[w0lverine]

@ w0lverine: I am admittedly a tad OCD when it comes to hissing. The rational part of me knows full well that once the music starts playing, the hiss is essentially entirely covered up, but somehow I have convinced myself that it is still there in the background, detrimentally affecting my enjoyment of the music... I know it's silly, but this is the sort of pedantry that sets us audiophiles apart from sane and practical people, right?

Exactly ! I'm really in no position to judge you on this one

YMMV, but going from the UM2 to the W4, I would say expect: a bigger sound stage; less "warmth"; less bass; more treble and "sparkle" up top, better instrumental separation, and possibly worse isolation.
 
 

If anything, I would love sharper and deeper bass on my next IEMs, although I wouldn't mind bigger sound stage. Thank you for your feedback, I'll browse my choices when the time of change comes !

I'll probably buy the volume controller today, I'll keep you guys informed.

Thanks, it's a always a pleasure to learn with you guys !

 

[Jeremypsp]

Quote:

Ahh yes, I agree with you on the SE535 point. The SE535 would be the second most sensitive IEM I have tried/owned, but the UM2 is still louder/more efficient by some margin.
 
As for the W4 being warmer and darker, may I ask what tips you are using on the W4? Because when comparing the W4 and UM2 using the same tips, I always sense less treble from the UM2. One of the more substantial UM2 threads from recent times is this one: http://www.head-fi.org/t/575541/westone-um2-the-forgotten-classic . Quoting Spyro from the thread (I hope you don't mind, Spyro!):
 
There seemed to be pre-conceived notion that when W3 came out…then the UM3X six months later, that UM2 all of the sudden became an expensive lower tear IEM.  But if people are not considering UM2 (for whatever reason), in the $220 price range they are really missing out on one hell of an IEM.  It is one of few dual drivers I have heard that isn’t lean sounding.  It has a richness and fullness that is normally found in triple drivers and above.  The one caveat I will say is you should be willing to use the treble booster EQ.  Without it some may find the treble too rolled off.  I am using an Ipod Classic with  treble booster setting + Ibasso T3.  The sound is fantastic as UM2 is one of the more friendly EQ’able IEM’s out there. 
 
I cannot imagine ever using the iPod Classic's treble booster with the W4 because I find them very sparkly as is. Personally, I can only get my W4 to sound "warm" if I use the long Comply P series tips. But I have also read lots of posts of users saying that the W4's treble is quite rolled off/smooth/unoffensive. I suspect the discrepancy between our opinions is caused by tip selection?
 
Back to the topic of loudness and efficiency, I find that the W4 is much less sensitive than both the SE535 and the UM2, and therefore much more amp-friendly. I get quite good results running my W4 from the iBasso t5 mini amp.

True, the W4 are less sensitive. Though the W4 has a slightly too much bass for me and I would prefer a little more spark to the treble. 

 

[csommers]

The UM2's are definitely sensitive (it's not just your ears). I use them mainly out of my older 4Gen iPod and for most tracks I have to put the volume @ ~ 3-5% (hardly any black bar showing on the slider). As for hissing: yep, got that too. They are basically un-useable direct from my MBP, the hiss is REALLY apparent. 
 
I really do enjoy the sound signature, but yea...they're super SUPER picky.

 

[Jeremypsp]

Quote:

The UM2's are definitely sensitive (it's not just your ears). I use them mainly out of my older 4Gen iPod and for most tracks I have to put the volume @ ~ 3-5% (hardly any black bar showing on the slider). As for hissing: yep, got that too. They are basically un-useable direct from my MBP, the hiss is REALLY apparent. 
 
I really do enjoy the sound signature, but yea...they're super SUPER picky.

Weird how you guys can have them so soft and can still be so loud. I used it on my Walkman and the least I need was maybe about 16-17/30. Don't know if it's just my ears spoiling but for other IEMs, that seems to be normal...