Sennheiser HD 600

Well I'm kinda new to Head-fi & since I'm a big fan of the HD600 here's my personal review of them which also touches on the amps & replacement cable (only mention it not analyze it).  Here goes :
 
What I enjoy the most out of the HD600 sound is the balance & clarity.  Right now I'm listening to Jeff Beck, "Blow by Blow" c1975 (produced by George Martin).  My sources are : TEAC PD-H600 (PD-H600 uses the Burr Brown PCM1796 D/A converter, a 192kHz/24-bit component) & Kenwood KA-8006 (70WPC) vintage integrated amplifier (1974); the HD600 replacement cable is from Headroom, Cardas Fatpipe cable for HD6XX.  
 
The sound is simply exquisite.  I was listening to the album with my HD650s previously and the difference I noticed immediately when I switched to the HD600 was the forward clarity of the cymbals & ping sound with no roll off (sibilance free) while simultaneously hearing all of the other instruments & nuances, perfectly balanced; some in the background but never overwhelmed.  My amp is set at it's most neutral possible i.e. the loudness option is never activated;  I only put the emphasis on the filters to bring out the subtleties when I'm listening at a reasonable high volume.  
 
This set up which is about all I can afford works wonders & truly makes the HD600 perform at it's peak.  They never sound coloured at any time.  As for the lack of bass or sub bass mentioned so often, let me just say that I can feel the bass in the sound as well as hear it i.e. the bass drum is felt & is always there & it's a special kind of subtleness by which I mean you can't miss it and I believe these headphones were designed this way in order to capture every sound possible without any over powering bass/sub bass or added treble/sibilance.  Again, when properly driven the bass sound/feel is unmistakably present.  It's quite ingenious when you consider it.  I own the HD800 but I seem to listen to the HD600 more often.  When I put them on after having put them aside for a while and turn the music on they never fail to bring a smile on my face & a nod because my ears & brains are saying to me  : "Ah yes, good ol' 600s, they never let me down" 

Note that the price I put is buying used from a fellow head-fi user
 
About Me:
I am an 18 year old music lover. I have gotten into music more and more in the last year, with this being my first major headphone buy. Since I was 14 I knew that music would be my thing. I have enjoyed listening to Tapes and CD's since I was very young, and over the last few years I have been growing as a music lover. My headphone collection has gone from Beats Solo hd(trash 1/5) -> Beats Studio(ok but broke 2.5/5) -> Monster DNA(alright 3/5) -> Sennheiser hd439(surprised me for the price 3.5/5) -> Sennheiser hd600(pure gold 5/5). I've heard some nice headphones besides the ones I've owned, but nothing flagship. The sennheiser hd439's made me re-listen to my entire music library, and really got me into the whole hifi thing. Me set up is rMBP->headphone or ipod nano->fiio e5->headphone. At the time of writing this I have ordered the schiit modi/vali. Also something about my music style is I like the music to sound as real as possible, with no over the top bass or treble. Most of the music I am listening to with the hd600's is stereo FLAC and ALAC with a few MP3's. I know I don't have the greatest set up, but I can still hear a huge improvement.
 
Comfort/Design:
The HD 600's have an awkward design in my opinion, and clamp hard on your head at first until you get used to them. The open design might let a lot of noise in and out, but improves sound quality over anything I've ever heard that was closed. The paint on the headband of the plastic looks very 80's and is unattractive in my opinion. Besides that there is not much to complain about the headband is comfy. These headphones are also extremely light feeling on your head. After your body adjusts to the clamping from the headphones they feel comfortable and you can wear them for hours.
 
Listening setup/test songs:
As previously stated my setup is rMBP->hd600 and iPod Nano->Fiio E5->HD600. I know I'm not getting the full potential out of the headphones but they still sound great. The albums I used for the testing were Highway 61 Revisited by Bob Dylan on a CD, Abbey Road by The Beatles on a 256kbps MP3, and finally Pet Sounds by The Beach Boys on a 96/24 FLAC.
 
Sound Quality:
No matter the quality of the recording, I can honestly say the Sennheiser hd600's greatly improved the overall sound quality of the music. While I haven't heard 192/24 music with the highest quality DAC/Amp/Headphones, I can still say with certainty the hd600's are some of the best headphones on the market and would be hard to beat with a direct connection to my computer. I will be holding on to these headphones for along time. The sound the produce is very realistic. They are a little warm sounding but defiantly not dark. While I haven't listened to much fast music (I hear they can struggle with faster music) I still would say they are detailed and clear sounding with all the music I listened to. They have a great sound stage with good separation of instruments, so that you can hear front, back, right, and left easily. The highs are not overly present but sound fantastic. The mids are my favorite part of these headphones, and really bring out the best in the music. The bass is great with out being over the top
 
Summary:
These headphones are the greatest I have ever had. They are built well, and sound amazing for listening to music. The most realistic sounds I have ever heard from music have come from these headphones. I highly recommend them over everything else in their price range ($300-$450).

I have owned my HD600 for 12-15 years now. I had to change headband and earpad de to weare after 10 years. I believe the Sennheiser HD600 is my best purchase EVER no matter what! I am extremely happy with them. They are great sounding. I truly feel they are shining with my Darkvoice 336SE amp. Great bass, openness, dynamic, instrument separation etc. They are not particular picky regarding amp og source. I love their sound. 
 
I also own Denon D500 lawton mod and Hifiman HE500. Both om which I regard inferior to the Sennheiser HD600.
 
Cant recommend them strong enough!

These were my first foray into high end, high fidelity sound. They were a true revelation. These headphones were built for my ears, laid back, rich warm mids, deep but controlled bass, the de-facto ultimate headphones of their time.
 
Treble: Laid back, airy, great sound stage, contrary to popular belief, bigger is not always better with regards to sound staging, some things weren't recorded on a giant sound stage afterall. Liquid cool and never fatiguing, the treble was far from analytical but still revealing of source quality, a transparent headphone to be sure.
 
Mids: Wow. Rich palpable midrange to die for. This is what you dream of. Perfect vocals, anyone could hear the sound of a singing voice coming from these and be instantly transported. The mids on the HD 600's are capable of amazing things on the right music with the right amp. Still punchy and musical on almost all music types. My only complaint was with symphonic music, which always felt a little strained to my ears. In the end, I loved these most with the xcan v2, perfect, perfect vocals, any singing voice shone through on that setup like the voice of angels.
 
