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A Review On: KRK KNS8400 Studio Headphones

KRK KNS8400 Studio Headphones

Rated # 173 in Over-Ear
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Pros: Replaceable cord, very detailed, lightweight, many wearable positions

Cons: Incompatible with glasses, small soundstage, bass light

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.



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).



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.


Build Quality

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.



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.


Sound Isolation

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.



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?)



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.



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.



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.



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.



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.


Fatal Flaw

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.



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 (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).



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.


Hey, that was a pretty interesting and well written review! Nice to read your 'virgin' impressions on a headphone versus your normal listening experiences with speakers.
I wonder what you'd think of an IEM like the Sony EX600.
I have no idea since I've never used IEMs or even flat earbuds. Do you think they sound even more compact than closed headphones? They sit deeper in the ear (but the other hand have a 180 degree speaker). I'd probably be obsessing about how they fit fit and keeping them clean, like using oil treatments on my ear 24/7 to make sure no earwax ends up in them.
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.
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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