Form in the modern era
Solid form is the origin of all freedom.
A composer determines the form of the music freely, selecting existing templates or consciously avoiding them. Very free elements often require a well-defined form in order to work well. Technology has expanded the concept of form to include the spatial dimension. Some of the form of a composition may be determined by which direction a sound is heard from and what the spatial impression created by the work is.
Elements of music
Musical eras