Lows: Rich enveloping bass cradles the music in a seamless landscape of liquid sound. Can be boomy on some tracks. Not the best headphones for rap or other excessively bass heavy music.
 
Very comfortable.
 
High build quality.
 
An excellent headphone which with the proper amplification (tubes) has a unique sonic signature, that if it works for you, is nearly impossible to beat at any price.

I'll make this really short (because of my poor writhing skills)
 
Bass - bass is good but I find sub-bass a bit lacking. 9.5/10
 
MIDS - Wow, incredible mids. But sometimes it feels that there is to much of mids. 11/10
 
Highs - really smooth and detailed and not as harsh as other headphones like DT990 or DT880. 10/10
 
Sound-stage - I find sound-stage to be lacking and probably not as quick as I expected when I first bought them. 8/10
 
Comfort - really great comfort, no issues except for the adjustment part. 9.5/10
 
Overall: I find these headphones to be amazing, but they are quite picky, and I find it hard to listen to mp3s.

If this is your first foray into high-end audio, you're listening at home, and you can afford a decent amplifier, buy these cans before you splurge for any others.

Let me first attempt to burnish my credibility. I've had my HD600s for a few weeks. I'm not Steve Guttenberg and I haven't heard every system on earth. I have installed a number of 4-figure 7.1 systems, designed and installed my own room correction, and annoyed the Magnolia people at Best Buy by spending way too long running my own demo material through 5-figure Martin Logan electrostats. Also, I didn't spend my youth at KISS concerts, so at least for now, I'm not deaf.

Some cans I've owned or still own:

Grado SR80 (open, dynamic, $100)
Sony MDR-7506 (closed, dynamic, $100)
Oppo PM3 (closed, orthodynamic, $400)
Hifiman 400i (open, orthodynamic, $500)

I compared all of them back to back with these HD600s for many hours through a huge variety of well-recorded material, in all cases with an O2/ODAC. This latter component has ruler-flat response and zero audible distortion; I'm not messing with the output with anything that might favor one can at the expense of another.

My short take is this: start with these HD600s. Mixing, pleasure listening, whatever; if your environment allows for open cans, start here. Nothing cheaper is a more complete product in aggregate. You can spend more and get improvements in some areas, but almost always with commensurate disadvantages elsewhere. Plenty of folks with $1500 HD800s keep their HD600s anyway for when they get tired of the pointed treble of that otherwise stellar can. Orthodynamics and electrostats will top them in the midrange and highs, but often lose on bass impact.

Start with the HD600 so you can find out what you like. Because it's been around for 20 years as an audiophile benchmark that everyone's heard, you can find endless measurements and comparisons. A sentence that starts with, "I like my HD600 except for ..." is likely to bear more fruit than any other reference.

That in mind, let's talk about how they're designed and how they compare with the others above.
 
OPEN VS. CLOSED:

Headphones are just small speakers. With any speaker, you only want to hear one side. The other side makes the same noise at the same volume, but reversed in phase. If you could magically direct both sides at each other, they'd cancel out. (This is incidentally why it's important not to wire a channel backwards in your home stereo. Weird frequency nulls ensue.) We therefore need to do something with the reversed signal so it won't pollute the primary.

Closed cans (and conventional box speakers) cover the back of the driver with baffling material to absorb the sound energy. While this approach doesn't want for accuracy or frequency response, it does tend to make the listening space sound smaller. Open headphones (and "infinite baffle" speakers) solve the baffling problem by not solving it; they just vent the back of the speaker into a huge space. Great for acoustics (no need to account for backpressure and the like), but at the cost of treating the missionary one seat over to your collection of Eazy-E.

Sennheiser assumes you're listening at home with this can, so they've opted for an open design.

SOUND AND COMFORT:

Comfort is excellent. I have a big head and big ears. There's a lot of compression and I had to stretch the band a bit. After that, the light weight and plush cups that actually fit around my ears were easy to forget. The SR-80 are on-ear and uncomfortable, the PM3 are on-ear (for me) and very uncomfortable, the 7506 are on-ear and equally comfortable (because they have no clamping pressure), and the 400i are over-ear and equally comfortable.

Treble is very good. Clean, not strident, and neutral or very slightly forward. On par or better than the 400i for most material. The PM3 is noticeably recessed, but otherwise excellent. The 7506 has a somewhat forward mix with at least one frequency peak that can make it sound thin. The SR80 is quite sharp and tiring with trumpets, violins, and so on. This same treble overemphasis can add life to otherwise dull recordings.

Midrange is excellent. The 7506 sounds fairly good, but a bit "fake" and radio-ish back-to-back with the others. The SR80 has a large emphasis here suited to solo vocals, but becomes fatiguing quickly on any recording with more than a few things going on, particularly modern rock or pop. The 400i is stellar. The PM3 is almost as stellar, though ever-so-slightly colored. The HD600 has a very subtle, pleasing coloration I didn't catch until I equalized it. Detail resolution is slightly behind the orthos.

Bass is excellent. Both orthos play a little deeper and with better definition, but lack the HD600's "punch." The 7506 is decent here. The SR-80 might as well not have bass at all. There's a definite argument for the PM3; I might even prefer that one because, like all good orthos and unlike conventional dynamics, there's less distortion at low frequencies. Very pure, distinct tones.

My best description of the HD600 is "euphonic." There's nothing wrong with the sound. It doesn't sparkle or pound, or whatever wine-review description accompanies cans that try too hard. It's the kind of sound that makes you wonder where the last three hours went.

FILES AND DACS:

You can't talk about an output device without a parallel discussion about the signal chain. That includes your audio file, a DAC, and an amp.

The importance of file format is overrated. No one's ever been able to reliably tell the difference between 44 KHz / 16-bit CD "Redbook" audio and any ostensibly better (e.g., SACD, DVD-A) digital format. Surround sound and the limited dynamic range of analog records might be pleasing to some folks, but for pure 2-channel listening, there's no point chasing anything better than a CD .

