KRK KNS8400 Studio Headphones

General Information

Looking for a pair of headphones that are specifically designed to replicate music as it should be heard with the ability to satisfy experienced ears? Get your head around this: KRK has always been focused solely on accurate monitoring. The KNS8400 headphones have the ability to reveal exactly what you have on the tracks and are becoming the headphone of choice for critical mix analysis be it good, bad or ugly. After all, hearing what is wrong with your mix is just as important as hearing what is right! Temperature sensitive isolating memory foam in the ear pads help isolate your mix from open microphones, minimize live instruments from competing with what you are monitoring and because they gently conform to your unique head shape you’ll be comfortable wearing them all day.

Latest reviews

Pros: Clear low, mids, highs; VERY detailed for the price and has a nice extended range
Cons: A little low on bass, very nuetral and has a flat sound, Small soundstage
First off, let me say that if you value clarity and like the details in your music, this is for you. I can't stand skullcandy headphones with its booming bass and muddy mids and highs. This is really one of most detailed headphones for the price, and there is a truly nice extension on really part of the music that is playing; whether it be a cello, guitar, piano, edm, or something in between. This headphone reveals details I never knew existed in the music. As I said, if you like details, and lots of them, the KRK KNS 8400 is the best match for you. Not to mention this is THE clearest headphone I got for the price (at $85) and even going up to... really anything besides for the ath-m50's, which for sure don't have the level of detail this does. 
Remember that the 8400's are monitoring headphones - they are neutral and flat sounding. Keep in mind that nothing will jump out at you with a level of lively attack, for lack of better words. That being said, SINCE there are no sharp peaks anywhere in the sound chart, you could listen to these for hours on end without feeling fatigued. From previous headphones where I couldn't listen for more than 45 min. at a time, my first time with these I listened for 8 hours straight on a plane without ear fatigue. And it only got better from there. Definitely a huge plus if your an avid listener.
Don't think though that these will suck the musical part outta the music and make it boring. On the contrary, I like "feeling" the music and getting into it - these definitely are good for casual listening too.
Isolation is quite amazing from what I'm experiencing - I can't hear people when I have them on. And these don't even have active noise canceling.
Comfort is great - besides for being able to listen to these for 8 hours straight, the earpad comfort has been great from the start and just got better over time. Keep in mind the top of the headband can get a bit stiff - maybe you might want to replace that with something a bit more comfortable. Earpads are memory foam and a barely feel it when it's on my head.
These are amazing; definitely an audiophiliac sound on a low budget. Keep in mind though the flat-ish sound, the soundstage being a bit small, and the 8-foot cable. 

If you enjoy and appreciate your music, ignore what everybody else says and get these. I've listened to a lot of headphones and this one takes the cake.
Oh, and make sure give it some burn-in. LOTS of burn-in.
You cannot fool these headphones. If it's a lousy recording, you will hear it. A lot. If it's a great performance though, well, you'll hear that too.
Enjoy the KRK!
The 8400s are definitely good at details for the $$. That said, I find them more fatiguing than my HD280s or my Aviators.

BTW, while they're all south of $100, my Aviators were the least expensive, the most comfortable, and the best sounding in my opinion. To be honest, if I'm listening to music for the pure joy of it, I'd go with my Skullcandy Aviators over either of these. But don't take my word for it --- listen to Tyll & Jude...or better yet, listen to some Aviators! :wink:

Tyll (if anything he thinks the Skullcandys have a little bass rolloff)
"I spent a while comparing the Aviators with other strong competitors in it's category at large, including: the Audio-Technica ATH-M50; Sennheiser HD 280 Pro; Shure SRH840; Sony MDR-V6; Sennheiser HD 448; Shure SRH750DJ; and, Phiaton PS 500. Apart from the bass issues, the Aviator bested all but the SRH840 to my ears in terms of a balanced sound. The Aviators are solid performers in this category. "Wait ... wut? ... Skullcandy competitive in sound quality?"

