Increase Media Player Classic volume to more than 100%
Sometimes the audio volume of media files is so low that it is barely audible. When faced with such files, you may want to boost the volume above the maximum level. Media players like VLC and mpv allow you to do this very easily. Boosting or normalizing audio is a little less convenient in Media Player Classic, but it can be done.
warning: Increasing audio volume above 100% percent causes audio distortion; it may harm your audio equipment; extremely loud sounds could even cause hearing damage. Prolonged exposure to moderately loud sounds also causes hearing damage. Use this option only for files whose volume is very low.
View menu ☰ ➾ Options ➾ Internal Filters ➾ Audio Switcher.
First, enable the built-in audio switcher. This would make the boost volume and normalize volume options active. Choose either normalize or boost to increase the volume. Normalize sets the peak volume in your track to the desired percentage and adjusts the rest of the track relative to the peak. The boost option amplifies the entire track by the desired value.