An SW file is a "signed word" audio file. The "signed" part of the name means the value for each sample can be positive or negative. Because it is 16-bit, each sample may contin 16 bits (or two bytes) of data.

SW files are raw files, meaning they are uncompressed. Therefore, and SW file will require significantly more disk space than a comparable compressed audio file, such as an .MP3 o4 .M4A file.