AU is an audio format standard in early web pages NEXT systems. It is also called u-law or Sparc-audio format. Typically, AU files can store audio data and annotation blocks. Initially, it was a headerless audio format, but newer versions have a header, thanks to the six unsigned 32.bit words.
WAV, sometimes called WAV, is an audio container format developed by IBM and Microsoft and comes with a .wav filename extension. Unlike popular formats like MP3 and MP4, WAV isn’t a lossy format, so it’s bigger and less popular. WAV files can be opened on various OS platforms via software like Windows Media Player, MPlayer, VLC Media Player, and more.