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Sennheiser HD 650 Headphones

  1. Willy 2 Streams
    The 'tube amp' of the headphone world....
    Written by Willy 2 Streams
    Published Nov 28, 2014
    Pros - Smooth, lush articulate mids. Deep, tuneful, powerful bass. An organic, 'all of one piece' sound.
    Cons - Air...give me AIR!
      Wow...these cans seem to generate a lot of passion! Mr. Tech Agent's review below is a pretty tough act to follow, but I will try. 1st a quote from the literature that comes with the HD 650's: "With the HD 650, Sennheiser has followed the changes in the listening habits of music lovers and the way in which they experience sound. In spite of all purism and the highest demands on precise sound reproduction, a slight change in listening behavior is detectable. Today many music lovers want to feel the sound more instead of plainly analysing it. The HD 650 now captivates your senses where you used to be a mere observer. It allows total submersion into an ocean of music and lets you completely forget your surroundings..."
         So there you have it! They are clearly telling you that they are tailoring the sound of these cans to what they think audiophiles want to hear. Maybe, with all the bright, over equalized recordings out there, you might not WANT a pair of 'ruthlessly revealing' headphones. You MIGHT just want a pair of cans that can make almost ANY recording sound like MUSIC that you want to listen to. If so, and especially if your signal chain is all solid state and digital, that tends to head in the same 'relentless' direction, than these are your cans! I'm thinking that's what Sennheiser was thinking, when they designed these headphones. In a word, they put a slight mid bass hump in these, they gave them silkier sounding mids, and they rolled off and smoothed out the treble, compared to the 580's.
         I've had a pair of HD 580's for 20 years. I was thinking of replacing them with a pair of HD 600's, but I felt that might be too close to what I already had. After all, the 600's have the exact same drivers; the only difference being the carbon fiber along the earcups. So I bid on a mint pair of 650's on Ebay, and won them. $275.00 delivered. When I first connected them to my Schiit Valhalla (a SUPERB match BTW...these 2 were literally made for each other!) my 1st thought was "Are they SUPPOSED to be THIS DARK?" Actually, my very first hit was how velvety smooth the mids were-better even than my 580's, but clearly cut from the same bolt of cloth. I was at this point listening to vinyl, via my tubed Quicksilver pre amp. So I switched to CD. My goof...the signal just wasn't quite as high voltage as off the CD outputs. Once I corrected for that, they sounded pretty equivalent... But, a word to the wise...you CAN go TOO far to the Dark Side with these, if your front end  is already that way.  So then I started swapping the 580's and the 650's back and forth while the CD was playing. The 580's actually seem to be more 'ruler flat' sounding. No slight mid bass rise, and the treble was more extended. But the treble was definitely grainier than the 650's, and seemed a bit disconnected from the rest of the frequency spectrum.The 650's made the 580's actually sound more analytical. I would not have called the 580's 'analytical sounding' before I heard the 650's, but compared to them, they are. That's that 'organic, all of one piece' sound. And that, I submit, is the magic of the 650's. There is something about them that makes you just want to listen to music...for HOURS! And like the 580's, they are comfortable enough that you can do so. So, I think that's who these cans were designed for: people who already have a good sound system, and want a nice sounding pair of cans that matches the overall sound quality of their big rig, but they don't want or need to spend thousands on an all-out set of ortho headphones and amplifier. If I were an audio engineer mastering a recording, I probably would not choose these cans to work with. I'd probably go with the 600's. And if I were a DJ, these could not be a good choice due to their lack of sound isolation. And for portable, they are not the best due to their 300 ohm impedance. These cans are clearly designed to work with a dedicated headphone amp (again, the Valhalla is a stupendously good match for these cans, for the money!) as part of a dedicated high end system. For that application, these are primo. Not for everyone; some people like a brighter sound. But if you want a comfortable pair of cans that just makes the music sound RIGHT, that you can listen to for HOURS without any fatigue, give these a try. As I continue to listen they're sounding closer and closer to the frequency balance of my 'big rig'. I'm not sure if it's because they are still breaking in (being used, I'd assumed they already were), or it's my ears that are adapting. Either way, these are 'good enough' for me, in the application I'm using them for. These things have finesse, but will go stupid-loud without any hint of break up...and that's another thing they do better than my 580's. When the orchestra goes "baum BAUM!!" the 580's get a little congested. The 650's don't. Like I said, you can play these things crazy-loud with no hint of congestion or break up.
