803.1 What Is a Sound Recording?
Sound recordings are “works that result from the fixation of a series of musical, spoken, or other sounds, but not including sounds accompanying a motion picture or other audiovisual work, regardless of the nature of the material objects, such as disks, tapes or other phonorecords, in which they are embodied.” 17 U.S.C. § 101.
A series of musical, spoken, or other sounds requires a temporal succession of sounds rather than a single sound expressed horizontally or simultaneous sounds expressed vertically, such as in a chord.