"An introduction to the basic element of music called rhythm, with some definitions."
"Understanding Music: Past and Present is an open Music Appreciation textbook co-authored by music faculty across Georgia. The text covers the fundamentals of music and the physics of sound, an exploration of music from the Middle Ages to the present day, and a final chapter on popular music in the United States."
The Free Music Archive offers free downloads under Creative Commons and other licenses.
Introduction to Music Appreciation is about listening, appreciating, understanding, and discussing music. It explores the history, aesthetics, and criticism of Western music for an enhanced understanding of the topic. Chapters include:
"SUNY OER Services offers template courses that can serve as starting points for your own development. You can mix, match, and adapt anything from the courses below quite easily.
These courses are delivered via the Lumen Learning platform, and can be integrated into your LMS (Blackboard, Canvas, Moodle) quite easily."
https://courses.lumenlearning.com/suny-coursesupport/chapter/art-and-music/