree with you. It wasn't until I got a Beyer T1 that I noticed the difference.
@ Woid...I assume you also noticed the price difference?
I've heard the T1s and wouldn't trade my 650s for them unless it was to sell the T1s, re-buy the 650s and also get some 600s for when I wanted things a bit brighter... just my ears' preference. To be fair, I should also say I use them balanced.
UGH, More "newbies" trying to review great Audio products.........
When you can FALL ASLEEP with your Headphones on, - that means they are some GOOOOOOOOOD HEADPHONES !!!!!!
I thought that would be very clear with HD650, best Naturally sounding headphones EVER MADE SO FAR, and they have Enough of High Quality, non-fatiguing bass too !
Come on dude! Don't be an ass.
I have no problem with 650 apologists arguing their point... but don't belittle and act dismissive like other points of view are just dumb kids who don't know any better. !
Newbie... I'm friggin 40 years old and have been listening to music with headphones since I was a kid..... And beyond headphones I've been playing and listening to music seriously since forever.... calling someone  a newbie like they don't know what music "should" sound like is the tired old saw of elite audiophiles.
Sorry but to me... for $500 bucks... the Senn is a dated design with sub par dynamics....and the veil gets in the way of me enjoying my music.... And that is my point of view, with my music tastes...
I've made it pretty clear that I'm not from the stuffy Stereophile set that is playing Dianne Krall, Norah Jones, Miles Davis "Kind of Blue" and Chesky records all the time because they sound better with my equipment... I listen to my music and the equipment needs to work with my library.... not visa versa.
So I wrote the review to inform other peoples purchases... I'm sure there are plenty out there who would be disappointed if they bought the 650.... and don't have the means or desire to build an entire system around a single set of headphones. So the review is for them.... 
If you disagree... no worries... they are just headphones after all! 
But don't be a dick about it!
I don't know anyone in the know who's paid $500 for their 650s...Massdrop just had them for $349 which is closer to what most end up paying. I've heard some of the best cans around (including the ones you prefer) and have to say I just plain disagree with your assessment of the HD650s.
I agree with "laon" who commented that your preferred genres of music might not give the best impression of the 650s.
Balanced with a good cable these cans are addictive. Great recordings sound superb and poor ones become far more listenable. There are of course better cans but they cost a lot more than even the full $500.
Great review! I'm listening to them now, and while I don't totally match-up with your tonal assessment, I completely agree with your take on their distant / boring presentation. They are so smooth and unexciting that they could put you to sleep. But yes, they are very, very nice, and very very smooth, no question... but just not "there" for me.
Based on the names of artists in your review, we seem to have the same taste in music, so that probably weighs heavily in what we want headphones to do.
The tonal issue for me is that I DO think they lack adequate treble (and I think that's the main culprit of the veil), and I feel there's plenty of bass.
I want to love them but just don't so far. I'm going to give them a fair shake with the burn-in theories and go for at least 100 hours before I ditch them.
Again, a very well written review (I mean the actual writing, not just the info) and a good read.
"...a very well written review I mean the actual writing..."
I meant to say that but can't edit comments so here you go; a compliment from one who doesn't quite agree with your assessment ;)
You can actually get stupid amounts of bass detail and impact out of the HD650 but you need to listen to it through a OTL tube amp and at near earsplitting levels.
It's not healthy, but it can sound comparable to standing in front of a 20-30 thousand Watt outdoor speaker stack playing psy trance.
But no it can't emulate a 100 000 Watt speaker stack playing glitch hop/ dubstep/ drum and bass even at the highest volume levels or with any accessory equipment. (In other words at an orthodynamic or electrostatic level of bass detail retrieval)
So yes it can have unbelievable bass reproduction in certain rare situations, but no it's not the last word in bass technicality, bass retrieval or detail.
Source: Going to Shambhala Music Festival, comparing it to orthodynamic and electrostatic technology.
I have no idea why anyone would listen to the headphones that loud in their life unless on a dare.
Maybe if you're about to die and want to listen to Electric Universe - Gaijin Rocker as if it was at a live show, you can buy a system to do it with for less than 1k lol!
But seriously you would likely ruin your hearing in the process. :O
I appreciated the review and this 66 year old fart likes to feel the music as well as hear it so your review really caught my interest, especially after reading the first HD650 review and thinking these are the headphones to get. I want to feel the thump of a bass fiddle in a good jazz song or even the drums in some well recorded country and or pop song.
This is why I am somewhat satisfied with my Bose QC25s. I bought these primarily for the combination of noise canceling and portability but they do have some punch to them as well. I can take these to my favorite brewery while I do some work (I am a retired accountant that has a small bookkeeping practice) and drown out the noise or use them at home in our living room while my wife watches Dr. Phil or whatever. I do understand there are better sounding headphones so this is why I am on the hunt for one or two other sets of headphones.
I also used to like classical music, and I say used to because my listening experience depends on the sounds of the strings and quality of the recording. I don't think the Bose do classical very well. I never will forget the one time when I had a tube amp and how sweet it made the strings sound.
So I am thinking I may need two sets of headphones to really enjoy the wide variety of music I like, but would love to find just one. I use my laptop (Yoga Pro 2) for much of my music so I would appreciate your suggestions, even if it is for more than one headphone, and what kind of amp/dac should be paired with them. I really would like a wider soundstage where I feel the musicians are in front of me instead of around me without sacrificing bass punch and accuracy. I would like to keep the cost around $700 to $800 and that would be for one headphone and amplifier with the intent of maybe getting another set if needed. I am also a photographer and would use more than one camera because not one camera would be best for every situation and I am beginning to think the same could be true for headphones. I am very new to this forum and hope there is a pm feature, feel free to pm me with your recommendation. I will do some research on the products you did mention.
Ah the hd 650 there are tons of people that love this headphone and when I purchased it myself I realized it was the most boring headphone I have ever purchased. It makes music sound almost unexciting its true that the detail is there and such but ugh it just takes takes the life away from everything, some of the reviewers put it best here when they say its a headphone you can fall asleep with.
the guy i bot the headfone from...for usd250...has long hair covering the ears...wears the can over that mop...puts the vol to low...n zzz type of guy. 
My OTL amp seems to give this hd650 some thummmp...
wasnt great with the BCL, not sure about the vioelectric, maybe along the same vein..? 
Anyway, there are always other cans to LOVE...
just move on to the next GREAT can...a DT150 maybe? 
@ Gary - Thanks man, I'll hit you up with a PM and see if I can help.
@ Spiderman - Yeah I don't listen to music to fall asleep. That's what books are for. 
@ Lorspeaker - Yeah I'm not hating on it, I think it's a decent headphone and completely agree that it may not pair well with the Violectric, but that in and of itself means the HD650 is picky and not very consumer friendly. I wanted to offer a consumer opinion to head-fiers to help inform future purchases. I think some of the ink that has been spilled over the 650 is misleading... But yeah, not hung up on it. I've gone upstream and got a HD800, LCD2 and Oppo PM1 so it's not like I've written off Sennheiser. 
People misconstrue it being called a so-called boring headphone, or one that puts you to sleep as meaning the headphone is undesireable .
It just means it's not going to offend you and may be relaxing to listen to. For people new to the hobby, those are realistic goals to start with.

