Sound-banks: Every sound-event can contain one or more sound-banks (q.v. About sound-events and what they're capable of...). A sound-bank is basically a collection of similar sound-effects, like for example different dogs (barking), tolling bells or thunderclaps. Each sound-bank may contain several files (sound-effects). This creates an ever changing scenario of barking, tolling bells, or thunderclaps that will be played, despite the same sound-event being active. This creates a realistic impression of the scene and prevents tedium.
A sound-banks other options determine the general performance of the sound effect, e.g. whether it is repeated infinitely or only played after a certain time span and so on.