The GPK file contains a summary of data taken from sound waves. Since many different programs may use GPK files for different purposes, you may need to try a few of the apps to open your specific GPK file. It contains analysis tools for detecting and correcting errors hidden within the the audio material's frequency spectrum. Technical Data for GPK File Extension. Contains a summary of sound wave data for an audio file opened with WaveLab; enables faster reloading of audio files in the program; created automatically when an audio file is opened in WaveLab. Geos Compressed Omnigo File Archive, Omnigo Program Package, and WaveLab Peak File are some of the popular programs that use the GPK file extension,.