Good God! That is tacky! I think you'd agree too, if the focus would have been on what it should have been instead of that shit, more progress could have been made toward dirt cheap, high quality audio. It is minor and I think I'll just live with it.
When you say loopback, I'm assuming you're speaking of this (just an example):
http://icrontic.com/discussion/90386/en ... dmax-audio
The main source of processing noise in onboard (and laptop) sound is the power rails not the sound chip itself. You need proper filtering on the power rails but that requires fair bit of big and expensive components.
All cheap standalone sound cards suffer exactly the same due to lack of these filters.
Other reason is poor trace routing and shielding but that's because of lack of space, which isn't a problem on standalone cards.
In any case if you want good sound look at some old pro equipment.
I got some of that in my computer :
http://www.tmeeco.eu/BitShit/DS2416.jpg
http://www.tmeeco.eu/BitShit/SW1000XG.jpg
http://www.tmeeco.eu/BitShit/YamahaAX440.jpg
http://www.tmeeco.eu/BitShit/Asound1.jpg
http://www.tmeeco.eu/BitShit/EvenMoreAudio0.jpg

All cheap standalone sound cards suffer exactly the same due to lack of these filters.
Other reason is poor trace routing and shielding but that's because of lack of space, which isn't a problem on standalone cards.
In any case if you want good sound look at some old pro equipment.
I got some of that in my computer :
http://www.tmeeco.eu/BitShit/DS2416.jpg
http://www.tmeeco.eu/BitShit/SW1000XG.jpg
http://www.tmeeco.eu/BitShit/YamahaAX440.jpg
http://www.tmeeco.eu/BitShit/Asound1.jpg
http://www.tmeeco.eu/BitShit/EvenMoreAudio0.jpg

