Sound Card for me?

[g4kioN1]

Hi, i just purchased the Logitech z623's today and i think they are some amazing speakers, when i blast the base and push the volume my music is very clear. as you can tell if i think sub 150 dollar speakers are amazing you can tell that im new to audio. please suggest what headphones and soundcard combo i can use to get similar performance except inside some cans.

i really want the asus xonar stx with hd555 but i feel that it is overkill. i listen to a lot of rap (lupe, nas, tupac, eminem), techno, and all genres of rock. im pretty set on any sennheiser headphones but the xonar's internal amp is what catches my attention.

on the back of my sub woofer i have a 3.5mm jack and red/white rca.

am i able to use a cable(rca to 3.5mm) to connect from the rca(soundcard) to 3.5mm(sub woofer) and have the amplified head phone jack or line out for my hd555s

ps i have always used my onboard audio how much of a music improvement am i going to see when using this setup?

this setup is for music only, gaming audio doesnt move me and my 5870's hdmi leads to my tv and im satisfied with the audio of my tv.

thanks ahead and please let me know what would be comparible setup to these speakers

http://www.newegg.com/Product/Product.aspx?Item=N82E16829132010&cm_re=xonar-_-29-132-010-_-Product
http://www.amazon.com/Logitech-THX-Certified-Speaker-System-Z623/dp/B003VAHYTG/ref=sr_1_1?ie=UTF8&qid=1302497480&sr=8-1

 

[g4kioN1]

anyone?

 

[g4kioN1]

i use my computer for everything, but i have a dedicated headset for gaming, razer megalodon. now i like this headset for gaming and thats about it. im gradually becoming more picky about music. but music is my main concern. ty

 

[MEgamer]

find a midpriced one, and avoid creative, -you should have a fair improvement.

 

[MEgamer]

wtf... i did my post go all the way here????

 

[MEgamer]

and asus has the GX engine, works as okay.

 

[g4kioN1]

thanks for the response guys so pretty much any soundcard will give pretty good improvement?
i'm pretty big on numbers and accuracy so is there anyway that yall could list sound cards and the percentage it may improve my normal sound?

maybe price for performance?