Spatial audio is another term for surround sound. Traditionally, surround sound has referred to audio systems with multiple speakers placed around a central area in order to deliver sound from several angles at once. For example, a Dolby surround sound system can have eight or more speakers carefully placed to deliver an immersive listening experience for compatible audiovisual content.
With spatial audio, different sounds can appear to come from different directions and heights in relationship to the listener. This can help place the listener right in the action when watching a movie or show, and it can even enhance the listening experience when listening to music. Regular stereo music doesn’t necessarily take advantage of spatial audio, but tracks specifically designed for the technology provide a completely different listening experience.
Apple Spatial Audio is a virtualized surround sound format developed by Apple which requires Apple hardware. It’s designed to add height and rear audio effects to compatible audiovisual content, including Apple Music, FaceTime, and other apps that support Dolby Atmos, or just 5.1 or 7.1 channel audio in general.