         In summary, this is a good design, that has passed the test of time. While these don't have the gorgeous transparency of the best ortho or electrostatic headphones, they have the best bass and midrange of any dynamic cans I've ever heard. If your front end is a bit bright, or your current cans give you listener fatigue, definitely give these headphones a try!
      Pokemonn likes this.
    1. cs098
      have you tried removing the foam? That might brighten the sound a bit. Made it more balanced for me.
      As nice as the 650 sounds, sometime I miss the sparkle other cans have.
      cs098, Nov 28, 2014
    2. Willy 2 Streams
      A foamectomy will definitely be in order, soon as I can remember to get to the store to get a pair of black panty hose...I'm going to do the stocking mod.
      Willy 2 Streams, Dec 24, 2014
    3. Willy 2 Streams
      The foamecty with the black nylon stocking mesh as substitute....a definitely worthwhile tweek that will set you back all of two bucks! More air, treble slightly more extended. Plus the drivers show thru the mesh, and make the cans look cooler. 
      Willy 2 Streams, Jan 6, 2015
  2. MrTechAgent
    Klassische Kopfhörer !
    Written by MrTechAgent
    Published Aug 13, 2014
    Pros - Sensational Excursion Factor , Exquisite Bass Extension , Almost perfect Mid-Range , Classic HE-60/90 Design , Potential Upper Treble Extension
    Cons - Spare Part Cost , Grainy Compared To Beyers and E-Stats, Could Be More Distant
    The one who started it all, the 650s was a unexpected purchase for me, I was 16 back then when I got the 650s , the only nice headphone I had was the v6 and a cheap Supra Sony but since I was building a nice PC at the time, I decided to invest in some Audio , wanted to get the best ....Initially I was gonna get the hd800, the price wasn't a issue since I had a huge budget but I decided to invest that elsewhere and got the 650s instead, these in one word are my "Favourite" Headphone, love them.
    To the sound , I always thought the 650s were a acquired taste until I got AKGs, little did I know what I had there
    The 650s signature is warm, rolled of yet detailed with a amazing bass extension, as far as dynamics go the only headphone I enjoyed the bass on was the Tesla 1, no other headphone has the 650 bass , control is just exceptional , I have test tones which determine the tightness and the 650s are off the charts , no headphone has performed like them , they also have a great excursion factor ...what that means is that they will never rattle, the membrane will never be over-driven, usually a lot of people call it SPL but not all high SPL headphones have a good excursion factor, usually excursion factor affects low frequencies, Output Impedance can minimize it but not eliminate it, more the control less the rattle but the 650s are extremely robust, these will never fail ...just sensational  
    Let's descend this time - 
    Treble - There is no doubt they are rolled off but ...I have heard the 650s on systems where the treble was right there, with all the detail and presence, would I call them veiled or muddy ...absolutely fuc**** not , they have all the detail, but this roll off can be good for some people who like a relaxed sound, they are just luscious and full bodied , they are never thin . As much as I love the treble they aren't grain-free when compared to Ultra-high end headphones, do I care, again absolutely  fuc**** not, musicality wins. 
    Mids - If you are considering buying these, I don't need to tell you about the 6XX mids, imagine a sound which encompasses you in it , that's what the 650s do when it comes to the Mid-Range , they have one of the best Mids I have heard, to this date I have to find a dynamic headphone which has the musicality in the Mid-Range like the 650s do, if you know a dynamic headphone which has what I'm looking for, let me know down in the comments. 
    Bass - The bass man ...I love the bass on these, the extension, tightness and overall sense of impact is top notch, as I said earlier the only dynamic headphone which impressed in the bass was the T1, now of course I know a Planar will kill it when it comes to sub-bass, that metal never rolls off, goes to down 20Hz with a flat line, but these are not a Planar so for a dynamic they are my top headphone, nothing touches the 650's extension and refinement. 
    Build and Comfort - 
    I think they are well put together, Senn is the Samsung of Headphones..all plastic of course.
    But as I said they are well put together and have the solidity I could expect from a decent headphone. The Headband is plastic with two spring steel rails attaching to the ends.
    They can easily be bended to make them clamp less if they bother you initially, I never found the clamp bothersome..at any rate natural break-in is the best of course, my two year old 650 compared to my brand new 600 have a significant difference.
    The Earpads are generously padded and are very comfortable, the 650 happens to be my top headphone for comfort, which is a goof thing of course.   
