Chapter 4—How Music Works, Part II: Pitch
This website provides details on the physics of music; many of the sources are constructed to answer non-specialist questions about music acoustics. Especially interesting are the discussions on harmonic singing and the physics of the didgeridoo. From the University of New South Wales.
A website for learning about the fundamentals of music. Includes explanatory material, tutorials, exercises, articles, and references. Established in 1997 by José Rodríguez Alvira; includes drills in English and Spanish.
A website for learning about the fundamentals of music. Includes animated units on notation, scales, intervals, and chords and provides exercises and tools for analyzing key signatures, chords, and various elements of rhythm.