In fact, even lossy compression may suffice. Much of the vitriol directed at lossy file formats stems from bad encoders. If you converted your CDs to MP3 at low bitrates with whatever terrible encoder we had fifteen years ago, you'll probably catch some noises you won't like in some material (e.g., a subtle warble in the ring of a cymbal). But modern 256 Kb/s AAC (Apple's preferred format) or 320 Kb/s MP3 encoded in the last five years? The confluence of factors necessary to be able to distinguish it from the original source (trained listener, good hearing, great gear, isolated sound, repeated listening, looking for that specific flaw) is so rare as to be irrelevant.

DACs (digital to analog converters) take your MP3, FLAC, MP4, or whatever digital signal and convert it to an analog signal that can be amplified. They're not that complicated; this conversion is very much a solved problem. Or would be if not for the lack of a line-out to skip the amplifier stage in most audio devices, or the tendency to bury the poor DAC among other noisy components that pollute the sound (read: every motherboard ever). If you decide you want a separate one, anything actually labeled as a DAC (ODAC, Modi, whatever) is fine. I spent a lot on an ODAC because it measures well enough never to need upgrading, but honestly, you could replace it with a $30 Fiio DAC and I might not notice.
 
AMPS:

Amps have one primary purpose: make the cans play loud enough. Your laptop, phone, iPod, and sound card all have amps already. Whether any particular amp/headphone combination plays loud depends on the sensitivity (dB/mW) of the headphones, their "ohm" rating (their input impedance; the electric equivalent of backpressure), and how much power the amp can output at that ohm rating. Cans with low impedance (e.g., 20-30 ohms) and high sensitivity (100+ dB/mW) are easy to drive. You could run them to deafening volumes off an iPod. Higher impedance cans, not so much. These HD600s have high impedance (300+ ohms) and middling sensitivity. They need more power. They need an external amp, whether portable and battery-powered or a metal box at home.

Just for kicks, let's do some math to prove the point. Loudness is all about decibels. Deafening is 120 dB, loud is 90 dB, and libraries are 40 dB. On this scale, things sound twice as loud every +10 dB, but every +3 dB needs double the power. You probably want to be able to hit at least 110 dB for transients. Maybe 115 dB if you don't like your spouse and want to never hear them again.

The iPhone 6 has pretty typical power output for a portable:

Driving 15 ohms: 45 mW
Driving 30 ohms: 25 mW
Driving 300 ohms: 3 mW

The scale is linear: double the ohm load and you (in physics land with spherical cows and amps that don't run out of current or voltage) cut the output wattage in half. These HD600s are 300ish ohms with sensitivity around 97 dB/mW. The iPhone manages 3 mW for a load like this, so we're looking at maybe 101 dB max. Weak sauce, particularly since that's the loudest possible volume and the average volume for most recordings (that aren't Metallica) will be quite a lot lower. (If you raise the average levels with a maxed-out amp, the peaks won't get any louder, but they will clip and distort.) Compare the PM3: that one does 101 dB/mW with impedance around 30 ohms. With 25 mW from the iPhone, we end up at 115 dB; much more potent. You'd need 60 mW at 300 ohms (about 25 times as much power) to get the same volume out of the HD600.

After power, the next challenge for the amp is to not ruin frequency response. That's hard for one big reason: the impedance of dynamic headphones (all of them unless labeled orthodynamic or electrostatic) changes with frequency. It might be 200 ohms at this frequency and 400 ohms at another. If the amp's output impedance is zero, that doesn't matter. If it's more than zero, the voltage sent to the cans (and by implication how loud they are at that frequency) will change over the frequency range. Whatever response curve Sennheiser had in mind ("Ve shall haf 14% less zeebilance"), high output impedance can result in something very different. This is why it's hard to take subjective opinions seriously if you don't know how the headphones were driven.

There's another benefit to low output impedance: better bass control. Speakers tend to get sloppy and distort with frequencies near their resonance peaks. That manifests as a muddy, definition-smothering bass hump. The best way to prevent this distortion is with electrical damping, the ability of the amp to electrically prevent unwanted movement (in the same way that it's hard to spin a motor if you've shorted the power terminals). To keep the bass tight and changes in frequency response inaudible, the amp impedance needs to be, if not zero, at least 8 times less than the headphone impedance. A few inexpensive devices pull this off with just about every can (e.g., the original Sansa Clip+ that measures 1 ohm), though not many (the various iPhones tend to be 5-10 ohms).

Everything else about amps starts to get subjective. To me, the perfect amp has zero distortion. To the folks buying tube amps, distortion is the whole point. Same thing with deviations to the frequency response curve; best-case, it's flat over the entire range, but if the "house curve" of your headphones is the typical V-shape with an emphasis on bass and treble, an amp that rolls both ends will make the cans an easier listen over the long term. Tube amps usually attenuate the high end; since the classic "audiophile" curve has strong treble to emphasize detail, softening that treble peak quite often sounds better.

Anyway, long story short, if the open design of these HD600s didn't already to consign them to home use, their high impedance almost certainly will unless you want to supplement your traveling kit with something like a Fiio E07K.

HD600 vs. HD650:

The HD600 is one of the most neutral headphones available. Everyone says that about speakers they're used to that don't have glaring response anomalies (and sometimes even if they do), but it's true here: the correction to flatten the HD600's frequency curve is minimal. Music tends to be mastered with a neutral output device in mind; if your hearing isn't unusual, neutral cans are likely to sound good over the broadest cross-section of material.

The HD650 is the same experience less some treble. It's constructed almost identically to the HD600; the $100 price difference is a marketing maneuver that has nothing to do with sound quality. Rolling the treble lends a "warmer" and slightly less detailed sound that'll flatter music mastered "hot" or with excessive treble or bass equalization. ("Warm" in audiophile parlance is akin to warm and fuzzy; "hot" mastering implies that the sound engineer compressed the dynamic range to make everything loud.) The HD650 also won't draw quite as much attention to themselves. Whether that's better is personal preference. The HD700 and HD800 take the opposite approach: you're getting detail whether you want it or not.
 
