Tone chroma refers to the perceptual similarity of notes separated by one or more octaves.
Tone chroma, also known as pitch chroma or simply chroma, refers to the perceptual quality of a sound that allows us to distinguish between different pitches that have the same octave. In other words, tone chroma refers to the perception of the distinctiveness of a pitch apart from its octave.
For example, when we hear a note played on a musical instrument, we are able to identify not only the pitch of the note (e.g., A, B, C), but also its tone chroma. This allows us to distinguish between, for example, a low A and a high A played on different octaves of the same instrument.
The concept of tone chroma is important in the study of music perception and cognition, as well as in the development of musical instruments and computer algorithms for music analysis and recognition. In music theory, tone chroma is often represented by a color wheel, with different pitches assigned different colors based on their chroma.
Overall, tone chroma is an important perceptual feature that allows us to differentiate between pitches of the same octave, and it plays an important role in the perception and interpretation of music.