    Yes of course there are some negative things - 
    1) The dt880 is more refined in the treble, is much less grainy but again it doesn't have the other tonality edge and the excursion factor is not even close to the 650s. 
    2) The Soundstage is not that impressive, a lot of people use the classic term "3-Blob" I still don't know what that exactly means but hey ....The dt880-990 surpass the Senn in terms of Soundstage. 
    3) I wish the Spares weren't so expensive, for a earpad I could buy a entire headphone like a NVX XPT100 , not cool Senn !!!!!
    Some Random Notes - 
    1) Although these are 300Ohms I find them to be fairly easy to drive.
    2) The Stock cable can be easily made balanced.  
    3) I would recommend a nice OTL, I am using the Valhalla 2, in a perfect world I could choose SS, like a Violectric Stack or maybe a HDVD-800 but since it's not a perfect world I have to resort to Mid-Fi/HiFi amps which are fine, they still portray the emotion. 
    I will add more..this is all I can think of right now :p 
    So yeah, love them to death 
    I don't think my opinions will change until I get a 007 from STAX, till then I will enjoy the mids on my 650s 
    The comfort is excellent and so is everything else , if you want some of the best dynamics in the world get the 650s , they will surely make you smile , it doesn't matter if you have the best of the best setup, if it doesn't make you smile, it's a waste of money, take this analogy .....Upgrading a BMW 328i (F30) to make it faster than a RS5 is more fun than getting a RS5 , of course a RS5 is a RS5 but it will not make you smile as much as a upgraded F30 will, that's what the 650 is for me .....a must have headphone, take it easy folks, my Video Review will come in 2 days. 
    Video Review - 
      Essence STX, bpandbass, zanox and 5 others like this.
    1. View previous replies...
    2. AtrafCreez
      Thanks a lot !
      AtrafCreez, Sep 28, 2014
    3. Sennyboy
      Hello sir, thank you for the review.
      I see you mentioned them as grainy, I find them to be offensive and harsh, so is that grain or something else?
      Sennyboy, Mar 16, 2015
    4. huberd
      Compared to the HD-700 they sound distorted and have no treble air or sound stage. I think this is what a lot of people like about this headphone. 
      huberd, Feb 18, 2016
  3. homeros8000
    A Review For Classical Music Listeners
    Written by homeros8000
    Published Feb 24, 2014
    Pros - Tonality, Easier to match with other equipments, smooth sounding, beautiful mids
    Cons - For some recordings and with some equipment it can sound bass heavy or too dark, narrow soundstage, colored treble
    My reference for reviewing the HD 650 is the AKG K701. I've used the HD650 with various amps and sources including the Nuforce HDP, Headroom Ultra Micro Amp (now discontinued), the Beta 22 (2 channels), Musical Fidelity M1 and the ALO Rex MKII. Sources included Marantz CD5003, Ultra Micro DAC (discontinued), Ultra Desktop DAC (discontinued) Nuforce HDP and Centrance DACPort LX.
    I think many reviewers have already talked a great deal about the characteristics of the HD650. Most of them have better experience and probably are more capable of discerning the pros and  cons. I only wanted to add a few points regarding classical music listening.
    Some listeners shy away from the HD650 when listening to classical for their dark sound and lack of airiness but for my ears they are suitable for the genre. First of all they have a beautiful natural tone for strings and winds, in comparison to the K701 which has an anemic neutral to bright tonality. The HD600 has a similar tonality to the HD650 but IMO the latter is more refined, less grainy and enjoys a better sound stage and imaging. The only drawback is the HD650 need for a neutral to bright system to sound their best. With some set ups it can sound too dark and dull. I heard them at their best with the Beta 22: a very big and tall soundstage with exceptional depth and detail. 
    When listening to orchestral music on the HD 650 there is more weight and impact. The experience is closer to live performances in comparison to K701. There is also more emotional involvement, using the K701 is like reading the notes, while both HD600 and 650 reveal the mood and the feelings of the piece. In other words, listening to the HD 650 is like being in the concert hall, while the K701 experience is closer to being in the studio. 
    The HD650 is more forgiving with older recordings. Classical gems like Arrau's recordings of Beethoven's piano sonatas or Oistrakh glorious recordings of Prokofiev and Shostakovitch can't be rendered with revealing headphones like the K701 or the HD800.
    It's also much easier to match the HD650 with the right DAC and AMP in comparison to the K701. Actually the HD650 is an excellent performer with high grade equipment and a steal at its current price (around $300 used). For the K701 it's very hard to find the right amp to pair with it, it sounded at their best on the Luxman and MF M1 HPA amps. 
