KRK KNS-6400 Review - Impressive $99 Giant Killer
Sep 16, 2011 at 4:59 PM Post #166 of 235
Hey Tyll, have you stated which you prefer out of the two KRK's, subjectively, given you've had time to compare the two?  My personal experience is, kind of, in conflict with your measurements.
 
I didn't really listen to coloration or naturalness, as I've stated here and there many times, but actually how well notes were distinct from each other. I don't think this can be heard that well with tonal pop, folk or other "easy-going" genres, for instance, but is very clear with, what I've come to emphasize a bit later, modal jazz or fusion. It's easier to tell about headphone's capabilities in this sense, when you can't "guess" what's coming next ie. what the tonic defines and whatnot. 
 
Some of my views here: http://www.head-fi.org/t/570501/the-krk-kns-8400-you-can-have-it-all
 
In other words, the 8400 are more musical to me, but maybe not that natural (in sound) to many. The difference in what I stated above, which to me is "musical accuracy", was big. Any views from anyone? 
 
I'm also really bad at taking the sound out of context (music) and categorize aspects of sound, like treble, mids and bass. So if anyone comments (and I hope people do!), could you make references to music and instruments instead of other headphones or free-of-context adjectives? This would help me out a lot! 
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 Thanks.
 
Sep 17, 2011 at 11:45 AM Post #167 of 235
Sorry, I've only measured them and had a cursory listen.  I may get around to a review eventually, but the plate is pretty full at the moment.
 
Sep 17, 2011 at 4:39 PM Post #168 of 235
Ok, no worries. Thanks for the reply!
 
Anyone else?
 
Sep 20, 2011 at 2:40 PM Post #169 of 235
Even though the headphones sound, incredibly clear and crisp i guess i don't find them loud enough for me...i find them using at 100% volume all the time...is it cause i am powering through a laptop ? i doubt so...
 
I was just hoping these headphones would be louder....
 
Do you guys have any suggestions other than getting an amp ?
 
Sep 20, 2011 at 2:59 PM Post #171 of 235
That's probably the problem. One funny thing I noticed is that on my Ipod Touch I have to crank them to nearly 90%!! The Ipod Touch can drive some hard to drive headphones quite loud (doesn't mean they'll sound good of course). Other than an amp there's not much to do I think.
 
I know you said no amp, but even a new $20 E5 would help, but you shouldn't have to do this since the KRKs aren't too hard to drive..
 
I'm sure someone has some better ideas..
 
Quote:
Even though the headphones sound, incredibly clear and crisp i guess i don't find them loud enough for me...i find them using at 100% volume all the time...is it cause i am powering through a laptop ? i doubt so...
 
I was just hoping these headphones would be louder....
 
Do you guys have any suggestions other than getting an amp ?



 
 
Sep 21, 2011 at 12:54 PM Post #172 of 235
[size=10pt]You do need a near-zero-ohm headphone jack to drive this headphone properly. No doubt about that. If you think there is precision overall and deep lows with just any jack, you haven’t yet heard even half what this is capable of in those regards. And you're right, they're not as sensitive as the specs say. Still, with a proper jack and the inherent extension and neutrality (measured, at least), once you have a good amp they do well at low volumes and don't need to be cranked. So once you drive them right, you may find yourself no longer needing extra voltage. The irony! [/size]
 
[size=10pt]There does sound to be like a slight phasey quality to the otherwise flat lower midrange and all the bass that's hard to put my finger on. Combined with the measured mid-bass dip in the 60-70hz range of just a few dB, and I think the combination of them might be responsible for the impression at times that there's a lack of bass. It's there, but it's the equivalent of de-hyping the sound. You know some headphones have bumps in those areas to fake emphasis for the whole band; this does the exact opposite. It’s de-emphasizing. There's no lack of attack, as the initial upper bass strike (and midrange is of course also part of that) is there. And there's no lack of decay for the lower bass in particular, but I can see how the mid-bass oomph is perceived as reduced. It's kind of the opposite of a lot of closed headphones. The closest might be the HD280, which has less bright mid treble and less extension in the upper treble, and its treble is fizzy and less controlled. The 6400 definitely has more energy on the top end, and the upper midrange roll-off is delayed until 3khz rather than starting at a more pleasing 1khz. Even the 2khz beginning of the Sennheiser’s roll off didn’t cause a sense of exaggeration there. So you could say in addition to the KRK's 2-3dB dip in the mid-bass, there's also a 2-3dB relative rise compared to a lot of warmer sounding headphones in the 2-3khz range. What's strange is how small these frequency imbalances are, yet for music listening tends to sound larger as they are the primary "wow factor" and tonal range, let's say, for the low end and the region for female vocals, respectively. [/size]
 
