The Next Step ("upgrade") After Fidelio X2's, HD600, and ATH-AD2000 (Goodbye Wallet)?

[rnros]

looking for something "enveloping"
 
Sounds like you might want to consider an amplifier upgrade at this point. If you go with one of the Schiit amp options, dollar for dollar, I think it will make a bigger difference than new HPs.
A tube or hybrid amp also allows you to roll tubes for different sonic qualities, can make a big difference. Good tubes are available without spending a lot of money.
 
Of course that won't help your portable setup, but for your desktop listening...

 

[Feilong4]

  looking for something "enveloping"
 
Sounds like you might want to consider an amplifier upgrade at this point. If you go with one of the Schiit amp options, dollar for dollar, I think it will make a bigger difference than new HPs.
A tube or hybrid amp also allows you to roll tubes for different sonic qualities, can make a big difference. Good tubes are available without spending a lot of money.
 
Of course that won't help your portable setup, but for your desktop listening...

About 4 months later, I saved up enough for the Bottlehead Crack w/Speedball. Of course, that's because many other headphones and IEMs came in the way before the Crack but the tube amp came eventually nonetheless. 
 
The Crack w/Speedball and the HD600 sound very good together. Apparently the best combination. I'm really gradually appreciating the Bottlehead everyday. Definitely sounds "enveloping" as I wanted! Maybe even a little more then I would be in audio nirvana.
 
HD800/T1 HERE I COME!!

 

[rutter]

Get the Sonarworks VST Plugin. You'll love yourself for doing it. It has a free trial.

Does the post-trial version of True-Fi have unlimited manual eq?

 

[BunnyNamedCraig]

About 4 months later, I saved up enough for the Bottlehead Crack w/Speedball. Of course, that's because many other headphones and IEMs came in the way before the Crack but the tube amp came eventually nonetheless.

The Crack w/Speedball and the HD600 sound very good together. Apparently the best combination. I'm really gradually appreciating the Bottlehead everyday. Definitely sounds "enveloping" as I wanted! Maybe even a little more then I would be in audio nirvana.

HD800/T1 HERE I COME!!

I think the HD800 was suppose to marry a tube amp. I think the combo is so excellent together... I have always wanted to hear a T1 off of a tube amp but haven't had a chance yet. I love the T1 version 2 more then the original though. Given your tastes "like when the bass drops" the T1v2 has a better chance of satisfying that. the original is dang near bass anemic.

HD800 will get better bass with your tube amp. If you like the amount with the HD600 with that combo then the HD800 should be enough as well. All my opinion of course!