ABSTRACT
This chapter deals with sounds that are made by physical methods. Sounds made by interacting with a musical instrument or other objects can be classified using the type of instrument itself or the part that is vibrating. There are a number of variations and refinements such as brass instruments and keyboard instruments. Classifying sounds rather than musical instruments is required when the sounds are not produced by musical instruments or are synthetic in sound or creation technique. Hitting things is probably the first interaction that humans made with potential sound-making objects and is the source of percussion instruments. Scraping pieces of wood, especially hollow ones with textured surfaces, needs some skill and preparation, although door hinges that need oiling can make some very distinctive sounds. Physical instruments can be controlled by a number of sequencer-like mechanisms.