    The K701 is definitely more airy, with a wider sound stage, but the warm tone of the HD650 provide a solid placement of instruments in space. Sometimes I feel the K701 too thin sounding for complex passages compared to the HD650. 
    This review was done on mid fi gear involving Cetrance Dacport Lx and ALO RxII. 
    Update 03/28/14
    I did an extensive comparison on the current set up: Flac and Aiff files played by Audirvana plus on a Macbook computer. The macbook is connected by optical cable to Headroom Ultra Desktop DAC. The UDAC is connected to Musical Fidelity M1 headphone amplifier via DiMarzio RCA cables. 
    On this set up the AKG Q701 is performing very well indeed. The highs are smoother and the sound is more open, with fuller, richer and clearer mids. The imaging and the depth of the soundstage have been immensely improved. In short I feel that the Q701 and the MF M1 amp are very good combo, much better than the HD650 combined with the same amp. Probably the M1 being slightly warmish works better with brighter headphones like the Q701 and the HD800. 
    The HD650 is certainly more fun to listen to, but the Q701 is more detailed with a wider and bigger sound stage, better imaging and more extended treble. But the tonality of the HD650 is more true to life, where K701 sounds pale in comparison. When listening to the HD650 you feel like living inside the music, while the Q701 is more objective and cold. The mid on the HD650 is rich and has a palpable presence, compared to the thinner mid on the Q701.
    Of course these observations are purely subjective, and based on my experiences with different set ups. 
      dunhill and SunTanScanMan like this.
    1. View previous replies...
    2. spiderking31
      I have demoed the sennheiser hd800 on a McIntosh MHA100 AMP/DAC combo, and compared it with my sennheiser hd650's, and I'm not going to kid anyone here. The hd650 is superb on that rig! Yes, hd800 is better...that much better? I don't think so. It's something called "diminishing returns". Look up that meaning on Google. The hd650's are a VERY SUPERB headphone. I know because I own the hd650 and use it on a very Niiice rig. Don't fool yourselves. $1500? They're not worth that much. The hd650 to me, is under priced...IMHO...hope this helps everyone before you drop $1500 bucks
      spiderking31, Nov 24, 2014
    3. Willy 2 Streams
      Very good description of the 650's sound, thanks! I do feel that my 650's darkish quality sometimes muddies things a bit in the upper bass/lower mid range with SOME classical, compared to my trusty 580's. My 650's are still a work in progress, will report back after swapping out the cables for some silver plate copper aftermarket ones. In stock form, I'm thinking these things need more air, as I said in my review.
      Willy 2 Streams, Dec 11, 2014
    4. Quinto
      great review,  I'll be getting my HD650 soon and will be listening mainly classical (lots of solo piano) and some jazz, cheers!
      Quinto, Nov 28, 2015
  4. IPoopFrootLoops
    You can't go wrong with this timeless classic
    Written by IPoopFrootLoops
    Published Jan 14, 2014
    Pros - Smooth, sweet, loving sound. Comfortable.
    Cons - Nothing to me
    I am by no means experienced in this field. I am a poor 18 year old who spent a lot of time dishwashing in order to support his unreasonable obsession with great sound.
    When searching for my perfect headphone, I narrowed down my choices to two headphones: The Sennheiser HD650 and the HifiMan He-400. I originally picked up the HifiMan He-400s and spent a month with them before parting. They sounded great and were built like a tank, but I knew that the ortho sound wasn't for me. The sound was too fatiguing, and this was exaggerated by the poor comfort that they provided.
    My next step, obviously, was to pick up the Sennheisers. As soon as i put them on my head, i knew these were right for me. Comfort was above (my admittedly high) expectations. I could sleep with these babys on, and the sound exceeds their comfort. The smooth, romantic sound woes me in every time. These are the cans that you could listen to for days. 
    The Sennheisers gave me what I ultimately wanted. And that was to have sonic nirvana poured into my ears for hours on end. I can slip these on and do my homework without being interrupted or l can critically listen to some vinyl.
      TwoEars, SaLX, Pokemonn and 2 others like this.
    1. View previous replies...
    2. Juandv9307
      try a cheap aune t1, they sound really good togheter.
      Juandv9307, Apr 18, 2014
    3. TwoEars
      You have chosen... wisely...
      (Bonus points for knowing the movie without googling it! :wink:
      TwoEars, Nov 7, 2015
    4. Linn9000
      Orthos fatiguing? what crazy talk is this...