[size=10pt]Back to HD280: it's got no lack of mid bass, but its upper bass kick is reduced. So you get oomph, decay, and deep bass that isn't lacking much (KRK is still deeper), even if there's a total lack of upper bass attack. You get subwoofer-like action on the Sennheiser, but combined with a lack of beat attack, a somewhat imbalanced or even murky middle-midrange, and far less controlled and more fizzy (though tamer) highs. Even though the KRK vastly excels at studio-style monitoring with its extremely extended response and precision in the mids & highs, and the HD280 has that resonance problem with the driver housing the guy at Rat Sound found, I think many people would prefer the HD280 for music listening. It's less bright. It sounds more like a sub. And its dips or peaks are not in as-sensitive-of regions. The housing resonance and fizzy character to the treble are the only things really holding the Senn back from getting a recommendation. [/size]
 
[size=10pt]I'm wondering if a full spectrum phase distortion test like Ryumatsuba does might show what we are hearing that lends itself to that oddly hollow, phasey thing going on from 500hz down on the KRK. I'm also curious if a very warm euphonic tube amp might improve the KRK's sound. Besides the often warmer tone, tubes sometimes misalign low frequency phasing, so perhaps it could correct it back in the other direction. [/size]
 
[size=10pt]Then again, I could be completely wrong. We could be hearing nothing more than a combination of the mid-bass dip and upper-midrange elevation with a more accurate rendition of extreme highs and phase-accurate bass and lower-mid reverb. We could be mostly hearing bad artificial reverb and poor production choices along with a more accurate response. Goa trance in particular doesn’t sound weird to me with the KRK, and the headphone at lower volume is unique for one in the price range for its extreme extension and fairly neutral response.[/size]
 
[size=10pt]The cord completely sucks, though. There’s no getting around that. And the driver housing itself doesn’t inspire confidence in reducing the microphonics of the cord. I think this is where we start bringing up the benefits of wood :wink:[/size]
 
Sep 21, 2011 at 1:13 PM Post #173 of 235
Kinda reminds me of Audio Technica cables: Very fiddly and microphonic... Could be better. 
 
Edit: At least it's interchangeable. 
 
Sep 21, 2011 at 1:28 PM Post #174 of 235
Actually, according to http://www.innerfidelity.com/images/KRKKNS6400.pdf, the KNS 6400 is about 1 dB more sensitive than what is in specs. But that is still not a great sensitivity anyway. Also, the measurement may or may not be accurate.
 
The notch around 65 Hz is quite audible if I try to reproduce it with a parametric equalizer, it is also deeper than just a couple of dBs. From the "raw" graphs it can also be seen that the bass response of this headphone is quite sensitive to the positioning, it can be much worse than what is shown on the averaged graph if the sealing is not perfect. It also looks like the 65 Hz notch gets relatively deeper with a better placement.
 
Quote:
Originally Posted by Reticuli2 /img/forum/go_quote.gif
[size=10pt]And you're right, they're not as sensitive as the specs say.[/size]
 

[size=10pt]Combined with the measured mid-bass dip in the 60-70hz range of just a few dB, and I think the combination of them might be responsible for the impression at times that there's a lack of bass.[/size]
 
 

 
Sep 21, 2011 at 2:31 PM Post #175 of 235
I'm still wondering how Tyll got optimal positioning.  Would deeper or memory foam cushions improve them?
 
Edit: Midnight 9/22/2011
 
Got done watching Ninja Assassin on Bluray on that Denon receiver.  First viewing.  HDMI sound.  Definitely a synergy with the 6400 for sure with that DAC, that jack, and DTS HD in direct.  I know a Numark PPD9000 I have in storage has a sort of slight S-shaped frequency response with a mid-bass bump and upper-mid dip.  I wonder if it's something like that going on with the Denon or an impedance matching that is not near-zero-ohm that's doing the trick.  Neither the Emu 0204 at 22ohms nor the Fiio E7 at under 1ohm makes it sound like that.  Maybe DTS's classic mid-bass boost is part of it? 
 
