Author: musetips.com
https://www.musetips.com/
License: Freeware
Requires: Win7/Vista/XP

This is an extremely simple and handy Windows software for editing mp3 files.

Editing Commands:
Delete Selected - Deletes selected part from the mp3 document.
Delete Unselected - Deletes unselected part from the mp3 document.
Change Volume - Changes audio volume by specifying a percentage value.
Maximize Volume - Increases volume as high as possible without distortion.
Fade In - Gradually increases the volume throughout the selection.
Fade Out - Gradually decreases the volume throughout the selection.
Convert to Stereo - Duplicates mono track to make a stereo track.
Convert to Mono - Mixes all channels to make a mono track.

https://www.ryanvm.net/forum/viewtopic.php?t=9231