Incidentally, not all "detail" is the same. Detail comes from boosted treble or better drivers. Lesser cans favor treble. Bumping the high range sounds clear and vivid on first listen, but quickly becomes fatiguing. (Bose speaker demos are notorious for this.) Better cans opt for more powerful, higher-impedance, lower-distortion drivers (or different technologies entirely as with electrostats) so intrinsically revealing that the manufacturer can use a more relaxed tone curve. The most detailed dynamic cans (i.e., the HD800) have only a mild treble bump. Less, even, than the HD700, which makes do with a less sophisticated driver. It's unsurprising, then, that reviewers tend to find the HD700 a little harsh on direct comparison.

You could achieve the HD650's sound by plugging the HD600 into tubes, but if that's really what you want, there's a better way.

SIGNAL PROCESSING:

Here we enter controversy. Audiophile purists believe in maintaining the integrity of the signal from recording to output. 24-bit audio, SAC-D, fancy cables, and giant Class A furnace amps are not out of place in this crowd. I respect the motivations for that view, but I've abandoned it with the HD600 for the better. We've had enormous advances in signal processing over the last twenty years. The HD600 is a mechanical device. It doesn't, and can't, have an perfectly flat frequency response. The cups and driver enclosure impact the sound too much, even if the driver itself could be made perfect, which it can't.

But if we measure the curve, we can recreate any frequency response we want by digitally modifying the input. This is DSP: digital signal processing. The software equalizer in iTunes is a basic DSP, as is Autotune and every "enhance" button you've ever seen in a music player. The processing is almost never "free" (in the sense that it'll only have positive effects), but the benefits can vastly outweigh the downsides.

To jump straight to the point, a company called Sonarworks has measured and corrected the HD600. The plugin is about $70 from them, and in addition to making the HD600 a legitimate tool for mastering, it also improves ordinary listening sessions quite a lot. Bass impact in particular, always a weak point with headphones, sounds speaker-like through it. The Sonarworks VST plugin works through a VST-supporting player like J-River Media Jukebox or any of a dozen VST hosts (e.g, Audio Hijack on Mac). If you don't like the result, you can emulate a variety of other headphones. Grado GS1000? Sure. HD650? Yep. I hate spending money on things that aren't hardware, but in this case, I'm sold.

It gets better. After you've installed that, download Wave Arts Panorama5. It's a very powerful binaural emulator that'll take recordings out of your head and put the singer in front of you. Real binaural recordings use a dummy head with physical ears to create positioning cues that can sound wildly more realistic. Panorama (and free, albeit much inferior alternatives like 4Front and Psypan) use HRTFs (head-related transfer functions) to modify a conventional signal with math to recreate the dummy head effect. Done well and matched to your ears, it can leave you agog. ("Why is my neighbor pounding on the ceiling? Oh. Wait.") Likewise a program called "Out of Your Head," which is expensive because the author measured a bunch of high-dollar audio setups. Want your HD600s to sound (exactly) like a movie theater? That's now a thing.

IN SUM:

To wrap this novel: definitely try the HD600s. They're frequently on sale in the low $200s. There isn't anything as good anywhere near that price. To give perspective, after demoing them against the 400i for a month, an ortho at twice the price that everyone raves about, I returned the 400i. But I'm a home listener. If you're on the go, have small ears, and don't want to annoy everyone, try the Oppo PM3 instead. Truly, you can't go wrong with either.

These are, imo, the best Sennheiser headphones. Among the many headphones I've tried, the only ones that feel really neutral and natural. A perfectly balanced sound, smooth yet very detailed. Bass has very good extension  and awesome overall tone and impact. Mids are magical, dead neutral and flat and you really feel this on voices and strings. Highs are very extended and smooth and there's plenty of detail. An awesome allrounder. Best value headphones out there, with X2 as a close second. Sounstage is very good but not on par in tridimensionality with that of hps such as HD800 and X2.
Build quality is great, very sturdy but light, and they are very nice looking. Cable is good but improvable, HD650's cable is better. Comfort is really great, they disappear after a while and theyb stay perfectly fit even while moving your head. Pads are very comfortable.
I find HD600s better than HD650s, much more natural mids and overall sound , they're more involving with better bass (hd650s' bass has too much mid-bass and less impact). HD650s are still very good though.
X2s have a more tridimensional sound with more bass but lack some naturalness and smoothness in mids/highs, there is a notable peak up there. HD800s have better soundstage but everything else is worse because of another peak in treble and mids are a little too recessed.
Overall HD600s are to me the best hps out there because they are very good at everything and have no big weaknesses, altogh newer hps may be better in specific fields. They are the only ones with a totally neutral, smooth and balanced sound. Very very pleasing, I consider them my reference headphones to compare others to. Definitely a MUST-HAVE.

After over two decades of service, the HD 600 is still going strong. Since the early days of its introduction, the HD 600 has grown to become something of reference point within the audiophile community. Furthermore, its neutral, airy sound has made it a favorite among audio engineers. As such, you will struggle to find better at this price point. Now, please enjoy the video, it offers my full opinion on the HD 600 as well as a touch of comparison between it and its sister, the HD 650. If you have any questions please, feel free to ask. Thanks for watching.

The Sennheiser HD600 is an open dynamic circumaural head-phone which Sennheiser market for audiophiles, and also state as ideal for studio monitoring.
 
 
Pre-amble (about me at time of writing)

I'm a 44 year old music lover.  I don't say audiophile - just love my music.  Over the last couple of years, I have slowly changed from cheaper listening set-ups to my current entry/mid-fi set-up.  I vary my listening from portable (i-devices + amp) to my desk-top's set-up (PC > coax > NFB-12 > HP).  My main headphones at the time of writing are the Sennheiser HD600s, a modded set of Alessandro MS1i, and a set of B2 iems.  I previously owned Beyer DT880, Shure SRH840 and 940 + various other IEMs. I have auditioned quite a few entry and mid-tier cans, but have yet to hear any flagships (at current time of writing this review).  I have very eclectic music tastes listening to a variety from classical and opera to grunge and hard-rock.   I listen to a lot of blues, jazz, folk music, classic rock, and alternative rock.  I am particularly fond of female vocals.  I tend toward cans that are relatively neutral/balanced - with a slight emphasis on the mid-range.  I prefer a little warmth in the overall signature.  I am neither a bass or treble head.  Current amps = NFB12, GoVibe PortaTube, Fiio E11.  Previous desktop set-up was a Fiio E7/E9 combo.
 
