[fud4ever]

Hi all. Sometime in the near future I will be purchasing audio hardware for use with my PC. I need help deciding what path to take.
 
This purchase is solely for my pair of Ultrasone Pro 900s (which is 40 ohm). I'm trying to decide between an external dac/amp, soundcard/external amp, or soundcard with a built-in amp.
 
I want to achieve extremely clean sound and be able to EQ that sound as cleanly as possible.
 
Now for my noob questions:
1. Does the software/driver that comes with soundcards (ie xonar essence) provide a cleaner EQ than say if I were to use foobar's EQ? If not I will shift my focus towards an external dac.
2. I've read that the Asus xonar essence has an output impedance of ~11 ohms. This is too high for clean sound in low impedance headphones ie my pro 900s, correct?
3. If I'm correct with my assumptions, would I be better off buying a high-end soundcard with no built-in amp, and then connecting that via some cable to a desktop amp with an output impedance of less than 1?
 
What hardware would you recommend in this situation? Budget is not an issue. Thanks for reading.

 

[Roller]

Most DACs offer no sort of sound customization at all, but are indeed the highest quality devices for music listening purposes alone. Although, if you do want to tweak your sound, a soundcard is needed, and something along the lines of a Creative X-Fi Titanium HD would be a good match with the Pro 900s, as it has a slightly warm signature that goes well with the bright nature of the headphones. You can then use the RCAs to send the audio signal to a desktop amp or receiver, and that would make up for a rather good setup.