I haven't posted in ages...but since I wanted to occupy myself with something, I figured I'd post something about the Westone 4. I don't really know how to describe sound so I won't really go in depth, but feel free to ask me anything. Just a little background, I have been using the W4 ~5 days a week for at least 3 hours a day since August 2011. Since I don't really know how to review, I will just post random songs I listen to and explain what I like about the presentation. All the listening is done with iTunes -> Audinst MX1 DAC/Amp, using the amp section of the amp for my earphones. I am also using the Earportz tips, Size L. Although I it might seem like I'm describing the song itself, I'm describing how it sounds through the W4.
Boom Jinx & Andrew Bayer - To The Six (Above & Beyond Anjunabeats Vol. 7)
The synth noises are very accurate with the W4. I can hear a lot of the detail in the synth noises throughout the song. They don't spike like with other earphones and become sibilant with the W4. The separation is also good; there doesn't seem to be any mushing of the synth. Each note can be differentiated and overall it's pleasant. The bass hits, but it never muddy. It has a lot of weight and feel and as a basshead, it is perfect for me. The midbass doesn't seem to be interfering with the other aspects of the song. The soundstage is pretty good with the W4. It's definitely not super wide but it takes it a little beyond my ears and I don't feel congested listening to the song.
Nero - My Eyes (Welcome Reality)
I apologize but the Youtube version in the link is sped up...but at least there's a sample for people who don't know of it. I like this song because of the strong repeated bassline and the vocals. They're not revolutionary, they're not that good, but it's what I enjoy. Again, the bass is astounding. I used to own a pair of Ultrasone Pro900, and although the bass in the W4 isn't as strong, it's still surprising. The vocals in the song come up pretty clear even when the synth is playing in the background. It's very separated and I can trace the synth noise if I concentrated on it quite easily. There's an electric guitar playing during some parts of the song but I feel like the energy was quite lacking. I think that the treble of the W4 is pretty tame, but that's what I like. I also think that the energy is lacking probably because of the song itself.
Kugatsu - Kalafina (After Eden)
Okay...no more brostep and prog house...even though they're my favorite genres. This is a song that's vocal driven with some support background sounds from a piano, xylophone?, and other instruments. Regarding the voices, Kalafina is always the judge for my mids. I love female vocals, enough that I bought a pair of ESW9s to listen to female vocals. Their voices sound powerful and deep. There doesn't seem to be anything wrong with their voices in that it doesn't sound weird. There might be a slight digital like sound to their voice but I don't know if that's the earphone or the processing that was done. Otherwise, they sound great. The xylophone in the background comes out really clear and even though it's in the background, if I concentrate, I can hear each individual note playing. Oh god I am horrible at describing music. Although the voices sound good, it doesn't have as much presence as the ESW9, but I can't fault the Westones for that since they come close enough to it. The piano that plays doesn't seem to have a lot of power and weight behind the notes...but I don't expect it to have that in this song...just a mental note.
キセキノハナ - Rimi Natsukawa (歌さがし ~リクエストカバーアルバム~)
This song is one of my favorites to test out vocals. It's one of those songs where I just get goosebumps listening to it, even though I don't know what the words mean. The piano that's playing in this song has a lot of power and weight. The acoustic guitar that's used in the song is also very clear. About 1:50 the song gets a little busy, but it never gets muddied. Her voice is still amazing throughout the song, and her voice has a lot of weight with the W4. I think this song is better on the W4 than it is on the ESW9 because the W4 has more bass. When she sings, the bass adds an extra texture to her voice and makes it stellar. It's less forward than the W4, but it doesn't bother me because I think it is better that way for this song.
