These are my initial impressions after A/B'ing both EX600 & EX1000, both with EX600 cables.
But before I get to that, I'll talk about the cables: I have to say I have not heard any sonic differences between the EX600 & the real EX1000 cable - none whatsoever. Both were only tested on my EX1000 IEM (didn't want to spend time trying both cables on the EX600).
The EX1000 cable is exactly as I remembered it from the loaner set I got back in April. The cable is thicker but VERY light and somehow less prone to tangling and a little more flexible than the EX600 cable. Also, the type of plastic used on the EX1000 cable has quite a different feel to it and it's a little less microphonic even than the EX600 cable, which already has virtually no microphonics. The overall quality is better - I was rather disappointed when I saw the American EX1000 not only came with just one single cable but, more importantly, that Sony had decided to use the lower-quality EX600 cable for an IEM that is officially worth $300 more. However, as noted elsewhere, the strain relief on the EX600 cable may prove better in the long run. As it is right now I'm quite happy I have the original EX1000 cable as it feels stronger, looks smarter and matches the better build quality of the EX1000 earphone.
Right, now to the sonic differences between the EX1000 & EX600:
Unlike a couple of people who have reported harsh treble on the EX600s right out of the box, I have to say I didn't find that to be the case with my set. I also didn't notice a difference with my EX1000 out of the box or even after a few weeks, nor did I notice a difference between my fresh EX1000 pair and (from memory) the EX1000 loaner set I got 2 months ago, of which the owner also reported not hearing a difference after burn-in. That said, after a quick 20-minute listening session with the EX600, I left them burning-in for 6 hours with pink noise (just in case) as I always do with all my phones.
The EX600 & EX1000 share the same sound sig, absolutely no question about that. Much like the EX1000s, the EX600s do very well with any music genre and any differences in SQ I attribute more to the quality of a particular recording and/or mastering rather than to specific music genres.
Generally speaking the EX1000s sound to me as if I was listening to a higher bitrate file, ie the same sound from same source and phone but with improved SQ (on the EX1000s). I liken it more or less to going from 128 kbps to 192/256 kbps, not really from 192 to 256 where I personally can't (if ever) hear a real difference in SQ. I know there are qute a few people out there who claim they can hear all these differences between 192, 256, 320 kbps & lossless files. I remain very sceptical about the whole "you've got to use lossless files" mantra often seen on HF and, gladly, I've confirmed what my ears hear after also reading about a couple of proper tests carried out by some audio experts - this 'debate' reminds me of a couple of Stradivarius vs some other high-quality violin tests that have been conducted. But I digress.
-- Anyway, on a few tracks the low-end on the EX1000, specially the lower, sub-bass type of bass, has a little more body, slightly more rumble & better definition. On pieces with less deep bass, the low-end still sounded a little more defined & refined.
-- The treble, though definitely not harsh, doesn't sound as smooth as on the EX1000s, the difference being quite small and this can be more OR less evident depending on the piece of music being tested.
-- I had more trouble finding differences between the mid-range as differences were more evident at both ends of the spectrum, but at times I could barely hear the mids having a tad more definition/clarity and 'roundness'.
-- Soundstage: I hear no real difference between both phones, although the slightly better rendering of low frequencies may contribute to a slightly more expansive feel - this is very subtle.
I'd like to point out that all these differences, for the most part, were rather subtle and not immediately apparent but they became more evident/easier to detect at higher volumes, when both IEMs were being put to the test to see if they were able to perform so well. Again, at times it felt like when comparing different bitrate files, sometimes these differences were more audible than others also depending on the track being used. I have to say the EX1000 was always effortless, but the EX600 was always very close.
So, would I recommend to people the EX1000 over the EX600? Yes, if they're prepared to pay a premium for a small increment in SQ and better build quality - I personally fall into this category, so I'll definitely be keeping my EX1000s. BUT, I'd certainly recommend the EX600s to most people as it is indeed an incredibly good phone, specially considering its price. Paying $175-$200 for the EX600 will make some people think, SPECIALLY here on HF, they're not getting high-end SQ - well, they would most definitely be wrong. The EX600 is a truly excellent phone and, as I suspected, I now consider it one of the very best bang-for-the-buck phones available at present (for those in search of top SQ). I have no reservations in saying that the EX600 is a true top-tier universal IEM, up there with the W4, UM3X, TF10, CK100 & IE8 (the best top-tier IEMs I've heard apart from the EX1000).
