Our old Unity plugin 'Mundo Sound - Audio Manager' has been deprecated on April 2025.
Considering it was last updated on Apr 20, 2016 (using Unity 5.3.0), newer versions of Unity probably don't support it anymore.
If you have the asset files, documentation is available on the included .PDF file.
If you have any questions regarding the plugin, don't hesitate to contact us.
Thank you for your interest!