Bring your high-bitrate or lossless music to bear on the Aviator (through your own rig), and I think you'll be very impressed. I certainly was...Again, the Aviator is extremely comfortable--I've since worn it for hours at a time, several times. And, most importantly, the Aviator sounds good. Excellent, in fact, for a $150.00 closed headphone...the Aviator excels at all musical genres I listen to (and that encompasses just about everything), which for me is one of the hallmarks of a headphone I can easily recommend, and so I will. When asked for an audiophile-quality full-size closed headphone in the sub-$200.00 price range, I've been first recommending SHURE's SRH-840. When asked that same question now, the Skullcandy Roc Nation Aviator will certainly be added to the list.
The Skullcandy Aviators are known to have a clearer and more balanced sound than any of the other skullcandy headphones. Skullcandy's signature booming bass does not apply there. When I mentioned skullcandy, I meant the run-of-the-mill kind. Forgive me if I didn't elaborate.
Anyway I think the Aviator's don't have anywhere near the amount of detail that the KRK's have... but what do I know? I'd have to have another listening round with them to tell for sure. Also, I've heard complaints about durability and comfort.
The KRK's are fatiguing? Did you burn them in enough? 
The HD280s actually seem dead neutral to me but I could be biased. Definitely the least bassy headphone I've used. Aviators I found lower resolution, bassier, muddy, overall less accurate. I think anyone attracted by what you've said about the 8400 here should also consider the 280 Pro, what you've described sounds very similar.
Pros: Detailed, Accurate and a Fantastic Bass Response
Cons: Could be more isolating
Just a quick review of the KRK KNS 8400 headphones.
For listening and mixing i use a combination of the KRK KNS 8400's, AKG K702's and the Sennheiser HD 650's and these headphones really do hold their own.
To my ears these headphones are brilliant for listening to punk / rock / metal etc and i don't believe them to be as cold and analytical as some may say and really bring tracks to life such as Bring Me The Horizons latest album 'Sempiternal' producing a very well balanced sound with just the right amount of bass.
For my preference i don't like their to be a boost in the bass frequencies so their sound is exactly what i'm looking for and i even use them for music listening out and about. The only thing i will note is that sat on a Bus they don't isolate as well as i would like, letting a little too much rumble in. Other than that i can't complain.
When mixing late at night (when speakers aren't really an option) they really can show me the flaws of a song and later the headphone will translate well to speakers.
These headphones are primarily designed for studio use and for that they work excellently and i have used them for tracking vocals for the artist, tracking drums when on location for myself and as previously mentioned late night mixing and they have never let me down.
Obviously not as great as my beloved HD 650's but they aren't too far off the mark in comparison.
I run them from an Apogee one which powers them just fine and they work almost as well directly out of an iPhone 4.
I use these headphones with the shorter cable which are hard to find in the UK but their is one company that imports them in for under £30 which makes cable complications non existent.
For the price they are a brilliant set of over ear headphones.
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Great review. I would also suggest GMP 8.35D Monitors, it might fit your taste too. More durable and isolating also.
Thanks for the suggestion.
I've been reading more around head-fi and i'm not really hearing the soundstage problems people are talking about.
Perhaps their is a difference between the models that came in the box with the white plastic in comparison to the ones that come in the box with the clear plastic.
I'm going to A/B them further with the HD 650's to compare but i haven't been notably disappointed by the 8400's soundstage.
Toms rolls are quite wide when listening to metal, coming in from the side then rolling in front of you and off to the other side like you were in front of the drum kit.
I'll admit the soundstage isn't as good as the HD 650's soundstage but their closed back. I haven't heard the ATH-M50s or the Shure SRH840/940 yet, so maybe their soundstage's are more impressive.
Pros: Replaceable cord, very detailed, lightweight, many wearable positions
Cons: Incompatible with glasses, small soundstage, bass light
