the screen never dim off . you have three scale of back-light to choose from but no off -lrb- rather annoy if you like to sleep in the dark and have a watch to check at time -rrb- . also , the sound be 5-10 second recording that be loop over and over , and you start to notice it as you clear you mind to go to sleep . it do its job , but do not expect total relaxation , nor a natural like feel .