Originally Posted by: Slipin Lizard... When the backing bass line is in Cmaj, the riff sounds like Cmaj, very upbeat, happy, whatever you want to call it. Then, when only the bass line changes to Amin, it sounds like the riff changes too. You'd swear I'd changed the scale/notes, it just sounds so immediately "minor", but nope, the riff stays exactly the same, and as soon as the bass goes back to Cmaj, bing! it sounds like the riff is back to Cmaj too...

This along with Chris' post helps clarify. Thanks