[size=medium][size=10pt]These are my first pair of headphones (ever), so take this review with a grain of salt. I never used headphones before because I didn't see why I ever need a pair. My speakers were fine and I don't listen to music seriously when I'm outside of my house, so it would have been a waste of money to me. I did however use a cheap, poor quality pair only for some brainwave entrainment experiements. I never used those for anything else in fear of becoming accustomed to bad frequency response. The reason why I'm trying headphones again now is because my speakers lack in subbass, they disturb others if turned up too loud, and I wanted to a more detailed way to view music. My review probably won't be relevant for most of this site, BUT it may help other first time headphone buyers if they are interested in the 8400 being their first higher end headphones as well. I only have the Creative X-FI Go Pro so that's the only amp I can do this review with (yeah, I know it's not high end at all - limited funds means I need a bare bones solution). My ears prefer colored, fun sounds, but my brain prefers accuracy and would rather bite the bullet until it sounds pleasing. These KRKs were cheap (in terms of headphones), somewhat newly introduced, aiming for neutrality and maximum details, have a minimalist design, and feature a replaceable cable and memory foam so they looked like the perfect no frills all-in-one solution.[/size][/size]
[size=medium][size=10pt]Personally, I don't care about packing. It could be sold in a plain white box with a simple text label on it. However, mine had the clear plastic shell it came in (there may be variations based on the holding piece inside).[/size][/size]
[size=medium][size=10pt]I must be in a minority on head-fi or such, since plastic, "gaudy", or "less sophisticated" headphones appeal to me. Anything with wood or an older design turns me off. Anyways, to me, these headphones look like inexpensive matte plastic, and I like that. I like their minimalist, just the basics, look too. They don't look cheap, but they don't look expensive.[/size][/size]
[size=medium][size=10pt]Build Quality[/size][/size]
[size=medium][size=10pt]They are surprisingly lightweight. They are made from impact resistant materials throughout and thank god too. Before I had a chance to tie the headphone's cord up, they fell to the floor over a dozen times from a little over 2 feet. However, they are fine and sound the same. Another big reason I chose then is due to the replaceable cord. It is only a matter of time until I step on it and that's that. At least then I will be able to replace just the cord. It's really easy to snap in and out of the socket too.[/size][/size]
[size=medium][size=10pt]Depending on the position, they have a bit of a clamp to a little less. They aren't going to fall of my head but it I can tell they are there. The memory foam on the ear pieces feel pretty invisible to me (I don't really notice them), but the headband material is a little firmer and has sometimes become slightly painful/uncomfortable after long sessions. Overall, they fit ok. The reason why I'm only saying ok vs great/good/etc, is because they fit in A LOT of positions. Exactly where/how I should be wearing them? I'm serious. I read on the forums that other headphone manufacturers try to dictate where they sit, but the 8400s are completely the opposite. I can wear them from 0-4 notches down, in a middle, forward, or back positions as well. It isn't a perfect 12 positions, but it's quite a bit.[/size][/size]
[size=medium][size=10pt]Sound Isolation[/size][/size]
[size=medium][size=10pt]These block a surprisingly amount of sound both in and out. I don't have any really formal ways to test it, but if I play at a comfortable volume and stick them on a wig head, I have to concentrate to make out leakage.[/size][/size]
[size=medium][size=10pt]Lean, controlled, and bit shy. It's enough to be there, but it doesn't have any real presence. Midbass is ok and present, but the subbass is buried. You can tell if you take it away, and in test tones it shows up, but in general use it's a bit hidden. I would prefer more, but depending on the mix, it's ok. Some say they have a bit of midbass bump and I can't tell if I hear it or not (am I hearing a midbass distortion that's contained in the song or actual frequency difference?)[/size][/size]
[size=medium][size=10pt]There's nothing that stands out about the mids to me, maybe they lean a tiny bit bright. I read there was a bit of 2.5k bump. For the most part, this is not noticeable. But on songs like Marina and the Diamonds – “Primadonna”, the vocal enters piercing territory.[/size][/size]
[size=medium][size=10pt]I don't think its fatiguing, or that there is an emphasis on it, but the fact that the bass is not as impactful and the mids don't have anything to draw my attention (like a huge flaw), I feel it kinda highlights the treble spectrum at times. Some songs I've heard before, I don't remember their snares having being that sharp and having so much punch. The treble can go into the "too much" category if I wear them forward too, almost like that "false detail" sound that sounds ok at first but can't be sustained for long periods of time.[/size][/size]
