1. Object: A musical instrument is a physical object, distinct from the performer. This can include a wide variety of objects, from traditional string, wind, and percussion instruments to electronic devices and even the human body.
2. Action by Performer: The sound of a musical instrument is produced by the actions of a performer. This can involve playing, striking, blowing, or otherwise interacting with the instrument.
3. Sound Production: The result of the performer's actions is the production of sound. This sound must be audible to the human ear, although the specific range of frequencies and volume can vary greatly among instruments.
4. Musical Qualities: The most crucial aspect of a musical instrument is that its sound possesses musical qualities. This means the sound can be perceived as pleasing, expressive, or otherwise artistically valuable. The specific musical qualities of an instrument depend on its design, materials, and the skill of the performer.
It is important to note that the definition of a musical instrument can be quite broad and encompass a wide variety of objects. Some traditional musical instruments may not strictly meet all of these criteria, and new technologies continue to push the boundaries of what is considered a musical instrument.