Rated as "superb" by a well-known German HiFi magazine, but pretty much ignored on Head-Fi. So what's the deal with the $50 Koss KDX200?
I stumbled across the Koss KDX200 purely by chance. German HiFi magazine "STEREO" had rated these budget IEMs as "superb" in their 08/11 edition and one unsuspecting buyer on Amazon ended up being bitterly disappointed, saying he felt cheated and fooled. (Curiously enough he didn't disclose anything about what had actually bothered him.) What's more, these phones seemed to have been available for quite some time and pretty much gone unnoticed on Head-Fi. I was hooked. This was the stuff that "audiophile detective stories" are made of. I set out to go to the bottom of things...
Single dynamic driver in aluminum housing
Frequency response: 15Hz to 20kHz
Distortion: < 1.0%
Like all Koss phones, these come with a lifetime warranty.
€60 from Amazon Italy. (A rip-off compared to the US price, but no hassle with custom duties and easier to claim warranty)
In the Box
You get the phones, a small plastic pouch and the usual 3 sizes of silicone tips. The latter have better quality than a lot of stock tips I've seen and are nicely soft and rubbery.
Design and build quality
The KDX200 seem to be very well built for the price, with sturdy aluminum housings and proper strain reliefs. The cloth cords are rather thin and prone to kinking, but at least the material appears to be of pretty good quality. There's no chin slider, but you can kinda make up for that by twisting the upper cords before you put the earpieces on.
Due to the housing design these can be either worn downwards or over the ear. Microphonics are about average when worn downwards and almost non-existent when worn over-ear.
These phones include a free eyesight test in the form of microscopic L/R markers on their stems. I ended up marking the cords with a highlighter.
Fit and Isolation
Fit is a breeze, since the earpieces are easily handled by their stem and the stock tips provide sufficient flexibility and friction for a good seal. I can't think of any potential fit issues, except that the strain reliefs might be a bit long for over-ear with very small ears. Once fitted the KDX200 provide decent isolation, not as good as the best isolating armature based IEMs, but better than the vented and open back dynamics I've heard.
Two remarks regarding the tips, first they're a bit difficult to slide onto the nozzle, but turning them inside out and putting them on your fingertip makes things much easier. Second, the Koss stock tips have notably shorter stems than most silicon tips I've seen, which make their large openings sit almost flush with the nozzle. This design choice is part of the IEM's tuning and the use of third party tips with longer stems will probably affect the sound more than on other phones.
Disclaimer/words of caution: I don't hear much above 16kHz, so take my comments about highs with a grain of salt.
I've had the KDX200 for about a week now and they've been played for roughly 100 hours. I haven't noticed any significant burn-in effects apart from a moderate smoothing out during the first day of use. All music has been auditioned unequalized straight out of my Cowon i9 and Samsung R0.
Here are some brief listening notes:
Brasstronaut - Six Toes
Love this track for its highly transparent recording quality ... wow, drums and bass are strong, but well controlled and without the common boominess of that price range. Mids remain clear and seemingly unaffected by bass ... I'm impressed. Very good dynamics!
Cassandra Wilson - Closer To You
This song includes deep bass notes that are almost inaudible with some of my armature based IEMs, but not so with the Koss ... these have amazing extension!! Again, bass steers well clear of the midrange. Vocals sound natural and slightly forward, without getting too close. Nicely done, no major complaints.
Dave Holland Quintett - Metamorphos
This live recording is great for testing bass quality/detail and soundstage/positioning. The KDX200 pass both tests with flying colors. Even though bass is clearly enhanced over the rest of the frequency range, it doesn't fall far short of the control and detail of much pricier IEMs. Moreover, its punch is fairly well distributed across the whole bass range, so there's no midbass hump or such. Soundstaging is also very good, with realistic dimensions and forward projection and even though they lack the ambience of vented IEMs, there's a nice airiness to the KDX200's presentation that sets them apart from the more boxed-in feel of many other closed IEMs.
Diana Krall - Too Marvelous For Words
Well, for a soft and romatic song like this bass presence is a bit too much for my taste. But keep in mind that I'm a fan of the leaner sound signature of an e-Q7 or EX600. Folks who prefer to play those phones from a digiZoid ZO would be pleased with the KDX200, no doubt. That said, there's no mids bleed to speak of and Diana Krall's vocal timbre stays pretty unaffected and realistic. Slightly forward and natural mids convey a nice intimacy with this song and the delicate, laid-back cymbals are exquisitely detailed and refined for a DD based IEM at this price.
Gossip - Heavy Cross
A straightforward rock song with edgy guitar and energetic vocals. The Koss sound dynamic and aggressive, but bass levels get too high and the phones start to compress and struggle to maintain control. Voice and percussion are still crisp and quite clear, but the overpowering bass simply ruins the track for me. A quick check with the IE8 shows that bass gain is indeed insane with this track, but the Senns manage to handle that much better.
