Do i have to re-educate my ears? I think i've read enough of this forum to trust all of you more than Tyll or head-fi or headfonia. And the consensus seems to be that the setup i have can be an end-game for non-audiophile

Naw you probably just have a preference.  I haven't heard your rig in a while but if you're happy with your set up, who cares what the internet says.  I didn't the x2 was bad when I heard it, but I do like the hd650 better. 

Bottom line if you like the x2 in your setup now stick with that, if you change in the future that's future you's problem

And i like X2's more.

I'm not an audiophile by any sort of definition, i just like listening to music. To me, the biggest difference is bass and probably the soundstage if i understand the term correctly. HD650 feels very.. narrow? It's like the music is very close to ears (obviously not closed-cans close), but at the same time very distant if that makes sense? It's right HERE, but not really. Very strange sound. And it becomes even more apparent when i put on X2's. They sound really wide, i can't even tell where the sound is coming from, because it feels like sound originates somewhere outside the cups. The bass is superior, it had more punch where it needed. Also, X2's draws you into music, while HD650 produced music disappears. It's not engaging.

The only thing i don't understand is why i hear background hiss with X2's while HD650 keeps it clean.

What should i do changstar? I don't want to choose the wrong one, and i took HD650 to leave the mid-fi purgatory. But it seems X2's sound better for me. Thank you.

You didn't choose wrong.

I wouldn't argue against the points you brought up with the HD650. Stage is narrow and depth is flat with HD650s. HD650s in stock form are a bit overdamped or boring (hence the mods I suggested, although I wouldn't suggest mods because the differences are not huge). The X2 are more efficient (the noise you mentioned) and more fun (which equates to a bit too much boom and tizz for me).

Not going to suggest that you spend more money on stuff, but keep in mind that some of the folks here running the HD650s are running them off seriously good DACs / amps. The "scaling" thing is very real; and from what I've noted, a huge reason for many discrepancies. Even then, among the guys who have TOTL type rigs, there are a people who prefer the "lesser" HD650 over the superior HD800, HE1000, or LCD3.

I also agree that the perceived soundstage is not the 650's forte. They've been described elsewhere as having a "three blob effect" and I'd tend to agree with that. If you're listening to large scale orchestral music these are not the headphones you're looking for, but, if more intimate music is your passion - say small scale jazz or folk music - the Senn's could be right up your street. Certainly this is my experience anyway. I also agree that they scale really well too. When I moved from an O2 to the Project Ember MkII it was the closest I've ever came to experienceing the mythical "night & day" upgrade.

Still, they can be tweaked to sound even better in my opinion with the judicious use of a parametric EQ. With the help of Frans (Solderdude) I came up with these settings..

Low-shelf filter of +2dB @ 20Hz with a Q of 1
Mid-range cut of -5dB @ 150Hz with a Q of 0.5
High-shelf boost of 1.5dB @ 5000Hz with a Q of 1

I'm using a Mac mini as transport and JRMC19 as my player. Source is an ODAC.

Using these settings that upper-bass bloom is removed with a little more weight added to the low end. The treble also gains just a little bit more air. I also use crossfeed so if you don't you might want to change these settings slightly. It's also worth remembering that I'm using a tube amp which inevitably colours the sound in it's own way too, depending on the tube used. For the record the best combination of tube & EQ I've come up with thus far has been using a 1951 Sylvania 6SN7GTA 'Chrome Dome'. My HD 650's are the silver driver version and have not been modded in any way.

I know there will be purists who'll recoil in horror at the idea of using EQ and that's fair enough. I don't have a problem with it because I consider using a tube in the first place to be a form of EQ so what the hell. I'd be interested to hear what you guys think.

You didn't choose wrong.

I wouldn't argue against the points you brought up with the HD650. Stage is narrow and depth is flat with HD650s. HD650s in stock form are a bit overdamped or boring (hence the mods I suggested, although I wouldn't suggest mods because the differences are not huge). The X2 are more efficient (the noise you mentioned) and more fun (which equates to a bit too much boom and tizz for me).

Not going to suggest that you spend more money on stuff, but keep in mind that some of the folks here running the HD650s are running them off seriously good DACs / amps. The "scaling" thing is very real; and from what I've noted, a huge reason for many discrepancies. Even then, among the guys who have TOTL type rigs, there are a people who prefer the "lesser" HD650 over the superior HD800, HE1000, or LCD3.

The soundstage and speakers in a room tuning of the 580/600/650 series makes them better for studio music than the HD 800 and HE1000, technically better drivers be damned. There is no artificial width that can put the plucking of the guitar string and distortion in different places or break up the drum kit like an AKG or HD800: different drums panned to different places is seriously messed up on these. I also don't feel the 650 is overdampened for rock and metal; I found long term listening (hours a day, almost every day) of those genres' forwardly miced and mixed drum kits to be slightly grating on the slightly bright 580/600 but perfect on the current slightly dark 650. It lets you disappear into the music without fearing some animal high hat basher is going to ruin your hearing. The veiled black driver one sucked though so thanks for starting this thread which led me to give the current version a try. If you only listen to an occasional rock album you might prefer the HD 600 as it will make the kit sparkle a tiny bit more than on the mix. For orchestral music? Yeah you might something wider and brighter too but I preferred intimate material like the Kronos Quartet on my "metal cans."

The scaling is huge with recordings too. Mixes and masters start to mean a lot more. I've even found the HD 580/600/650 drivers to scale the tone better guitar amps used for tracking in a more lifelike way than lesser midprice headphones. They really make it clear how much better just plugging into a JCM 800 head sounds than a crappy Valvestate is and expose studio tricks like digital reamping.

I have never, ever, heard anyone complain of sibilance on female vocals with the HD 650! A genuine first for me.