An AWB File (Atom Wave Bank file) is a file which contains the waveform data referenced by a CueSheet, encoded by the tool.
The ACB file is referenced for the parameters required for playback.
An AWB file is generated when building the ACB file if the CueSheet contains one or more referenced materials having their Streaming Type set to "Stream."
It is not generated if the Streaming Type of all the referenced materials in the CueSheet is set to "Memory."
CRI Atom Craft does not provide a way to generate only the AWB file, but you can generate an independent AWB file using the CRI Atom Encoder tool.
Note that ADX provides a feature to directly play back the content of an AWB file (for the rare cases when basic playback of encoded data is enough).