What are the legalities on hosting edited copyrighted music on your website?

I own a legal copy of the full albums and the entire discography. I am editing the 320kbps mp3 files down to 15 second clips at 128kbps. I intend to add these brief clips of each song to a discography section of my website, as I think it's a good feature. I am unsure how legal this is though? I do not want to ruffle any feathers with anyone, I'm only trying to share my love of a band by allowing others to hear samples of their work (in most cases edited to capture the chorus, or main riff - the recognisable bits!)