.PEAK File Extension
What is a PEAK file?
Contains the waveform image of a corresponding Cubase audio file; used for visually displaying the audio data within the Cubase track window; generated automatically when an audio file is recorded or imported into Cubase.
PEAK files are saved by default in the Images folder within the current project folder. If they are deleted, Cubase will recreate the files when the associated audio files are accessed.
NOTE: PEAK files store only the waveform image and do not contain any audio data.