I write in fear that this topic has been covered on the forum before.
the 2 main contributors to poor sound quality from internet radio are
1-- the standard sound card in your pc
2 -- internet stations that broadcast a standard mp3 stream usually 32 to 128 kbps bitrate
To get much better results
1 --upgrade your sound card to an audiophile sounding card such as M.audio Audiophile 2496
2 go online to an internet station that broadcasts using aacPlus encoding such as
click on the aacPlus plugin for the player type in your pc ( real player , media player or winamp)
and listen to the amazing improvement !!!!!!!!
either upgrade can be done alone of course do both and double the pleasure