      Linn9000, Sep 11, 2016
  5. irie
    Great Sounding Headphone
    Written by irie
    Published Jan 7, 2014
    Pros - Good SQ, soundstage, mid bass, comfort
    Cons - lacks sub bass
    one of the best sounding headphone.
  6. DrumminD21311
    New Experience Right Out the Box
    Written by DrumminD21311
    Published Dec 3, 2013
    Pros - Extreme clarity, very comfortable
    Cons - Style, Dark
    I'm a noob to high quality audio equipment. I have been using V-Moda M-80's. I bought these because they were onsale for $272, and it would be stupid not to buy them at that price. I just opened these up and put them on. I understand that these may need to be broken in first. One of the biggest positives I noticed right off was the level of comfort. These are extremely comfortable, like I have pillows on my ears. The quality of the vocals is outstanding. The music is so much more crisp. Now to the negatives. Compared to the M-80's the sound is so much darker and subdued. The sound from the M-80's is bright and loud. No amp is needed and the M-80's can easily damage your hearing. With these, the music seems to be playing in the background. That's the only way I can explain it, like I'm listening to a recording of a recording. Maybe someone can explain this to me, and what I need to do. These also don't play very loud. I assume I will need to buy a dedicated amp to power these.
    1. View previous replies...
    2. eugenius
      If you want a solid state reference amplifier, the Lehmann Black Cube Linear is what you need for the HD650.
      eugenius, Dec 5, 2013
    3. eugenius
      If you want a solid state reference amplifier, the Lehmann Black Cube Linear is what you need for the HD650. It "wakes it up" and puts some energy into the HD650.
      eugenius, Dec 5, 2013
    4. spiderking31
      Try the little dot Mk3 tube amp. These are 300 ohm, and need plenty of power! That's why they sounded so laid back. They were under powered...just so your aware
      spiderking31, Nov 24, 2014
  7. mcandmar
    An all time classic
    Written by mcandmar
    Published Oct 5, 2013
    Pros - Comfort
    Cons - Fussy about Amps
    The headphone i compare all others to, my reference point, my grounding. Wearing the HD650's is like coming home from a trip, wrapping yourself in your dressing gown and curling up on the sofa in front of the fire. Warm and cosy, and there really is no place like home.
    1. LoveKnight
      What a concise and wonderful review, sir. I like it.
      LoveKnight, Oct 5, 2013
  8. gabsonuro
    an excellent sounding headphone
    Written by gabsonuro
    Published Sep 27, 2013
    Pros - -rich, creamy bass -extremely comfortable -not harsh on the high end -excellent vocals -extremely large soundstage
    Cons - -headphone can clamp a little hard when you first get it -can take up to 200 hours to burn in completely -earpads are a little hard when new
    An excellent sounding headphone for the price. The 650 is what separates a mid-fi headphone and a hi-fi headphone. It is has extremely rich bass and excellent mids. The headphone does require a little amplification, but it is not too difficult to drive. The headphone is extremely comfortable- when broken in. when you first get the headphone, it clamps a little hard and the earpads aren't very soft, but both loosen over time. Some people may not like the "dark" or more warm sound, in which case they go for the hd 600, but if you do like the warm but not overly warm sound this is a extremely good headphone. It sounds excellent for classical/jazz, acoustic, rock, and metal. The bass is creamy yet slightly punchy, the highs aren't piercing but aren't laid back. The soundstage and natural reverb the headphone adds is sublime. Once the headphone pads wear in the comfort is unrivalled. 
    1. thatBeatsguy
      "...the comfort is unrivaled."
      ...No, it's not. The Beyers' velour pads are world-renowned for their comfort. Still, an HD600 is still comfortable.
      thatBeatsguy, Sep 28, 2013
    2. gabsonuro
      i changed from dt 880 and the dt 880 does not compare to hd 650 comfort
      gabsonuro, Sep 28, 2013
    3. i019791
      If hd650 has "extremely large soundstage" (comparing to which peers ?), how do we characterize the soundstage of akg k701 ?
      i019791, Sep 28, 2013
  9. gevorg
    True high-end headphones
    Written by gevorg
    Published Sep 22, 2013
    Pros - great soundstage, very comfortable
    Cons - can sound "dull" without good amping; not revealing as some competitors
    The HD650s have been out for many years already and became a reference point to compare with other headphones. Although not the best headphones, they can still introduce you to the world of high-end sound, as long you provide them with proper amping.