Gustav Mahler - Symphony #2 (Birmingham Sympony Orchestra, S. Rattle)
The acid test with large orchestra, it doesn't get more fulminant than this ... first thing that comes to mind, that's good soundstage for a closed phone. No doubt the airy highs contribute to the presentation ... somehow reminiscent of the Cyclone PR2, but it's been a while since I heard these ... just listen to these flutes and triangles! ... treble is special on the KDX200 and way better than their price tag would suggest. Dynamics are also excellent and lend great depth to the orchestra. Timbre of instruments is surprisingly natural, despite the (too) strong low end of these phones ... I honestly wouldn't have expected for these to sound good with classical, but I was wrong.
Markus Schulz - Mainstage / Fly To Colors
Let's see how the KDX200 fare with trance, courtesy of shigzeo (sadly miss his poetic reviews) ... "Mainstage": how much deep bass rumble do you need, lol ... these must reach down to 20Hz without breaking a sweat ... "Fly to Colors": impressive pounding down low, while things stay nicely clear and crisp from the mids upwards, I've rarely heard such impactful bass combined with a crisp and clear upper range that isn't sharp or thin. Speed is about average, these are DDs after all ... even though these fair pretty well, I'd prefer a less bass heavy BA/MA based phone with this track.
Origin - The Aftermath
The ultimate speed and separation test, to sort the wheat from the chaff in technical ability, and sure enough here's where the difference between the $50 KDX200 and top tier IEMs shows the most. Their drivers aren't fast enough to keep up with this track's insane pace and the result is rather messy. A short A/B with my IE8 clearly shows that the Senns manage to keep up better, even though they in turn fall short of comparable BAs. Let's face it: the Koss are just not made for this kind of stuff, period.
Stacey Kent - Ice Hotel / So Many Stars
This is a borderline sibilant recording, so any phone that hasn't subdued treble will sound sibilant with it. As expected the KDX200 show some slight sibilance, but their treble tuning is on the forgiving side ... still, those brushed cymbals have impressive detail and apart from (once again) slightly too much bass presence the phones sound surprisingly transparent, with pleasant vocals and overall excellent refinement for the price range.
Vaughan Williams - A Sea Symphony (Atlanta Symphony Orchestra, R. Spano)
Let's conclude with one of my very favorite classical pieces ... the final movement's choral passages are more or less my goosebump benchmark, a test how well the phones can carry atmosphere and emotion. Yes, I know that's highly subjective and unprofessional, but hey, it's my review ... btw, this has proven to be more accurate than anything else in predicting which phones will remain among my favorites after prolonged use. As for the KDX200, they fare pretty well, but fall clearly short of the best. There's nothing glaringly wrong with their presentation, but I think I just happen to prefer a leaner and brighter tuning and the even more spacious soundstage of open/vented IEMs. But to put things into perspective, the Koss perform about on par with my UERMs in the "goosebump test" (though of course not in technical ability).
Final thoughts / Conclusion
Well, I know I'm probably pretty spoilt by having heard so many top-tier IEMs and being fortunate enough to afford one of the very best customs out there. And I'll freely admit that I'm no more on top of things when it comes to the plethora of current budget phones and the value they represent. But I think I still know good sound for the money when I hear it and these Koss KDX200 may well turn out to be the best bang for buck IEMs I've ever heard.
Granted, they don't exactly match my preferred signature that favors a slightly leaner sound and their budget-class dynamic drivers can't quite keep up with much more expensive phones in speed and separation. But hey, don't forget we're talking about a pair of $50 IEMs. For that you get sturdy aluminum housings, great quality stock tips, decent isolation, deep extended and well controlled bass without hump or midrange bleed, natural mids with good presence (but not too much in-your-face), nicely detailed/refined and forgiving treble, realistic timbre and soundstage and last not least a lifetime warranty.
I'll keep it short, the Panasonic HJE900 were a great budget phone for about $100 and imo these don't fall far short (if at all) in refinement, plus they're overall better balanced for half the price. Highly recommended, if you're looking for a reasonably neutral monitor-like sound with slightly forward mids and added deep bass boost. Stay clear of the KDX200 if you listen to extremely loud and/or bassy music (cause they may compress and loose control) or to music that requires ultimate speed (cause they may fail to keep up).
As for the solution of my "audiophile detective story", that Amazon buyer who felt "cheated and fooled" - I can only suspect that he belonged to one of the mentioned groups that should better stay clear of these phones. For everybody else, the KDX200 should provide nothing less than an excellent listening experience for the money.
+ good build quality
+ lifetime warranty
+ excellent sound quality for the price
+ monitor-like balance with moderate bass boost
+ decent isolation
+ good soundstage
+ realistic timbre
- bass may be too much with some music
- lacks speed for extremely fast stuff (e.g. death metal)
Edited by james444 - 12/10/11 at 12:14pm