[size=medium][size=10pt]Speaking of detail, since it's my first pair of headphones, I can't really judge what is too much/too little, detail, but I can say I am definitely hearing new things so these things seem really detailed. Off the bat, I can hear echo decays easier and longer. From there it goes from simply hearing vocals and vocal treatments deeper (like backing vocals or overdubs), to extremely minute details (a very faint midtone buzz from the right channel in the the beginning of Rihanna - "Love Without Tragedy"), to stuff I just don't want to hear (television). The first non-music thing I used these on was the TV show Castle on my computer and it shocked me. The characters were where they usually were (their police precinct), but it's like I could more easily hear room they were in, like the ambiance/echo/shape of the room. It's not something I wanted to hear and was quite ugly.[/size][/size]
[size=medium][size=10pt]I knew coming into headphones, especially closed headphones, that soundstage would shrink, but THIS MUCH? Really? It sounds like when you turn the volume too high and it becomes hard to discern individual tracks and parts. For a couple months, my KRKs were quite "unfocused" sounding, like I could hear what was going on, but there was a "grasp" on what I was hearing that was missing. It's like I would need to strain or try harder to hear everything as effortlessly as speakers. It is still somewhat present but not as much. I went to the glossary looking for adjectives: Here's what I came up with: not airy, no ambiance... closed is a really good description ("Closed-in sound lacking in openness, delicacy, air"), as well as forward ("forced upon the listener"). If the music is narrow to begin in (aka most mainstream music that's poorly mastered), the KRKs can push it over the edge. Having the detail I described before this is almost a punishment then, because it ends up a small space and is a bit overwhelming. It's like 2D vs 3D. All of these details are shoved together between two panes of of glass (2D), instead of having room to exist (3D). Maybe I'm just not used to the lack of air or closed-ness, but I feel really sensitive to air and openness. I can just hear the lack of air and space missing. It almost sounds "sucked out". On horribly mastered loud music, it's amplified even more. One Direction's "Live While We're Young”s is a good example. It's already quite loud and compact in the chorus, but the KRKs make it sound extra compact.[/size][/size]
[size=medium][size=10pt]The tiniest difference in either horizontal or vertical direction changes the sound noticeably. For me, I really hate this aspect because I can put the headphones on all those different ways (that I described above) and end up with a slightly different sound each time. If I have them centered and at neutral level (0-1, sometimes 2 notches), they sound a bit forced upon me and with that "unfocused" quality I described. Move them back a little and they come into focus while sounding denser yet narrower (don't ask me how), more bass impact. Move them forward and they sound less forced, but also sound more detailed, but it can be too much too handle or even more unfocused sounding. Treble emphasis. Simply drop them down to 3, and they open up, sounding less "forceful", and if dropped to 4, they even more so, but then they sound like they are coming from too distant and they feel like they are sitting too low on my head without more dramatic adjusting. I noticed the positional stuff in the beginning of Man Without Country - "Puppets", about the first 30 seconds. It has gone down over time (not sure if it's me or the headphones), but at one point it was simply ridiculous. I could not believe how much the tiniest change made.[/size][/size]
[size=medium][size=10pt]Fatal Flaw[/size][/size]
[size=medium][size=10pt]Not glasses compatible. They feel fine, but sound wise, there is a huge difference! This was brought up by somebody else on head fi so I decided to investigate it myself. My original conclusion was that there was a minor, yet noticeable difference. I removed the plastic tips on my glasses (they still fit fine) and then it was almost undetectable. Recently I got a new pair of glasses though, ones that had a plastic temple at the end again. Tried the headphones with these again and now I can confirm that they just don't work. The temple ends are not big at all and there is nothing about them that stands out as unusual, so I'm ruling them out. Two examples are Sky Ferreira - "One (Bar9 Remix)" at 3:52-4:04, Gorrilaz - "Feel Good Inc." The former doesn't have a huge bass beat or anything, but just enough bass to be present. With glasses on, it disappears entirely. The latter has a heavier bass beat, but when wearing glasses, it lacks impact and substance. Part of it just disappears. The entire sound in general while wearing glasses is extra bass light, emphases on the high end, and more open. It sounds exactly like if you put headphones on (with no glasses) and then slightly open the front of the, so there isn’t a full seal. And It is extremely noticeable. For me, I can kiss all the subbass goodbye with glasses on.[/size][/size]
