heres what the rpg maker site says about sound:
You have five different file formats at your disposal: MID (in BGM and MFX only), OGG, WMA, MP3, and WAV.
Background music- usually in MID format.
Background sounds- usually in OGG format.
Music effects- usually in MID format.
Sound effects- usually in OGG format.
Here are the special features of each file format:
MID- MIDI files played via the DirectMusic Synthesizer. If a BGM MIDI file contains the control change value 111, that value is recognized as where the song will start repeating after it reaches the end.
OGG- Files containing compressed Ogg Vorbis data, known for its sound quality and compression rate. However, since RPG MAKER XP doesn't support OGG streaming, the entire file must be loaded before it can be played, making it unsuitable for longer pieces.
WMA-Compressed Windows Media Player sound files, played via DirectShow. Unlike the
OGG format, streaming (loading data while playing it in real time) is supported, so it's good for longer-playing songs.
MP3- An extremely popular compressed sound format, played via DirectShow. It has the same special traits as the WMA format.
WAV- The standard Windows sound format. RPG MAKER XP can process both standard uncompressed WAVs and Microsoft ADPCM files.