vertix

AKG K550/553 or Audeze Sine Closed

1. Get 80 ohm then you should be fine
2. You should be fine either way if you get 80 oh. 
3. There shouldn't be. If there is it shouldn't be noticeable
Don't get the m50x

The key is that the DIY panel won the comparison because a thick towel is significantly higher density and thus better isolating than the foam. The effects of true sound absorption are miniscule at this scale (in fact, it's a physical impossibility). Hanging heavy blankets helps more due to the mass loading and additional solid barrier they represent than because they innately disperse energy.
 
The panels will deaden reverb within your room, but that's not the effect you're looking for. As for why the towels work, they still reflect less sound, less coherently than the solid walls. There's a reason professional studio panels are made of foam despite them being the "worst" material in the video's tests; the video's methods do not test for absorption at all.
 
 

Thin room treatment panels are for dispersing reflected sound internally; they won't do much to isolate you from external noise sources. It takes a massive amount of material to truly absorb sound energy. Generally to keep sound in free air from moving in or out of an area, you want reflective isolation (dense, solid walls). Foam and soft panels are used either to treat a room for recording (reduce the unwanted reflections from the walls) or in large anecholic chambers which have enough space for foam to properly absorb sound (you need several feet of foam to attenuate effectively at low frequencies).
 
The only practical way to decouple sound I can think of for an apartment is to use rubber liners to seal any open air space (beneath doors and the like) giving air free passage between the spaces. Mass loading or mechanically isolating walls and windows so they resonate less would be ideal, but it's not something I imagine you could reasonably do in an apartment.

As of right now, Slime Rancher can be had for free from the Epic Games Store?: https://www.epicgames.com/store/en/product/slime-rancher/home

Sound cards in general are pretty bad. It's all software and crap. The DAC's and Amp's in there are almost no better than today's onboard.

Sound cards in general are pretty bad. It's all software and crap. The DAC's and Amp's in there are almost no better than today's onboard.

this is heresy

I remember when I knew nothing about audio....
 
Go try plugging 103 dB/V headphones into the RCA outs of a DAC. Let me know how that goes for you.

I would get the DAC X6 again in a heart beat.. I was looking at all those when I made my purchase and the versatility of the X6 got me,  I could run this off my PS4, XBOX, PC, TV, LAPTOP, CABLE BOX anything with an audio output I could push it through this unit and use headphones or output to my stereo speakers in my living room with ease via the RCA outputs on the back.   After reading countless reviews online etc the FiiO units from what I remember were really bass heavy and the amp is sub par at least in the K10 I have no info on the K3.   The M3 lacks inputs and the build quality is not as nice imo.
 
 
 
The Amp is quite powerful for this price range my HD6XX at 300ohm are about the limit for it but anything less than that are powered with ease.   
 
I have owned it for over 2 years and have not have a single issue with it.  
 
Also was reading earlier you were looking at just DAC's which would be fine if your running it into a set of speakers or amplifier but you You can't use just a DAC with headphones unless it has a headphone amp built in most only have rca in / out.
 
+ the x6 is the cheapest on your list,  what could go wrong?

I wouldn't recommend as you might get some EMI or noise, but you can just use optical and feed it power through the power supply.

I wouldn't recommend as you might get some EMI or noise, but you can just use optical and feed it power through the power supply.

Don't listen to Zeos, he's deaf, and everyone who actually knows about audio agrees.

Don't even think of getting the 990, It's treble earrape. Get the 880 Instead if you want a more fun sound and get the 6XX if you want a nice laidback listening experience. Oh, and don't even bother with an amp, they do benefit from one but can get loud enough and sound great with or without one.

P.S don't listen to them about that "veil" stuff, It's just a big meme.

Don't listen to Zeos, he's deaf, and everyone who actually knows about audio agrees.

Don't even think of getting the 990, It's treble earrape. Get the 880 Instead if you want a more fun sound and get the 6XX if you want a nice laidback listening experience. Oh, and don't even bother with an amp, they do benefit from one but can get loud enough and sound great with or without one.

P.S don't listen to them about that "veil" stuff, It's just a big meme.

Please don't get any of those.
If you want cheap, really good sound that you can take out with you, then the Koss KSC75's would be a great choice. 
There's also the Creative Aurvana Live which are much better than every headphone listed above sound-wise. (M1060's included)  Now-now, if you want IEM's there are a bunch of good one's to pick from. Here are some that I know of
BGVP DMG, Tin Audio T2 and Vsonic GR07. Here's a ranking list you might like and find useful for picking out IEM's.

If you'd like, I could recommend some more headphones if you could give me your exact budget.

2.5mm outputs are usually used for IEM's, not headphones. If you do want to though, you'd have to mod your AD900X's, make the cable detachable and get a new one that does balanced 2.5mm since you can't just convert 3 pole 3.5mm to 4 pole 2.5mm. Even so, I doubt they'd benefit much from the extra power.
 

Yincrow X6 and RW9. Both under $20 and are excellent for their price.
If you want more, just go through this list and select from your sound preferences https://crinacle.com/ranking-list/
just note that this list is for in ear's

Definitely not.
I don't have much experience with IEMs but, I know that that list is pretty good for figuring out which IEM you want to be buying.
Check out Tin Audio T2 if you want something cheap but good, they're a little dark but are pretty solid.