Packaging and Accessories
I purchased my HD600s from another Head-fi member.  They come with a very solid and well padded case, and a 3.5-6.3mm adapter.
 
Technical Specifications
From the Sennheiser website :
 
Nominal impedance = 300Ω
Contact pressure = ca. 2,5 N
Weight w/o cable = 260 g
Jack plug = 3,5/6,3 mm stereo
Transducer = principle dynamic, open
Ear coupling = circumaural
Cable length = 3 m
Frequency response (headphones) = 12 - 39000 Hz
Sound pressure level (SPL) =  97 dB at 1 mW
THD, total harmonic distortion = 0,1 %
 
Frequency Response Graph
(From HeadRoom)
 

 
 
Build / Comfort / Isolation
The HD600's build is solid - but not 'bullet proof'.  They are very light-weight (plastic headband - with a carbon fibre inner band) - but they are well put together.  If I had one criticism, it would be that the headband is not as strong as I expected.  When I got mine, I found them a little 'clampy' - so thinking the carbon fibre inner would be strong enough, I tried to stretch them to alleviate the clamp.  Big no-no.  Snap!  One broken headband, and me almost shedding 'manly' tears.  Admittedly, I stretched more than I should have - but it was because I expected the carbon fibre to allow the plastic outer to bend.  Anyway  - you have been warned.  I'll tell you how I fixed them down the page shortly.  The shell is plastic (very light) with some plastic moldings - the outer shell has a marbled look - that I think actually looks quite classy.
 
 
 
 The headband padding is actually very soft and extremely comfortable.  The ear pads are a soft velour which has quite deep cups, and are also very comfortable.  Note - after a while you get used to the tight clamp - and I've found I could wear them for hours.  They would be the second most comfortable headphones I've owned - just behind the DT880s.
 
 
 
These are an open can - so there is no isolation in or out.  They are not as bad as a Grado - but they are open.
 
The huge benefit with these cans is that they are completely modular - you are able to break them down fully, and all parts are replaceable - even the drivers.  So after my "mishap" - I got in touch with Sennheiser, and they had a replacement headband on it's way to me.  It was a very simple operation to dismantle the headphone and swap the parts out.
 

 
The cable is also replaceable, and you can go after market if you wish.  Personally I find the stock cable to be very sturdy (advertised as OFC copper and kevlar reinforced) - and it doesn't seem to be prone to cable noise or tangling.
 
Listening Set-up
My main set-up with the HD600 is PC > Coax > NFB-12 >HD600.  For a transportable rig, I use iPhone4 > PortaTube > HD600. 
 
Sound Quality
These are very simply "keepers".  They are the most natural sounding headphone I have used or auditioned to date.  They are very well balanced across the spectrum - with a slightly elevated mid-bass and lower mids.  Overall I would call the sound slightly warm without being dark.  I used to play guitar, and have spent time in my youth listening to live orchestra and solo violin - and I found the HD600 to be quite realistic.  A quick summary of the main sound quality headings:
 
Detail - While not as detailed as the DT880, I found the detail on these still quit high.  They do tend to be slightly laid back, and can get slightly congested with very fast music.  The clarity is very good.  I find them articulate and refined.
 
Sound-stage - Similar to the DT880 in overall size.  Depth and width ifs quite good, and instrument separation (particularly for classical) is quite good.
 
Highs - These surprised me.  They are nowhere near as etched as the DT880, but I don't find them veiled at all.  For me the highs are quite natural - no trace of sibilance or harshness, with still good detail.  Highs are not the focus, but they are still presented beautifully.
 
Mids - IMO this is where the HD600 really shines.  Acoustic guitar (any stringed instrument really), piano, and female vocals especially are wonderful on the HD600.  I recently bought Alison Krauss and Union Station's album Paper Airplane.  The combination of Alison's vocals and the bluegrass flavour of the music is simply divine.
 
Bass - on the NFB-12, the bass is well defined and punchy - with good impact.  it just doesn't reach low into the sub-bass like the DT880.  But it doesn't need to - because once again the bass is beautifully balanced with the rest of the frequencies.
 
Power Requirements
The HD600 has 300 ohm nominal impedance - but what surprised me is how easy these are to actually drive.  They do sound wonderful out of the NFB-12 and also my PortaTube - which both have plenty left on the pot.  But I can also play these easily on the little Fiio E11, and even out of the headphone out of my iPhone4 (admittedly on about 80% volume).  On the iPhone4 unamped, the bass becomes quite boomy and muddled - so it's obviously not being driven properly - but these don't require huge power.  They do seem to scale well - the difference between E11, my E7/E9 (when I owned it) and now the NFB-12 is noticeable - with extra body and definition from the NFB-12.  I'm looking forward to trying these with a Schitt Valhalla sometime next year.
 
Summary / Conclusion
The HD600 has become my favourite headphone for simply listening to music.  They are well built, comfortable, and sound simply phenomenal.  Their tonal balance and the naturalness of their sound is the best I've personally heard so far.  While I wouldn't recommend them for critical listening (the DT880 is better for the extra detail and extension it brings), for non-critical listening enjoyment - there are few better IMO.

There's not much for me to say about these as they are perfect headphones that deserve to be in everyone's collection.

The HD600 is a legendary headphone and rightfully so.

When listening, you will hear a full track portrayed with excellent detail, with great resolution.

They sound they produce is out of their price level, sounding multiple times their price and the midrange is simply benchmark.

The timbre is fantastic, vocals sound totally natural without any weird colorations.

They are clean and clear. Bass is punchy, midrange is just right, treble is detailed and fast.

I'll let the more experienced reviewers give you dirty details, but let me just state that these are a masterpiece headphone which deserve all of the praise they get and will continue to get.

They just sound right. Masterful headphones.

If you are the type of person that just wants one do-it-all headphone around $250, grab these and enjoy most of what this hobby has to offer.

Plus, how could you not dig this kitchen counter appeal?

They are AMAZING headphones, if you like neutrality and clear audio, there is really no competitor, Grados 325e? Not even close, Audio technica r70x? You're kidding me.
I can't emphasize enough, YOU NEED THESE HEADPHONES, they make sub-par songs sound great, you will love them, no matter how expensive your current headphones are. No more needs to be said....
 
