This paper considers the dimensions of the melodic process essentially based on discrete pitches. It aims to sketch a notional framework which helps to highlight very general mechanisms that might reduce the divide in the study of musical systems, notably between the normalised system of modern Western art music and "other" systems. This aim is part of a project of bio-anthropo-musicology, the ambition of which is to go beyond a descriptive approach towards an explanatory approach of the phenomenon of music. Firstly, we will propose a definition of the principal notions allowing to describe the organisation of the field of discrete pitches through the melodic process: tonality, harmony, and modality. Secondly, we will describe the three levels of organisation in this field, stressing in particular the analysis of diverse musical productions that seem to express these levels.