  10. Pepper
    Truly a "laid back" sound. Charming, but not spectacular. (HD650 with Bottlehead Crack + Speedball)
    Written by Pepper
    Published Sep 9, 2013
    Pros - Comfortable, never fatiguing, and with the right recordings the lows can really shine
    Cons - Treble a little too slow, bass could be a smidgen punchier
    I moved from IEMs to full sized headphones, and the HD650s were my first real investment. My first "real" audiophile big can was actually the Audeze LCD-2s, but I never had proper amplification back then. As a result, I never experienced what the LCD-2s could actually deliver. I ended up selling my LCD-2s and then going back to IEMs, all the way until this year when I took the dive and tried to buy the safest, most solid cans set I could. I went for the most famous, solid buy and went hunting for the best amplifier match. This, of course, led me to the Sennheiser HD650s.
    My chain ended up looking like this:
    Foobar2000 with WASAPI Event, FLACs > Schiit Modi DAC > Bottlehead Crack + Speedball Upgrade (with Tung Sol 5998 Tube) > Sennheiser HD650s (Silver driver)
    I have been beating myself up over whether to rate the HD650s with 3.5 stars or with 4. If I really could choose, it would be a 3.75/5. However, I am marking in a very difficult manner; I have tried out a handful of good headphones and so it would take a lot really wow me. A 4-star rating would be a "wow" but with a few reservations here and there. So, a 3.75 is a very good mark; it is just short of a "wow." The details with the little green bars are a little more informative of the way I feel about the HD650s (EDIT, the green bars seem to be very inaccurate when I save the post. Instead, here are the scores: Audio Quality (B+), Comfort (A), Design (B-), Value (A+).) With that in mind, let me expand on my experience with the HD650s.
    At first, I thought the HD650s were absolutely dreadful. The bass was extremely floppy and bloated. The lows were absolutely non-existent. Treble and highs were slightly tinny, but mostly just very unrealistic and slower than a snail (it seemed like there was long decay on treble and highs). I was very concerned and posted in the HD650 appreciation thread with my impressions; I wasn't sure if I just didn't like the sound, or if there was something wrong. And, given that the Crack is a DIY amp, I also went on the Crack forums to try and figure out if there was a serious mistake. 
    Well, there was a big mistake. The headphones and the tubes in the amplifier were not burned in. I'm a very scientifically inclined person, and so I have always been very skeptical of burn-in. But after my experience with my setup and burn-in, I am now a 100% believer. The difference was so enormous that I am not sure how anyone could deny the existence of burn-in, at least for tube amplifiers (I don't expect it to be very real when it comes to solid-states) and dynamic phones like the HD650s.
    After about 30 hours of burn-in with pink noise and various music at slightly higher than listening volume, suddenly the lows appeared. The bass tightened up tenfold, and the treble lost its sibilant ring. The mids, for the most part, sounded the same, though they were never really atrocious to begin with. 
    The design of the headphones is simple, but they look professional. The biggest problem I have with the HD650s is their construction material. I was very disappointed to find out that the headphones are made out plastic, and plastic all over. This doesn't mean that they're flimsy, but I wish there were more metal on the headphones. If you look at the picture of the HD650s on the HeadFi reviews section, they look almost metal. The reality, however, is that they're almost entirely plastic and a lot lighter than you expect. The headband comforter is also not premium; for instance, the headband on the HD598s seem higher quality.
    The clamp force on the headphones is great. It's a little strong, but it's better to be strong and loosen over time than be loose from the get-go. The earcups are quite large and will fit around even the biggest of ears. 
    My reference point has primarily been my experience with the Shure SE535s, Earsonics SM3 V1s and the Westone UM3X in-ears. In terms of speakers, a set of JBL LSR2325p studio monitors. The rest of my can experience has been with lower end headphones (like the ATH-M50s), Shure SRH750DJs and a bunch of lower end Sennheisers. Indeed, these comparisons are not always fair; each is a different class and will present sound differently. With that in mind, I will try to present my impressions as transparently as possible.
    The sound of the HD650s is really good; however, I would hesitate to call them spectacular (though they are spectacular to people who allegedly enjoy the sound signature). When people say that the HD650s are laid back and mellow, they really are not kidding. I always had a hard time imagining what they meant. The closest thing to "mellow" I could think of were the Sony MDR EX1000s, but the Sonys are more "romantic" than they are "mellow."
