WAV - RIFF WAVE file: This audio file format is widely used in all Windows versions and in other operating systems. Spark can use any type of RIFF WAVE file, if the corresponding audio codec is installed on the system.

ITS - Imuplse tracker sample: This format is supported mainly for compatibility with the previous versions. Impulse Tracker is a DOS-based module editor by Jeffrey Lim. It has a special sample format, whcih allows setting loop positions. Spark can use all non-compressed ITS samples. (Note: Streaming of ITS samples is not supported.)

OGG - OGG Vorbis file: The xiph.org foundation's free lossy audio format. It's similar to mp3, but more advanced. 

XM - Fast Tracker II module: It is a music module format, used by many trackers. Spark's internal player can play all XM modules. All effects are 100% supported. XM modules can be used only as streaming samples.