Usually Sony products will be slightly pricey than other brand which is having the same level sound quality. Of course Sony products do have a good build up quality.
xba-1 is quite entry level as compare to RE400.
Re400 is typical Hifiman sound signature. Natural sounding like a speaker, focus more on mid as the sound expansion on treble and bass is not very much. Not very punchy but comfortable for long time listening. If you prefer more pop sounding IEM, probably can consider sonic.

Or I should say RE400 sounds more flexible, GR07 sounds more direct. RE400 is nice for pop ballad as well.

oh, then which one is good in producing sound?

They're 2 very different headphones, they don't compare to each other directly.
But since you don't like bass, you won't like either anyways.

Do you prefer open or closed heapdhones in the first place? You've gotta make that choice first.

The Xonar DX is a poor soundcard to run any headphones from due to its insane over 100ohm output impedance.

If you want something more neutral and still have a little bit of warmth, check out the AKG K612. Alternatively, if you can find a cheap second hand Q701, get it. Replace the earpads with the K712 pads for deeper bass and get a baby cloth handle to put over the headband if you can't stand the Q701 'pads of doom'.

The X1 isolates nothing at all, even worse than the CAL! when it comes to keeping ambient noise out.

Using the M50x, in comparison to the old M50, it's a slight bit less bright and a little more refined in the mids. The bass now has a little more impact and control but quantity/body remains about the same.
If the M50 sounded muffled to you due to its V-shaped signature, the M50x wouldn't sound a whole lot better.

Maybe take a look at the SoundMagic HP100. They're one of the best when it comes to passive noise cancelation, but again by no means it has an airy soundstage. However it is a fairly neutral (for its price) closed headphone, there's still the inherent distortion and recessed mids, but that's the weakness in closed headphones.

Other alternatives like the Beyerdynamic Custom One Pro, DT770 AE, and DT770 Pro, they do have really good imaging. But once again, the mids are definitely recessed and they aren't much more forward than the M50x.

You can't have both, unless you're willing to pony up for the Alpha Dogs, TH600 or TH900. They are a special breed.

Did some poking around on the web. Apart from Bose, which ones are a good alternative?

http://www.cnet.com/topics/headphones/best...oise-canceling/

IM70 soundstage isn't that wide. But extremely well on the mids (vocals and a lot of air instruments like flute etc etc) and really good on the lows as well. But highs are... quite soft. The mids and the lows over power the highs.

What music do you listen to and what's your budget?

The cause of sibilance is usually due to poor sources rather than earphones 

Hadn't had much experience with IEM/earbuds. the only experience i had was Phonak 232 (very good balanced, my favorite so far), and FAD piano VIII ( piece of crap, i wonder how they can sell it at the initial USD 1,000 price, no offence to FAD lovers out there). But the pistons for me is just for general use to block out office squabbling and gossiping LOL. If its better than I-buds or beats earphones why not?