I have to be perfectly honest and admit I wasn't going to post the following impressions, but I've been persuaded by someone who suggested I should.
Please note this is not a review.
I've only A/B'd the K3003s against my ES3X & EX1000. My sources being my 4G Touch and MacBook Pro. The combo with the Touch is excellent, or so my ears tell me. Same goes for the MacBook Pro, just brilliant synergy all round. I've yet to try the K3003s with my (still unsold) 64GB Sony A857, but I'm in no hurry to do so. That said, The AKGs are slightly easier to drive than the EX1000s, and the ES3Xs are more sensitive than the other two.
I found the K3003 somewhere in between both the Westones & Sonys. However, overall they are a little closer sounding to the EX1000s, even when all 3 frequencies are rendered somewhat differently.
The mid-bass on the AKGs has been done so right!! Finally someone gets it right with a perfect balance of sub-bass, mid-bass, still allowing for a perfectly smooth and accurate midrange - absolutely superb.
I've always found the ES3X's mids to be their strong suit and my reference to judge the midrange in other phones. The K3003's mids sound a little more life-like, though. My guess is not just the different way the ES3X & K3003 have been tuned, but the more accurate blending of frequencies on the K3003s, with a more coherent presentation, may be giving me that little extra sense of naturalness in the midrange.
High frequencies are also the best I've heard, never harsh, shrill, but never recessed, the clarity is quite remarkable and very natural.
This is the very first time one of my all-time favourite albums, Robert Fripp's Exposure, sounds absolutely right - at last! No other IEM or full-sized headphone - only proper speakers - had ever convinced me when listening to this particular album, some got close, but never really quite got there. Starless, the studio version, off King Crimson's Red album from the latest 40th Anniversary series remasters sounds simply incredible, the percussion sounds stunningly good and so lifelike, mids are to die for, and bass sounds also fantastic, tight, well-rounded, note weight just like it should be, and never overpowering, thin, boomy or sloppy.
(Bartok & Beethoven) string quartets, and the rendering of strings in general, is quite simply breathtaking - I was honestly a bit surprised to hear strings sounding so very right. Timbre on the AKGs is literally something else with every instrument and/or voice thrown at them. Good recordings shine, and even not so good ones sound better than with any other phone I've heard. Acoustic guitar has never sounded this good, either.
On string quartets & quintets and chamber music, in general, however, the AKGs do better than anything else I've ever heard, and where the EX1000 might at times sound slightly thin with certain recordings (and not so with others), the K3003s always seem to get it right, or never make certain recordings leave you with a sense that something's not quite right.
The EX1000 is indeed very impressive with orchestral music, and certainly the best I had heard with this type of music. The Sonys really excel with (very) good recordings (of any genre). I was already very impressed by the EX1000s with orchestral music, where the ES3Xs simply couldn't compete. However, I've been most impressed by how the K3003s render orchestral works, or at least the orchestral works I've so far thrown at them. There may be a couple of recordings where the Sonys can almost practically match the K3003's performance & realism, though, yet very subtle details in the mids & refinement of high frequencies still give the AKGs the upper hand
Detail retrieval is EXCELLENT, never distracting, all instruments clearly defined, yet blending wonderfully, absolutely seamless transitions along the whole freq range - remarkable. these IEMs are truly reference, or at least that's how I perceive them.
Soundstage depth and width strike a wonderful balance, where nothing feels constricted, boxed in or artificially boosted/created. Orchestral music sounds phenomenal - Sibelius' Violin Concerto in D Minor, Mozart's Requiem, Bach's Mass on B Minor, Stravinsky's Rite of Spring, Elgar's Cello Concerto in E Minor, or Beethoven's 4th Piano Concerto never sounded quite like this.
Unlike the CKM99s, which are very good at lower volumes but quite frankly suck at higher ones (I only use them in bed late at night and often at very low volumes), and the EX1000 not being convincing enough at lower volumes with some kinds of music, the AKGs excel at any volume level, much like my ES3Xs, which are very solid at any volume level, but at lower ones the AKGs get that extra bit of richness, musicality and sense of realism.
As for isolation, I haven't got any Westone/Shure universals with me anymore, I had a chance to test the K3003s during a flight along with my ES3Xs. My customs, of course, provided better isolation and made the journey more bearable, but the AKGs were not all that bad, they reminded me of times I used my UM3Xs during flights, hence why I said the AKGs were not that far. Still, I remember my W4s back in April blocking more outside noise than the AKGs and, of course the W4s and UM3Xs offer very similar levels of isolation.
)