Phoenix - Lisztomania (Wolfgang Amadeus Phoenix)
I like this song because it is very easy to separate the instruments, even with iPod earbuds. When I listen to this song through the Westone, what I look for is separation and detail. If I listen to the guitar, it comes out really clean and clear. The bass guitar is the same. It doesn't sound like it's just a strummed together sound. When the synth mixes in with the drums, guitars, and the singer's voice, things usually get a bit messy. With the W4, it wasn't messy at all and I was able to hear each instrument. The bass guitar has presence, and the drums are very clear. The cymbals sound a bit weak, but the snare comes out well. There is no hissing sound when the snare is played. The kick drum also very nice because it's very present, but it never seems to mess with the music as a whole. Normally, the kick drum would make the vocals seem a little in the background but this isn't the case with the W4.
Haruka Nakamura - Harmonie Du Soir (Twilight)
This is one of my favorite downtempo albums. For this song, there's brass, piano, and drums playing. There's kind of a jazz feel to it. The piano has nice weight and decay. The brass that are playing sounds nice as well, but the bass isn't there. I think that it is because the artist did not want to overwhelm the piano. Overall, the brass instruments sound really tight and feels very controlled. I can tell there's a decay to parts of it, compared to just a generic sound. Also, the piano goes beyond the ears, which is great, but for some reason, the brass instruments. Not sure if this is because of the song itself, but I will have to test with another album. This whole album is really relaxing to listen to.
John Coltrane - I Want To Talk About You (Soultrane + Dakar)
I like jazz, but I can't really describe it well. In this song, the sax comes out really clear. The decay is really good with these earphones, and the piano sounds superb. The piano sounds a bit far away and I can't feel it's presence as much, but it's still good. It's probably what I'm just used to, not a deficiency of the album. The cello(?) is really clear and I can hear all the notes that are being played. The sax has a really deep feeling about it. I don't know how to describe it, but I can feel the emotion oozing from it when I listen to this song. I can also make out the scratching snare sound which is nice, since most of the time it comes out as one sound...almost like static. I feel like I can imagine the drummer doing his motions because the W4 is so detailed. This recording feels a bit in the head, but I expected it to be this way. Plus, I like jazz like this.
Big Boi - Daddy Fat Sax (Sir Lucious Left Foot: The Son Of Chico Dusty)
The bass, although not really detailed, hits hard enough for me to enjoy this song. The synth are all clear never mixed up. The voice comes out really clear and allows me to sing along (horribly) because I can actually hear the lyrics. Usually with these kinds of songs, I judge my enjoyment by the motions I make with my body. With the W4, I initially thought that it would not have enough bass for me but I'm still movin' and groovin'. The midbass is tight and doesn't sound flabby, and the sub bass in the song has enough thump to satisfy my tastes.
(Sorry for the poor song choices...I just randomly chose from my iTunes list)
I think I'm just rambling at this point, so I think I will stop for now. To summarize, bass is really good. Sub bass and mid bass is not as strong as other earphones but surprisingly good for a BA. It is good enough for brostep, dubstep, house, hip hop, etc and I don't think anyone will be disappointed unless they REALLY want something strong. In that case, the Dr. Dre Beats are probably a better choice for them. Mids are really good but I agree with other people that it isn't as strong as other options out there. I personally believe that although the mids aren't as great as other headphones/earphones, with the W4 sound signature as a whole, it just works. Highs feel subdued at times, which makes it seem like it's not as energetic, but I personally like it. I have went up and down from Grado to Beyer and I find that the highs are perfect. Plus, I wouldn't be able to listen for such a long period if the highs are always in my face. Soundstage is pretty good for what it is, and I believe that it does allow for some transparency to shine through. It's the only earphone I use and I don't feel the need to upgrade, which is already pretty good for me.
I use the BART and MUNI in San Francisco everyday. The isolation is good, but it is highly tip dependent. At the moment, I use the Earportz which provides pretty good isolation, but it's not as good as something like the HD280's head hugging clamp of comfort. There doesn't seem to be any microphonics and my steps don't seem to transfer up to my ears, so it makes listening to music on the go much more enjoyable than my DBA02s.
/rant