

If you are targeting Mac and PC platforms only (including both standalones and webplayers) then importing an Ogg Vorbis file will not degrade the quality. For the best sound quality, supply the audio in an uncompressed format such as WAV or AIFF (containing PCM data) and let Unity do the encoding. Depending on the target, Unity will encode the audio to either Ogg Vorbis(Mac/PC/Consoles) or MP3 (Mobile platforms). Compressed: The audio data will be small but will need to be decompressed at runtime, which entails a processing overhead.