 
 
 
 
 
 
 
 
 
 
HURRY UP AND GET THEM!

Here's a quick summary on the HD600. I am going to leave out headphone specifications because you can find them on Sennheiser's website. These are open cans ,not suited for portability, and they do require amping (300 Ohms).

Comfort
They are very comfortable and my ears don't get too hot after listening for quite some time. The cups are quite deep and I like it that way. I had hours of listening enjoyment with it and so far had no problems with comfort.
 
Sound Quality
Wow, these cans sound completely natural! I know the differences between natural and neutral but the HD600 has both elements. Although Sennheiser has been long associated with a veil, the HD600 does not seem to have any. SQ is completely transparent and I can assure you that the HD600 has no veil at all.
 
The HD600 is very detailed although not up to DT880's level of detail. For classical music, hands down the HD600 is the king. Violins are wonderfully textured and have a fantastic weight on them. Highs and mids were fantastic and the bass has great impact and that nice punch in them. The HD600 is no slouch, it is aggressive and sound very neutral and balanced across the frequency range. 
 
It did a great job in instrument separation although the size of soundstage could be bigger. Don't get me wrong. Its soundstage is fantastic and has the characteristics of an open can but vocals are more upfront and intimate. 
 
Quick Comparison to the HD650 and HD800
 
Neutrality: HD600 > HD800 >>>> HD650
The HD600 is the most neutral among the three cans although as mentioned the soundstage should be a tad bigger. HD650 to my surprise is dark sounding, veiled and coloured (in a good way). It has more bass than the other two headphones. The HD800 has slightly too much treble in my opinion.
 
Soundstage: HD800 >> HD650 > HD600
No challenge here. The HD800 is the clear winner.
 
SQ: HD800 > HD600 = HD650
The HD800 has a much better presentation and detail retrieval than its younger siblings. On the HD650 & HD600, it's a matter of preference really. If you like listening to pop/rock, it's best to stick with the HD650. And if you like uncoloured headphones or listen to the music audio engineers intend them to be, go for the HD600 and ultimately the HD800.
 
 
Conclusion
Amazing cans and they deserve the title of a legend. They are worth every penny and imho is a top tier can. Comparing them to the Beyerdynamic DT880, I cannot say that they're better/worse than them but all I can say is that both cans are one of the best headphones out there and they compliment each other. When listening to classical music I always reach for my HD600. They are simply astounding and sound heavenly in your ears. 

Introduction
 
This is a review of the Sennheiser HD600 headphone. The HD600 has been one of the most respected headphones on the market for nearly twenty years. This review will cover construction, comfort, power requirements, sonic performance, comparisons with other headphones, and a conclusion about this world-renowned headphone. With that, let;'s begin.
 
Technical Specifications
 
Nominal Impedance 300 ohms
Weight w/o cable  260 gm
Jack plug  3.5/6.3 mm stereo
Transducer type  open, dynamic
Coupling  circumaural
Cable length  3m
Frequency rewponse  12-39000 hz
Sound Pressure Leveel (SPL)  97 dB @ 1mw
Total Harmonic Distortion (THD)  0.1%
 
 
 
Accompanying gear for the review
 
naim cd555, iphone 6S, MacBook Pro, ipod shuffle 2G, DK Designs VS1 Mk III, magni2/modi2, Bravo Ocean, Audio Note Custom 300B, HD598, HE400S, HD600, 
 
Comfort and Construction.
 
The HD600 is constructed primarily of plastic with a small area of carbon fiber on the band. The pads are velour as is the headband, which makes for substantial comfort. Clamp force is fairly snug, but I can wear this headphone for hours with little discomfort. I have an average sized head. There is plenty of room in the band for those with larger heads. Overall, I would say this is a well-constructed headphone--and it must be because there are people out there who have had theirs for a decade or more.
One final note. My HD600 is brand new and it is not of the blueish hues that 600s of days past have been finished. Mine is black and the top of the band has a black and grayish paisley-like pattern where the word 'Sennheiser' appears. It is quite a beautiful headphone and is much better built than my HE400S is.
 
Power Requirements
 
I used a wide variety of power sources for this review. What I can tell you is that the HD600 requires a decent amp in order to shine. My ipod shuffle will drive them to loud levels, but it will not provide adequate power to support solid bass and optimal midrange. So, if you are looking at an HD600, be sure to budget for a good amp. You see the ones I use and they all drive the 600 to lovely heights--even the Ocean.
 
Preliminary Impressions
 
My first impression of the HD600 was of its detail On Pat Metheny's As it Is, the vocals were lush and rich, with individual vocal lines etched out from one another. The air around the voices was clearly audible.I smiled. I knew I was on to something. On Stravinsky's Rite of Spring, the woodwinds blaze a blistering path through the piece. I am in the room with them. They are real. The timpani are blasting acoustic energy at me, their echo clearly audible. On Larry Carlton's Last Nite, Carlton's guitar is harmonically layered like the steps of a stairwell. On Metheny's Minuano, something important emerges. It has to do with the treble. More on that in a bit. On Captain Fantastic and the Brown Dirt Cowboy, Davey Johnstone's guitar is lush and rich. I have never heard it sound so good. Wow!
I keep spinning the music. And I sit back and listen. And settle in. It's going to be a long session.
 
HD598 vs HD600
 
The most profound difference between the 598 and the 600 is that the 598, which I like very much, has sluggish and muddy bass by comparison. It is very sluggish and cannot keep up with the music. This is true on the Pat Travers' Band's Heat in the Street, where the 600 is like a fine German car. The 598, tries its best, but it's an old out-of-repair Nova and it just can't keep up.. That said, the 598 soundstage is clearly better and wider than the 600's is. There is no doubt about it. Instruments occupy a much vaster space with the 598 than they do with the 600. Treble isn't as good with the 598. More on that later.The midrange on the 598 is very nice. But it can't compete with the 600. Vocals in particular are widely different on the two. The 598 is good. The 600 is superb.
 