[size=medium][size=10pt]They cannot be driven with cannot be driven by Realtek Integrated Audio (if you really want specs, it's some 5.1 model from 2009 that I don't think I need to be digging up). Max volume was nowhere near loud or max sounding. I tried the line out, which sounded cleaner, yet lacking in bass, and the headphone jack in the front [/size][/size][size=medium][size=10pt](which are usually of lower quality, hence why I didn't want to use them). I don't use the inline volume cable provided either. It just adds extra length and is another volume control to mess with (I have Windows for that).[/size][/size]
[size=medium][size=10pt]I wanted to love these headphones but I was pretty disappointed for a while. They feel pretty sensitive to start. I would like my headphones to just snap into one spot, like "This is it! The perfect position that feels the most natural and sounds the best." vs having a ton of a positions that feel good but all come with a slightly different sound. And I don't know if it's because I'm extra sensitive to a closed sound or not, but it doesn’t come easily to my ears/brain. By now, I am more used to it and it's not a huge problem, but the soundstage combined with the details and "forcedness" still kinda kills me. I know these headphones aren't supposed to make music sound better than it is, but I didn't expect things to sound this bad. Sometimes they are very easy to enjoy and at other times sound like their only purpose is to induce fatigue as fast as possible. It's not as easy to listen to music for extended periods of time because everything feels very squashed then. It amplifies the 'everything sounds like it's at the same volume' effect of the loudness war. The way I listen to music also involves a lot of movement and analysis. Sometimes I'll jump from section to section, trying to isolate things and block everything else out (kind of like the PS2 game Frequency where you play one part when switch to another one), other times I’ll focus on the entire sound it was created as one big chunk, and other times it'll be completely different, like focusing on rhyming sounds or passages, or the level of different things and just how things sound, like trying to hear all the detail. The fact that the soundstage is small and closed makes this harder. And then throw the glasses issue in. If I am to be honest, I have to give them low ratings given these experiences. I still have them, and only use them without glasses, but unless I use them a lot, things don't sound "right" or natural to me. They are quite unforgiving.[/size][/size]
Good review. May I suggest an headphone that you might like that's not too much more? The Soundmagic HP100. I think this might be up your alley. I'm very pleased with them. They have a pretty good soundstage for being closedperhapsm its just that they image well with everythingbeing in its own spot with space in between its unlike my V Moda M80s which aren't bad but are congested in comparison. They also have bass that goes to sub levels yet theres zero mid bass hump leaving the mids very clear. Mids are detailed and neither forward or recessed but may lack a bit of body if you prefer a warm signature. The treble is also very well represented being very sparkly but never harsh. That's whats great about these, they really have perfected a headphone that isn't warm but detailed yet not boring or harsh. Read the reviews but this set really surprised me with the amount of air and detail while still able to produce thunderous bass when called for.
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Thanks for the feedback! I haven't actually heard of those. I sold the KRKs, but never replaced them. I did however follow some other alternatives around that time, but then kind of left the site [good thing for email notifications on comments]. At the time I was looking at Denon AH-D600 (come to find out, it might not be balanced at all), Brainwavz HM5, and Hifiman HE-400. I'll totally add the Soundmagic HP100 to the list. I like getting new leads.
Oh ya, the Soundmagics are very comfortable too with large round memory foam in pleather, but good soft pleather. They may not look the greatest style wise though. They also clamp just enough to not rely on the headband to stay in position. The other reviews here on the HP 100s are quite positive and accurate from my experiance. They are definately good for their price. Glasses may cause leakage/less bass but these aren;t affected by this as others. They are also a bit power hungry for 32 Ohm impedance because of relatively low sensitivity but can be powered by portables, they just need to be nearly maxed to get the volumes I like which tends to be loud. Best of luck on the quest.


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