[Spyro]

As much as someone may want to doubt or have disbelief or be frustrated that they just bought the W4R, or that Westone has NOT "publicly" talked about sound changes......the W40 DOES sound undeniably different than W4R.  Almost enough, to me, that I would almost consider it would have been worth calling it another IEM model # (well, I guess they did but didn't acknowledge sound changes).
 
Earphone Solutions, Westone rep Cody and 4-5 Head-Fiers that have picked up W40 all acknowledge definitive differences between W4R and W40.
 
Cutting to the chase there is definitely more bass and I find the presentation a little more closer and intimate.  That's it.  Some of the others have reported better clarity and wider soundstage but my memory has those traits equally good with the former W4R and without having side by side I just can't say.  The added bass could be something as simple as adding 3-6dB to one of the bass drivers as a "boost" and, of course, the housing and cable are completely different which could also add to SQ changes.
 
IEM's that have amazing detail speed and transparency tend to be cold, analytical and lean on bass.  That's the trade off.  The other side of the spectrum has big full sounding and warm IEM's that lack speed precision and detail.
 
W40 really nails it right in the middle.  Much moreso than UM3X/Pro30, W3, SE535.  The overall signature is warm and lush and very non-fatiguing.  The clarity and treble is among best in class at that pricepoint while the bass is more than adequate except for extreme bassheads.  Nothing sounds out of place, no spikes, no boosts, etc.  Imagine a very well balanced and neutral IEM with a large soundstage....now give it a very subtle and mild subwoofer effect to fill the sound out and you have W40.  Unless you are a treble head and Ety fanatic, the W40 should please virtually everyone.  It basically fixed the only real issue I had with W4R which was a bass effect that was a little on the lean side.  With W4R the bass was okay and would not distort but it seemed I was squeezing every ounce of bass out of the earpiece.  With W40, the bass comes across much more effortlessly.
 
Until I can plunk down $1000 for an IE800 or SE846 (the two I would have in mind) I am set with W40 and done!  It's awesome and I have no faults to point out with it...it doesn't do anything wrong and doesn't really lack anything.
I'm also done with customs as the risk is too high that they don't fit right.  There are no guarantees and high end universals are just getting too close in SQ to customs.

 

[Tramtox]

I see you are very positive about the W40. I personally have the UM Pro 30, and I do like them, but I was wondering how much an improvement the W40's would be. I mainly listen to EMD, Rock and Ambient but not limited to these. The Pro 30 has grown on me, especially with the highs eq'd a little.
 
Also, I heard some concerns about worse build quality in the new W series? Is that true?
 
The Pro is £300 here in the UK and I can return them still. The W40's are £400. I know value is entirely subjective, but I would like to hear your opinion.

 

[Spyro]

They are both great IEM's.  Everything I am saying aren't necessarily faults as much as observations that could affect preference.
 
Pro30:  Like the UM3X, there is a front and center emphasis on drums that can fatigue if you listen loud and it inadvertently puts the treble a little distant.  It's a bit dominant.  Mids very good but a little more forward than I like.  Treble is rolled off but EQ certainly helps.  If it wasn't for the strong punchy bass this IEM would actually be rather bland sounding.
 
W40:  Like I mentioned before they brought the presentation and soundstage in closer and more intimate which is also a trait of Pro30 but the treble is much more extended and the whole presentation more airy and transparent.  You can really get inside the music.   It makes music generally more beautiful.  I am nuts over the midrange.  Best I have ever heard.  Vocals and acoustic are sensational.  Very present but not really forward.  The bass is a good 15% more present than W4R and a bit thicker.  Just a notch down from Pro30.  Very nicely textured and layered.  Goes DEEP without bloat or sloppiness.  Build quality appears to be fine.
 
So, to me, the more open/airy sound with the naturally extended treble of W40 make it the no-brainer better IEM over Pro30.   Can't really say Pro 30 does anything better than W40.  Pro 30 has a little more bass but not sure I would call that a better thing.  The Pro30 seemed more co-heasive sounding than W4R but W40 is sounding pretty cohesive to me.  Granted I don't have golden ears.

 

[OPAgusta]

Hi spyro, how would you compare it to jvc fx-700 especially in term of low and timbre? I belive the bass in fx-700 has more decay since it is dynamic IEM as compared to W40 which has faster and tighter bass since it is amature. Would you say they are in totally different class altogether? I know fx-700 can be a little thin in mid due to the v-shape nature of the sound. I listen to trance, progressive, house, electro house, techno and electronica. Example: Armin, Tiesto, deadmau5, Old Daft Punk (not cheesy mainstream Daft Punk nowadays).

I am now using Klipsch S4 but the bass is too much and makes my ear hot. Now I am considering to update my gear. My mp3 player is 60 gb classic iPod which I believe has good sound quality (at least compared to ipod touch).