There is dream pop and there is whatever Liz Harris, aka Grouper, has evolved the genre into. Hers is the dreamiest of dream pop, a sparse aesthetic that comes in and out of the haze, making groups like Low or Mazzy Star seem far too fast or stirring in contrast. With her newest album, “Ruins,” Harris channels all the serenity of her previous work, combined with the stark melody work found in the best of Harold Budd. As such, the work is austere and beautiful, if but more than a little melancholic, rivaling her Kranky Records contemporary (and Louisville native) Tara Jane O’Neil’s most recent work in terms of elegance and gracefulness. This is a delicate and delightful affair — contemplative but not overbearing, perfect for lulling you to sleep, or for relaxing somewhere, snuggled up with a good book.