Oct 11, 2011 at 5:33 AM Post #177 of 235
Timbre is such an abstract term and falls under subjectivity... I'm not that familiar with most of the recordings in my possession, but the 8400 do have a great way of making instruments sound rather "real", to me, and more importantly plays everything to the note. Bass is mostly articulate, but the kick drum is sometimes not distinct. They lack the bass distortion many seem to like, at least they sound like they do. There's nothing boomy or annoying about them. 
 
Can you explicit on what you mean by timbre? Maybe I could help better. The 8400 do everything much better and accurately, including a sense of realism to instruments in the mid-range, than the 6400, of which I only have 30 minutes of experience, however.
 
What irritates about the 8400, is the treble. It is louder than one would like, at least with instrumental music. If you want to discern the rest, you have to boost up the volume a bit which in return makes it slightly fatiguing. 
 
Oct 11, 2011 at 9:27 AM Post #178 of 235
True.. timbre is really difficult to put into words. It's really the combination of many factors such as attack, decay and tonality. Headphones that decay too fast for example will make certain instruments sound unreal, for example like the strings on the guitar that stop vibrating too quickly. But more importantly, the tone which can't be described in words. My AD900 whilst is very clear and transparent does not sound quite right to me. Instruments sound a bit off. The guitars don't sound what I'd expect if I pick a real one up and play myself. It's like there's some minor distortion somewhere. Really sorry I can't find the right words. It just doesn't sound quite real (enough).
 
But I'm a bit of an OCD when it comes to timbre. Most people are happy to live with coloration which may make music more enjoyable to them. Others don't really care (or notice) so much about it so they look at me puzzled when I keep repeating about tonality.
 
Oct 11, 2011 at 11:59 AM Post #179 of 235


Quote:
True.. timbre is really difficult to put into words. It's really the combination of many factors such as attack, decay and tonality. Headphones that decay too fast for example will make certain instruments sound unreal, for example like the strings on the guitar that stop vibrating too quickly. But more importantly, the tone which can't be described in words. My AD900 whilst is very clear and transparent does not sound quite right to me. Instruments sound a bit off. The guitars don't sound what I'd expect if I pick a real one up and play myself. It's like there's some minor distortion somewhere. Really sorry I can't find the right words. It just doesn't sound quite real (enough).
 
But I'm a bit of an OCD when it comes to timbre. Most people are happy to live with coloration which may make music more enjoyable to them. Others don't really care (or notice) so much about it so they look at me puzzled when I keep repeating about tonality.


What if the vibration is on the recording and the headphone is not able to produce it ie. is not fast enough? What is ideal exactly? I don't think a headphone should stay "ringing" for a sense of false realism. 
 
These are very detailed and I find the tone with many instruments is spot on. They don't sugarcoat anything, but notes are easy to follow and they lack coloration that would make a headphone boring in the long term. Musicality in its finest. By that I mean, that it's accurate enough but not harsh, like many studio gear that's meant to pinpoint flaws in recordings. That said, the treble is still a bit too hot.
 
Not sure if it's my head or not, but I've been listening to the 8400 for two or three hours today and I think the bass response is much more articulate than what it used to be. I go back to recordings I tried when it wasn't quite spot on and more stuff is not distinguishable. Could this be burn-in or that my listening habits have just adjusted? Maybe should take this particular piece of conversation to the 8400 thread 
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Edit: I have to add that I can't go back to the K272HD anymore. A triumph :) 
 
Oct 11, 2011 at 1:37 PM Post #180 of 235
I do think I hear a subtle, low-level midrange distortion (or maybe it's those distortion spikes on Tyll's measurements in the lower highs?) on the 6400 that lends sound a mild, faint mid-range grit.  I will see if it goes away with the leaner, supposedly cleaner E6 or a cmoy compared to the E7.  My O2 is still a few months off.  The Emu 0204 isn't quite the right amp to be using with the KRK, but I think I hear it with that, too.  It's not awful, but I don't hear this subtle distortion on the Fostex, modded HD25, Sporta Pro, or ER4S.  It seems not present in the recording.  Anyone else notice it?
 

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