HE400S vs HD600
 
The HE400S is a very good headphone. It has a gorgeous midrange and very nice treble. However, its bass is fairly rolled off starting at around 70-80 hz or so. Sub bass is kind of weak. This is especially notable on song's like Fourplay's Elixir, which has deep bass. The power of this line is lost with the HE400S. The HD600, on the other hand, plays that line with impact. It is not as powerful as my HD681 Evo, but it is still felt and heard. The treble is very interesting. On the aforementioned Elton John and Pat Metheny songs, the drummers use multiple different crash cymbals. On the HE400S, those cymbals all sound fairly similar. On the 600, on the other hand, those cymbals are all each totally unique and distinct sounding. It is remarkable the resolving power of the 600 compared even to the very good HE400S. With midrange, the 400S is thin sounding by comparison to the lush and rich 600. everything is just thinner. It still sounds good, but it is rendered less resolving and full by the HD600, which is just stunningly neutral.
 
On Neutrality
 
My definition of neutrality is a headphone that sounds good on  good recordings and like crap on crappy recordings. In short, it spits out what it is given without adding or subtracting anything appreciable This is what the HD600 does. It adds little and subtracts less from the music. In short, it is a remarkably neutral headphone that is a joy to listen to. Run out and buy two--you'll be glad you did.
 
Conclusion
 
The Sennheiser HD600 is a tour de force, lo these many years later. It has an absolutely spectacular midrange, exquisitely detailed treble, and a bass and sub bass that is more than adequate for me. They are musical. They sound like music. Not many headphones can say that. Though its soundstage is smaller than the 598 and HE400S, the 600 images quite well. Instrument separation is superb. It conveys the emotion of the music beautifully. As I alluded to above, run, don't walk, and pick one of these up. You'll find yourself listening for a long, long time.

Intro

Im a relatively new "audiophile" although I, like many others, have been a long time music listener. Like the teenage stereotype, details weren't important to me, but as I started to listen to music from the likes of Kenny G, I felt the thirst for detail as the earphones I owned (UE400s) just didn't deliver the sound I was after. Bass and treble were the focus, as it is with many of the current head/earphones today.
A while later, I received a pair of UE Super Fi 5's which were great but I felt myself struggling to enjoy the sound right out of the box. It wasn't long until I discovered my drive for high fidelity audio. The bass was punchy, the highs were very detailed and the mids were the focus, making them an intimate IEM which I enjoyed for 2 years. One day, I found myself with a wad of cash which I initially intended to spend on an Amp and DAC.. until I stumbled upon a pair of HD 600s for sale... which funnily enough, belonged to Brooko!

Impressions

These to me, have been the headphones ive been yearning for! They're perfect. My ears are sensitive to high frequencies and get fatigued very easily, but due to the highs being slightly laid back, I find myself listening for hours and hours a day without hearing a hint of sibilance!
The Bass is punchy and detailed without being boomy. The mids.. are absolutely stunning. The realism and intimacy is nothing short of overwhelming. Vocals and many instruments, sounded incredibly natural with timbre. The soundstage could be better at times, although I really do enjoy the intimacy it offers with most of the songs I listen to.
 
*My apologies for the link! Its a link to the image I wanted to upload here, but hosted on facebook. Its no virus afaik. The last thing I want to do is get banned after my first post! Ive tried countless times to upload a pic but when i click on the "insert image" button, it says "please wait" and nothing happens. Id be grateful of any help as I am a newbie to Head-fi, although ive read a lot over the past few years. I also dont know how to respond to the comments below, but I do appreciate the feedback! Thank you!*

Dear Head-Fi community,
 
By the time you get to my short review I am sure you have read many other reviews for this popular set of cans. So without elaborating on the wonderful mids, the neutral sound, or great soundstage I would like to share my favorite attribute of these wonderful cans. These of all my cans I keep coming back to even though I have superior headphones. I find they are the most sonically comfortable for extended listening of any of my headphones and I find myself shelving my Beyerdynamic t1s and Audeze in favor of my HD 600s during a long project for quiet background noise. I recognize that in nearly every aspect the other cans sound better and I do prefer them for serious listening and movies. But something about my HD 600s makes the very comfortable to listen softly for hours at a time. In order to try and quantify this preference I have tried several different cables and light modding. Following this I discovered that the only thing that seemed to affect this attribute was the simple foam mod (removing 4 pieces of foam around the driver. At first I noticed that the Sennheiser veil that many people complain about was lifted and I seemed to get a better bass and treble response, however after a long session I discovered that I could no longer wear them for extended periods like I could before. With most things headphones things become very subjective, however if you are considering these awesome headphones don't be afraid to give these a shot because they will never leave you tired or strained.

Let me just say one thing up front: if you have any complaints about the speed or the bass extension of these headphones, you need a better headphone amp. /endofdiscussion The HD600s will take the best in source material and amplification, and give you the best sound in return. It's not coincidental that these cans are held up as the reference's reference: more than any other headphone I can think of they sound like whatever it is you are listening to. Their most notable audio characteristic is this ... amiable compatibility. That and the ability to play cleanly at very loud peak levels. Combined, the HD600s are ready for whatever you care to throw at them, never drawing unwanted attention to themselves, always sounding great.
 
Perhaps part of the secret to this neutrality and high enjoyment factor is the way they dial down the resolution just a tad. A fraction de-focused, one notch less treble intensity - blending the music into a coherent experience rather than individual strands of detail. Some people might disapprove, I call it genius.
 
These are comfortable, durable headphones built to a high standard. The foam pads on the earcups and headband died after a decade or so, but I easily replaced them with the new parts from Sennheiser.

Simply amazing!

You know them, he knows them, they too, everybody does. So what are these?

From their first debut in 1997 to today, the HD600 and HD650 have been one of the most loved and used headphones in the audiophile community.

What made them so special? What was the key that Sennheiser managed to develop to let them stand to the testament of time?

Let's find out.

Packaging and accessories:



Pretty basic I would say, with a nice presentation.



That's the big chungus of the boxes.



Black cardboard on the outside, gray foam on the inside. As you open the package you'll find the warranty and the instructions, under it lies the headphones themselves with the cable and a 6.3mm adapter.



Sennheiser proprietary connector ... Atleast left and right are weel identified.
As you can see the left one is a bit bigger and you can insert them only in one direction, with the letter pointing on the outside of the cup.

