What is RA file? 

RA is the file extension for the RealMedia streaming audio container format developed by RealNetworks.

RealAudio
File extension: .ra
MIME type: audio/vnd.rn-realaudio, audio/x-pn-realaudio, audio/x-realaudio, audio/x-pm-realaudio-plugin, video/x-pn-realvideo
Developed by: RealNetworks
Type of format: audio file format

WAV File Extension

Waveform
File extension: .wav
MIME type: audio/wav
audio/wave
audio/x-wav
Type code: WAVE
Uniform Type Identifier: com.microsoft.waveform-​audio
Developed by: Microsoft & IBM
Type of format: audio file
Extended from: RIFF

Convert RA to WAV with Mini-stream Ripper