Boom 3D - Audio enhancer with 3D surround sound
Kobo Audiobooks - Experience the joy of being told a story
eqMac 2 - The open-source macOS audio optimizer 🎛️
Bound - Prose fiction built for mobile.
Boom 2 - Boom is a simple volume booster that lets you boost the volume of your Mac and your music files.
Prologue - Audiobook player on iOS for Audiobooks hosted on a Plex media server