Never mind that Bathtime Magic, the sixth in Discovery Music's series of tapes for children, is a little too slickly packaged. Never mind that making music to wash by is kind of like putting the bathwater before the baby. Never mind that if you actually kept your tiny bather in the bathtub through all of Bathtime's 15 songs, he or she would emerge a human raisin, or that my tot begged me to put the tape player in the water with her, after which she might not have emerged at all. Never mind any of this, because Bathtime Magic is a great collection.
Singer Joanie Bartels (she does all the Magic Series tapes) has a wonderful voice, and material equal to it. Some of these songs began life as Top 40 hits: Bobby Darrin's ''Splish Splash'' (''I was takin' a bath''), the Beatles tunes ''Yellow Submarine'' and ''Octopus's Garden.'' Others are classic children's songs: Raffi's ''Bathtime,'' Jeffery Moss' ''Rubber Duckie'' (made famous by the inimitable Ernie of Sesame Street).
Nothing sounds like elevator music (a real danger with any Beatles tune). The arrangements are frisky, and so is Bartels, especially on the old kiddie tunes ''Three Little Fishes'' and ''The Little White Duck.'' Refreshingly unhip, untouched by mournful political or ecological relevance, this is entertainment. A