[daviddoock]

i wanted to buy a headphone with great sound stage for around $200 to $400
maybe i can stretch my budget if its reasonable
 
what i have now is ath-m50 which doesn't have a great soundstage. it sometimes a bit congested for some songs.
what sound signature that i am looking is having a good bass response (not thumpy like momentum on ear)
and has more forward mid range than ath m50... and a tiny bit lower highs( not as sparkly as m50) although i like some sparkle.
 
i only have fiio e07k Andes for the amplifier (i know its a cheap and probably not very good amp ,but hey....).
but maybe i would buy some dedicated desktop amplifier next time.
 
peace and happy listening

 

[GREQ]

Sennheiser HD558/598

 

[TwelveTrains]

I think when it comes to soundstage the AKG K701, AKG K702, AKG Q701, and AKG K712 will always be king IMO.
 
 
The K701/K702 would have the absolute best soundstage of the series, but it is a bit lighter on the bass. I still love this headphone though, and the bass isn't too light for my ears.
 
I haven't head the other two, but supposedly the Q701 has a touch more bass without sacrificing too much in the soundstage department.
 
And the K712 even more so, but this one is slightly outside your price range. The K712 also doesn't have the dreaded AKG headband bumps, but these bumps have personally never bothered me. Albeit, I didn't wear it for that long.
 
 
 
As for your amp... I don't know if it can power these headphones or not. Hopefully somebody else can chime in about that. If I had to venture a guess I would say not adequately.  
 
 
Being that you might like some more bass, you could also look at the Beyerdynamic DT770's in 80 Ohms. These have very powerful bass, and a very good soundstage. They are also slightly easier to drive. However, the highs are bright! They are never sibilant to my ears though.