The development of music has always been interrelated with the development of technical possibilities for composition and new formats of reproduction. Although technologies like AR and VR have been around for a long time, they are currently gaining new prominence in both every day life and professional use. This is due to new technical developments and their increasing accessibility. Today, extended realities are among those technological innovations that promise to be formative for contemporary art and music. But even though there are some great potentials for working with sound and music, it feels like auditory aspects are often just necessary by products and not the artistic starting point for AR/VR works. This lecture examines technical and artistic possibilities and limitations of AR/VR from an auditory perspective and reflects on existing approaches for extended reality in music and sound art.