OFFICIAL PAGE: ISSE: An Interactive Source Separation Editor
ISSE (pronounced "ice"), an Interactive Source Separation Editor, is an open source, freely available, cross-platform software project. Although the software is an alpha version application, it is available for macOS, Windows, and Linux. ISSE allows users to annotate a time-frequency display of sound to perform single-channel sound source separation.
Screenshot courtesy of SourceForge.net