I think it helped Sennheiser's longevity to release a more ambitious statement product, but as a brand they became my first recommendation for friends after hearing the HD650, HD25-1, HD280.
I still haven't heard the HD600, but that seems like the most often recommended headphone of any headphone available.

The HD800 seems to improve upon the HD650 in almost every way.
In fact the HD800 sounds like the 100 000 watt speaker set up I mentioned earlier when played at moderately loud volumes.
But the HD800 can maintain that same high level of detail at low volumes better than the HD650, which has to do with measured distortion. 

@Lorspeaker you might want to try a headphone with low measured distortion, if you're looking for a GREAT can.
I had to join this site to compliment you on your excellent review. I appreciate that you said what everybody else may have been thinking but didn't have the guts to say. I guess it is pretty fair to say that these headphones weren't fit for your purpose. You were very concise about your equipment and did a great job of explaining where you were coming from. I wish more reviews were like this. I have a pair of 702s and although they are great headphones I thought the 650s might be a nice headphone to own as I too read about the bass "impact".  I suppose the 650s are designed to be a bit more refined to compliment certain kinds of music, and they just don't "rock". There is nothing wrong with that and this review has been extremely helpful for someone like me because I don't think I need another "refined" headphone. I have read so many reviews describing the "veiled" sound of these headphones but your description of the headphones character is better than any I have read. And I did not find it negative in the least, nor did it put me off the headphones. In fact it made me realise that they are probably very pleasant and non fatiguing to listen to. 
  Again I wish more reviews were like this one. It ticked all of the boxes for me. 
1. Equipment used to test with and allowed proper break in time if there is such a thing.
2. Music preferences 
3. Experience with other brands and objective strengths and weaknesses with those brands.
4. Strengths and weaknesses of product being reviewed without being overly harsh or critical.
5. Emphasises the phrase "for my taste".
6. Honesty
I don't think may people take into consideration the kind of music certain headphones are good for. We all assume we want the best quality with the most accuracy but sometimes going into the higher end can reveal too much and make the music not fun to listen to. And as this reviewer has rightly pointed out the bass spectrum of the music is a big part of the enjoyment of music for many, regardless of musical preference. Judging from the juvenile name calling from that Herb guy this point has hit home. Sometimes a less "refined"  setup sounds better as it works more efficiently on more systems or it just gives you a good thump in the low end. I feel that informed reviews like this one keep people from making costly mistakes.  Thanks again 
I would like to add my 5 cents.
I agree with you that the build quality isn't the best and that in this price range should be more metal, as far as the look goes well that's up to personal opinion. For comfort the velour on these is beautiful and I wouldn't replace it with anything. These headphones are VERY tight when you first get them. Given a couple weeks of taken them on and off they become just right. Honestly pardon the cliche but I feel like I was born with these on as the snugness and velour just makes it feel like they are part of my head. I replaced the stock cable with a cardas cable which is a pricey upgrade and as far of a difference as it makes I'm not sure it's totally worth it. The build quality of the cable is much better than the stock cable but I don't think that using the stock cable will decrease the enjoyment or sound quality of the headphones. As far as the amp goes. I use an entry level amp with them but have experimented with higher end amps and honestly I don't hear much difference in the sound quality except for how far you crank it up to get the same volume. As for a DAC I have found that in order for a DAC to make a noticeable difference with these it needs to be a higher end DAC as most entry level DACs don't do much to the sound quality as opposed to just listening straight through an amp. Like the cardas cable a DAC is a personal preference.
On to the actual headphones. These headphones are a masterpiece. Never have I ever heard music more naturally then through these. No constraints whatsoever, no echoing, just pure, natural music the way it was meant to be heard. It sounds like someone is singing directly into your ear, so pure. I personally can't imagine anyone not being swooned by these headphones but oh well. For people calling these dated I find that so funny, seeing as these are slightly over 10 years old what exactly would you call Koss products? Ancient? Dinosaur? These headphones are itmeless.
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