    What I found "laid back" and "mellow" to mean is that nothing is really forward or present with the HD650s. Some people really value this aspect of the HD650s. For me, it did not really hit the spot, but I can respect and appreciate it regardless. Nothing really stands out with the HD650s: everything sounds good, but nothing really jumps out at you as being their focus, or even as being superb. This makes for a mellow and relaxed sound. You will never fatigue listening to the 650s because nothing is being pushed on you. With the 650s, the music is presented gently to your ears, and it makes very good for "just listening" and going about your business. It's probably the best headphones to have on while casually listening, but I believe you will be moderately disappointed if you would like to really close your eyes and feel lost in the sound or if you have high expectations about being swept off your feet. This is because with the way the HD650s present the music, you just know that the music is being played at you and that you're listening through a pair of headphones (albeit a really good pair).
    The bass is very, very good. I just wish it could be 10% punchier, but it does a very good job. However, the HD650 bass really depends on the track. On well mixed and mastered tracks, you will get a very nice bass. It is very controlled and, for the most part, feels "just right." It's some of the best bass you'll be getting if you're not a basshead, and if you're listening to music and don't explicitly want to be jumping around and dancing. I really, really enjoy the bass for any kind of listening except for dance music; it does its job fantastically. However, I believe if it were just 10%-15% more punchy, the HD650s would really be brought more to life. Then again, the phones are supposed(?) to be laid back. It's like being hit with a harder pillow; it's not too soft, and it's not too hard. It's controlled, disciplined and almost at the perfect line between whooshy and punchy.
    I believe the lows are the absolute best part of the HD650s. If you get a good recording, the lows are just magnificent. Bass guitar sounds just wonderful on these headphones. It sounds very, very natural and even electrifying at times. With the right racks, the lows really carry the track forward and keep you slightly bobbing your head or tapping your feet. This is really where the HD650s shine.
    I think I have to admit that I'm a little mid-obsessed. If you look at my previous IEM collection, you can tell that I bought IEMs I believed would bring me great mids. The HD650s, although it might be unfair because of how much I like mids, did mids just fairly. I mean, compared to anything else the average person has heard, they certainly are very good. But I do not think that the mids are as well refined as the lows. Keep in mind, though, that some people like the mids the way they are and don't like forward mids, so it is all up to you. That said, here are my personal thoughts on the mids.
    1. I believe the mids could be brought a little forward. Even if the headphones are not supposed to be uber mid-centric, I believe the mids are just 20-25% off the mark in terms of their closeness. Sometimes a track that is normally really engaging just isn't on the HD650s, and it's because the mids just aren't present as I believe they ought to be. (Then again, personal preference plays a big factor.)
    2. The mids could be warmed up a bit only because voices didn't seem realistic or natural. Compared to what I've heard on the SM3s and especially the Shure SE535s/530s in terms of vocals, the HD650s made vocals sound like they were just being played at me. I didn't feel like I was being sung to, which makes me very sad because I like it when Taylor Swift whispers into my ear.
    3. Some people argue that being too forward on anything isn't "natural." But I don't know what is more natural than hearing a singer as if the singer is speaking to you, given that's what it sounds like in real life (the epitome of natural). I could not feel my singer's breath, and I knew that there was a mic between me, the singer and the music. If you've ever heard the SE535s, that's how vocals ought to be done; they are so lush, smooth, caramel and real that you sometimes get goosebumps from good recordings.
    4. If you're not vocal-mid focused, then the mids will do just fine. In fact, guitar sounds great through the HD650s. B.B. King sounds great on the right recordings, as does distorted guitar in classic metal bands (e.g. Judas Priest, Iron Maiden, etc.) and groups like Paramore. However, the vocals just isn't this headphone's strength; I tried Grammy winning engineered albums and very well reputed vocal albums (including jazz vocals, etc.), and none of it stood out as being outstanding. It's just a fair contender.
    The mids, as they stand, are pretty laid back. You get fairly good detail, but there isn't a lot of body to the mids. This is perfectly fine for instrumentals, orchestras and a lot of other music, but it is not good for very vocal centric music. The 650s are still quite textured, and so the mids aren't by any means bad. Guitar, especially in classic metal and rock, sounds great. I love guitar through these headphones. However, despite what some other reviewers might say, coming from someone who has a history of hunting for mids, I do not believe the 650s hit the mark on mids if you are someone who listens to a lot of vocals. For instance, running Adele, Taylor Swift, Hayley Westenra or lower voices like John Mayer or Diana Krall(sp?) through any of the mid-kings would be a reliable hit. However, none of these really stood out with the HD650s.
