SampledSoundList[, , ... , r] is a sound primitive, which represents a sound whose amplitude has levels sampled r times a second.
SampledSoundList[, , ... , r] yields sound on several channels. If the lists are of different lengths, silence is inserted at the ends of shorter lists.
SampledSoundList is generated by ListPlay.
SampledSoundList primitives can appear inside Sound, Graphics and Graphics3D objects.
See The Mathematica Book: Section 2.9.18.