Downloading Soundify 1.3.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this free software for Mac is CastPeer. The application lies within Audio & Video Tools, more precisely Editors & Converters. We recommend checking the downloaded files with any free antivirus.
From the developer:
Soundify is an application that separates the vocal and accompaniment parts of music based on cutting-edge AI algorithms. Different from the traditional center-cut extraction algorithm, this AI algorithm can process both stereo and mono files, with more thorough separation and almost no loss of sound details. You can preview the original and the separated files.
You may want to check out more Mac applications, such as ImTOO iPhone Ringtone Maker, Aiseesoft iPhone Ringtone Maker for Mac or Subsonic, which might be similar to Soundify.