    This is all to say, however, that "Kind of Blue" by Miles Davis sounds absolutely extraordinary on the HD650s. In fact, I believe it is the absolute best recording I have heard through these headphones; it has yet to be bested. The saxophone is breathtaking. But Miles Davis wasn't known for his vocals, and none of the tracks offer any. But that's why the HD650s did well with it.
    With my first Raytheon 6080 tube, there was a lack of clarity up top and in the treble in general. Switching over to the Tung Sol 5998s, the highs and treble came out. The highs are never sibilant, but aren't very energetic either. Overall, they are highly satisfactory for most purposes, but I believe things would really come alive or be taken to the next level if you could squeeze another 15-20% out of the HD650s up top. Then again, the HD650s aren't known for an energetic or hot-top end. 
    The HD650s are not very analytical, but it is enough for you to understand a bad recording for a good one. However, it is forgiving enough to keep everything tolerable, even if not blissful at all times. I don't really find myself complaining about the treble or highs, but I also don't find myself being blown away by them either. The "air" of the HD650s lends great to shimmery sounds, however; it kind of sparkles just enough for you to smile.
    The soundstage of the HD650s is all right. Some people have described the sound as "three blobbed" and I understand why that would be said about them. The HD650s sound like they have a medium-small room soundstage. The instrument placement in the recordings is good, but I sometimes crave that BIG sound. I thought the HD650s would deliver on that front, but they really aren't that big. The suondstaging is by no means bad, but again not spectacular. The sound is not congested, but you can tell that the music is being played through headphones, rather than feeling like you're there with the music.
    Instrument separation is not particularly high (but that doesn't mean the HD650s lack a lot of resolution). I think the 650s like to give one coherent, gentle sound rather than ripping everything apart like the UM3Xs or completely punching you with a tidal-beam of sound (as on the SM3s). I think the level of resolution is perfectly fine. I think it could use a nudge more just because, but there is nothing negative to be said here! But this is a good segue to the next point:
    You can nab a mint pair of HD650s on the secondary market for extremely cheap. Low to mid 300s before shipping. That is an oustanding deal for such a solid pair of headphones. I bought a winter coat more expensive than my HD650s today, which just helps put everything in perspective.
    If you noticed, most of my criticisms were wanting 10-25% more out of everything. But I suspect that's what is supposed to be delivered by the next level of headphones (HD800s, LCD2s, etc.) which cost a lot more. For the price, the HD650s are very well justified. And, the truth is, the HD650s should be a staple of every headphone collection (if you can afford to keep it)!
    Overall, a very good headphone, but seldom spectacular (except in the lows if you hit the right recording). The headphones sound laid back, and maybe that was Sennheiser's goal. But, if I dare say, perhaps it sounds laid back because it does everything just "well," but never anything more. If you took the 650s and somehow could extract that extra 10-15% from it, it would be absolutely outstanding. The phrase "So close ... yet, so far away" describes my HD650 experience quite aptly.
    The lows are its greatest strength, followed by the bass. The mids leave you wanting a lot more if you listen to vocals, but can deliver from time to time if you like guitar or non-vocal music. Dance music and electronic music, however, is really off the table. Electronic music is what I listen to the most (not anymore, though, just because of my setup!), but I just don't think electronic music fits well with the HD650s because electronic music is, by nature, a high energy genre, and the HD650s are anything but energetic. They are not energetic anywhere along their sound, and I think that is both what makes them so charming, but is at the same time their downfall.
    The HD650s, by being so close yet so far away, is just a great, solid listen. It really is the introductory audiophile can par excellence. It does everything well, but not well enough so that you know there is for sure better out there. If you could just push that extra bit of work out of it, the 650s would really be stellar. But, hey, maybe it's just my amp and DAC; perhaps you could get the extra work out of them if you hooked up some multi-grand amplifiers... Then again, if you're fooling around with something like a Zana Deux, Leben or Wine Audio, you probably shoudn't still be listening to the 650s! 
    Very good, but seemingly always a tad short of spectacular. 
    1. Mshenay
       You ought to try a Modded w1000x, it's... pretty much everything you wanted out of your HD 650 [just by reading over what your wrote] although it's rare to find a FULLY modded one for sale [New pads + purrin mod] but if you do I think you'd LOVE it
      Mshenay, Sep 9, 2013
    2. grrraymond
      Taylor Swift, lol.
      grrraymond, Sep 26, 2013