I'm looking for a 'slow, mellow, chill out' Blues album?

Got a few albums and they seem to be of a mish mash of different types of blues. I'm looking for an 'in the alley' type of slow chill out blues CD. Got a few rockin boogie woogie albums and want something slow and mellow to listen to when i'm in the mood. Anyone got any suggestions or know what this type of blues is called then i can search myself ?