Hey guys so I am trying to work more on my knowledge of how bass relate to different things. I know for bottom hardness they like to spawn on harder bottoms, but when else do they prefer hard over soft, or vice versa? Thanks guys!

http://www.bassresource.com/fishing/iaconelli_bass.html

http://www.bassresource.com/fish_biology/location.html

Read these if you haven't already... Good stuff!

Outside of the spawn when the bass seek out gravel hard bottoms, I concentrate on the edges where two bottom compositions meet. Sometimes this works like a weed edge or shade line etc. Beyond that I think it depends on where the bait is. If the primary forage is seeking one type of bottom for some reason I'd expect the bass to follow the bait, not necessarily attracted by the bottom composition alone. 

Thanks guys! I appreciate it!