So a fellow Head-fier PM'd me asking me to compare the RE262 and W4 and I got a little carried away in my response and it turned out to be very long (as well as me including the SM3 in the response). I felt it'd be good to share my thoughts regarding these 3 IEMs with the rest of the Head-fi community.
The RE262 is a very interesting IEM and is still among the top 3 IEMs I've ever heard, the other 2 being the SM3 and the W4 (with the e-Q5/e-Q7 following VERY close behind). Among these 3, I don't think I could really rank any of them in any order since they all do different things so well.
The RE262 definitely has the most intimate, lush, and sweet midrange of the 3 and has a warm signature while still maintaining clarity. The highs are indeed present and extend well, but the mids are indeed more forward, giving what seems to be a false sense of the highs not being present enough. The highs do have sparkle and energy, but nowhere near CK10 amounts. The sound is very musical and I found it very natural and cohesive. The bass is very tight and extends deep, the bass definitely has more impact than any other previous head-direct/hifiman IEM. Sometime I did feel I wanted just a tad more bass quantity and impact though. The sound is overall very smooth.
The SM3 is a very enveloping IEM with a very thick sound that draws you in and gets your feet tapping. It's very musical and can make you nod your head to the beat on almost any song. There is not as much airiness as the RE262, but it still does maintain clarity, though the sound is definitely thicker than the RE262. The mids are forward, lush, and sweet, but since they are thicker than the RE262, they give a different presentation. The SM3 definitely hits harder than the RE262 in terms of bass and has more quantity. It really gets your head bobbing on particular tracks. The highs on the SM3 are not as prominent as the mids and bass, but I personally found it very much present and with enough sparkle and energy (the tips are very important in this regard). Some tips with smaller openings will muffle the highs and I felt that the Shure Olives are the best tips by far. Sound is overall very smooth, with the highs maybe being a little less smooth (sharp) than the bass and mids.
The W4 is a peculiar IEM. It does almost everything right and it is hard to find fault with it. Every frequency (bass, mids, highs) are in the right place and it doesn't seem like there is a particular bias in regards to the frequency response. In comparison, the RE262 is definitely mid biased, while the SM3 is definitely mids and bass biased (but this does not mean that the highs are recessed or lacking in any way). On the W4, I could not discern which particular frequency was more "forward" in comparison with the others. There is not much coloration and it presents music in its purest form. However, don't think that this means that the W4 is boring, it is not boring at all. It really does depend on the song that you are playing through them and I feel the W4 are true to the reproduction of the sound through and through. Songs that are meant to be fun and exciting will sound fun an exciting, while songs that are meant to sound more mellow will sound more mellow. It's a very peculiar trait since I found that IEMs such as the SM3 and RE262 could make even "mellow" songs sound more exciting (which is not necessarily a bad thing and many times I miss them for this).
This being said, the W4 has a hint of warmness and maintains clarity through the whole spectrum. There is no "veil" that some other IEMs suffer from when they are warm. The bass hits somewhere inbetween the SM3 and RE262 in terms of quantity, and has a very nice and natural texture, it is very punchy with nice impact as well. While not as present as the SM3, the bass can be called up in bass heavy songs such as hip-hop and I never felt like I was thirsting for more bass. The mids are not as thick or forward as the SM3 or RE262, but are still very smooth and liquid. They can be very lush and sweet if the particular song calls for it, and more neutral when the song doesn't call for it (again, this is that peculiar trait). The highs are very smooth as well and definitely smoothed out from the ear-piercing W3 peaks. The extension is great and I felt the highs were in the perfect place. Sometimes on the SM3 I felt I wanted a little more treble presence, on the W4 this rarely happens. The W4 has the ability to deliver energy and sparkle in the highs when necessary (think cymbals and guitars in rock).
Though the W4 can be fun and exciting when the song calls for it, I don't think it can ever reach the level of excitement that the SM3 gives these songs. Sometimes when I'm in the mood for a very forward and aggressive sound, the W4 falls short of delivering this to me. However, I have a tendency to lean towards forward and aggressive signatures and I love the Grado sound signature so others may never see this as a shortcoming. If I really had to choose which frequency was more forward, I would have to say that the mids come to mind. However, I'm a sucker for the extremely lush, intimate, and sweet mids ala the RE262 and SM3 (moreso the RE262) so sometimes the more neutral and natural presentation of the W4 leaves me wanting some more coloration (again this is a personal preference of mine so others may not find this as an issue). I do have to say though that for classical music, the W4 blows every IEM I've heard out of the water. While the W4 is a perfect all-rounder, it is a beast when it comes to classical music and I don't think I've ever heard recorded classical music sound this good through any IEM.
Edited by EraserXIV - 3/14/11 at 1:55pm