Build quality and comfort:



The HD600s are built really nicely, even tough they are almost entirely made of plastic, they feel sturdy and light at the same time, not quite flexible, but enough to make you think these can last years to come.

The cups are of an oval shape and they are tilted a bit, they can pivot and swipe up and down. They are covered by a metal grille to protect the driver from dust and objects. The velour pads are really nice but pheraps a bit stiff, I wish they could be a bit wider.

The pieces that connects the cups to the headband are made of steel, you adjust these depending on your head size.

The plastic headband is heavily padded with 4 nuggets of what seems foam, but I can't really tell.

You might ask what's the strongest point of this old yet extremely practical design... And it's the capability to take it apart by hand and reassemble it like you drink water.

Now, that cable... It's too damn long and it's thick as spaghetti, 3 meters of spaghetti, I'm constricted to wrap it with a cord.
However it doesn't hold it's shape and it's really light, the 6.3mm adapter is indeed proprietary , but it's pretty nice.



Comfortwise, I can keep them for hours and hours on my head and I don't need to adjust them every second.

Yeah, the clamping force is pretty damn tight at first, and even if it goes down after some weeks, it could still cause some issues.
For example, me, who wears some thick glasses, can't stand to put them on more than 1 minute while wearing the HD600s... They pads presses the ears on them and it literally hurts.
However the clamps manages to make them one of the most secure headphones out there, like, I could run with these, never questioning if they would fall off my head anytime soon.

Power requirements:

I was a bit skeptical about this factor, reading forums, watching videos and learning that they needed an Emotiva A100 (it's a speaker amp and it has an headphone out that is obviously limited for preventing the drivers to explode/going on fire, however you can install some jumpers on the circuitry, bypassing the resistance and giving some FULL FLEDGE 8WPC to 50ohms... To your headphones...) to unleash their full potential.

Now, you can get these at listenable levels through your phone (better would be a DAP), however I can attest that they like a lot of current, as much you can feed them to sound like they would like to.



Obviously you don't have the extreme need of that much current, in fact one of those sub 100 dollars amps can get the job almost completely done (JDS Atom, Shiit Magni, Monoprice Liquid Spark, Geshelli Labs Archel Pro... Etc.), but be sure to pick one up while you're at it.
They have an extremely good sinergy with tubes and if you can make them balanced too, that would be amazing.


Sound:

Here's the answer to the questions at the start of this review... It's really simple.

There's nothing special about the driver, it's just a thin plastic diaphragm with a coil and magnets behind it.
And it's even littler than the average, having 38mm of diameter.



However... the amount of effort that Sennheiser put into it and it's tuning must have been ridiculously great, this shows you how simple things can get so much up there with work and development behind them.

Sound signature:
Neutral, midrange forward, with a hint of warmth overall.

Bass:
The bass isn't so bad, considering that it's definetely not the highlight of this headphone.
It slaps rather than punchs, it's really quick and works nicely even with EDM or dubstep, even tough there isn't a lot of it, it's enough to hit you when needed and it retains a lot of tightness.

However when you switch to something like the Neon Demon soundtrack or that from Ex Machina I noticed that subbass is a bit subdued and it rolls off pretty fast.
There isn't even a big quantity of it, it's still there, you can ear it, but not that much.
But again, this is not the main focus of the HD600.

Midrange:
In one world, beautiful.
It's buttery smooth but resolving and detailed at the same time, the instruments tend to give the illusion of being played in real life (at the right volume).
And now, the vocals.

They are BIG and extremely well separated from the mix, with incredible amounts of energy, body and intimacy, I can't prise them enough, definetely the best performer under 500 in this department.

Everybody knows of the HD600 and HD650 midrange, and I think nobody would be disappointed with their performance in this category.

Treble:
I love the treble on these
While not being super resolving, it gives the music a good amount of air and sparkle but maintaining a sense of fullness to them that I personally enjoy.
There are too many people hyping the "veil", I don't think that this is a veiled headphone at all but I can get why they say that:

The highs get better at higher volumes, and I know it sounds weird, but they really open up and breathe when you turn up the dial.

They don't ever offend until you blast them to ear-damaging levels, and since I'm a bit sensitive to treble, I absolutely like this capability.



Imaging and soundstage:
The imaging is good and pretty accurate but it can get a bit lost between the center-side space, nothing mind blowing.

Same goes to the sounstage, it's an intimate headphone, the sound stays between the two drivers, however when you catch that crazy wide song these manage to display that.
The sound is presented more in front of you rather than inside your head, and it's not very deep.

Resolution/naturalness/tonality:
The HD600s doesn't have the most amazing detail retrieval out there, but it's great and will surely not left you wanting for more.
Naturalness and tonality are another story, these are the strongest points of this headphone, going toe to toe with the 1000$ offerings out there... They sound just "right", nothing feels out of place and the music just flows, it grabs you and you're there. Certainly the smoothness contributes to that.

Conclusions:

The HD600s get my full recommendation, for everybody.
These don't soud almost like anything and they show you what a simple, well tuned driver can deliver.
I can't get enough of their smoothness and naturalness, they even have the potential to be an endgame for somebody.
However if you want something more fun, I'll rather look at something else, I don't consider these boring, but ymmv.

So, ladies and gentlemen, thanks for reading, catch you next time, ciao!

Most Musical and enjoyable, Sennheisers most comfortable, Does not need amp, great treble extension paired with correct source, very nice bass.
 
Out of all my cans this is best overall and most enjoyable sound. The HD650 right there but it does have a diffrent sound. I would say Q701 are a great headphone but missing bass.
 
Have: Grado Sr-60, HD555, HD595, HD600, HD650, ATM-50S, Ultrasone HFI 780, AKG Q701, Bose QC15
Had: Grado Sr-80
 
 
Worst headphones: Grado SR-80 and HD555(tried twice)
 
I am sure the $1000+ headphones are better paired with a great amp but this is what I have.
 
The Sennheiser are by far the best brand with combo of great fit, great finish, great comfort, great style, and great sound.
I started with Sr-60 and  wanted to go up with higher models with the Grado but the comfort is terrible. Bowls or Pads. Grado has great sound but after years of wearing them and then trying other headphones. I could never wear grado's again for more than 2 hrs at most every couple of months.
 
I use an STX and Audigy 2 sound card.