Sounds can either be simple (as in a normal mono or stereo sound) or positioned in 3D space. A positioned sound is attached to an object in the 3D world via script, and depending on the position and orientation of the camera, will sound as if it's coming from the object.
Simple sound - This is the default type of sound. It can be used anywhere except as a sound attached to an object, for which you need a positioned sound.
Positioned sound - A sound that is played in 3D space (i.e. attached to a 3D objects). The result is such that if the object to which the sound is attached is to the left of the camera, the sound will come from the left speaker, etc. For this reason, positioned sound data must be mono.
Polyphony - This is the number of simultaneous copies of this sound that can be playing at once.
Looped - Check this box and the sound will loop.
Intro - When a sound is first played, the intro sound will be played once.
Outro - When a sound is stopped, the outro sound will be played once.