While I haven't heard the W4R in 3 months I am very familiar with it having owned it for about 6 months total.
I am 100% certain the W40 has more bass than the W4R. I would put $50 down on a bet. It is very possible all the same drivers but perhaps one of the bass drivers was tuned to add 3-6 dB? The soundstage, the slight "veil", the terrific treble extension and transparency is all still there the same as W4R to my ears but I swear there is a heavier bass emphasis. That's the main thing and maybe the housing change does something else but I cant tell.
As I waited for the W40 to arrive I have been listening to my JH5's which are anything but bass light. I remember previous when I went to W4R there was an adjustment with "lesser but better" bass response. With W40 there is ZERO adjustment period except perhaps JH5 is "brighter" sounding where W40 is warm and slightly dark.
If you can find them in the $400 range I am very convinced they may be the best IEM out there at that price. An "all-arounder" in every sense. It might be personal preference but easily the best midrange of anything I have stuck in my ears. Just like W4R, not overly forward but VERY present....perhaps it is the amazing detail and transparency. Swear to God I would take these over the JH13's I owned. More musical....more lush...with still tons of detail.. Anyone that would be bored with W40 might have hearing problems. Maybe best option of "balanced and fun" of any universal IEM out there. And no....I haven't heard them all.
Edited by Spyro - 3/2/14 at 4:10pm