The Vijayanagara musicological nonet or the are a group of nine musicological treatises written during the reign of the Vijayanagara empire. These works are counted among the most important and definitive treatises in Carnatic music theory. Each of these works contributed seminally to the growth of the Carnatic music tradition. These nine works are the by the sage Vidyaranya, by Salva Gopa Tippendra, by Kallinatha, Bhandaru Vittaleshwara's commentary on the, Bhandaru Lakshminarayana's, Achyutadevaraya's and the much celebrated by Ramamatya.
The reign of Vijayanagara empire was a watershed period in the cultural history of South India, particularly the history of Carnatic music. The period witnessed the prolific contributions of numerous musicians, saints and theoreticians. By virtue of the geo-political influence it exerted, Vijayanagara had become the confluence of many religions, art forms and cultures. Society and culture went through a process of conflict and eclectic assimilation of the traditional and elite values on the one hand and the emerging folk and foreign influences on the other. There was a strong interaction between traditional and elite values on the one hand and folk and foreign influences on the other. Much of this was also the result of a reaction and revolt against emerging sociological and aesthetic trends. Even as this assimilation and nativization of the contending or opposing influences took place, traditional purity and historical continuity continued to be preserved. These cultural trends and objectives were later sustained and fostered in the several feudatory states that continued to thrive beyond the fall of the Vijayanagar empire. Some of the notable states included Anegundi, Penukonda, Tanjore, Mysore Kingdom, Madurai, Ikkeri etc.,.
A wide range of experiments and innovations were carried out in the field of instruments too. The Tamburi introduced during the period soon became the principal drone instrument. Seminal work and innovations also took place in the Vina keyboards with regard to the accordatura, tonal range and instrumental parameters. The replaced the and it's the theoretical possibilities were fully explored through mathematical schemes of tabulation. The innovation of the concept of and organization of the entirety of contemporary melodic material under its umbrella culminated in Venkatamakhin's scheme, one which continues to influence greatly the theory and practice of Carnatic music to this day. New classificatory models emerged for ragas; (upper partials), (alternative svara denomination) and (representative note) scales and intervals were tuned to be brought into alignment with contemporary musical practice.
Various melodic and rhythmic structures found their way art music. All music became and music passed into oblivion as did the and its paraphernalia. The totality of melody came to be referred to alone. The arbitrary, archaic and prolific made way for the engendered by the Haridasas. These were further refined based on the principles of the ten vital elements called .
At the height of the Vijayanagara empire great saint-composers like Purandara Dasa, Sripadaraya, Vyasaraya, Vadirajatirtha, Kanaka Dasa, Tallapakam Annamacharya and his descendants, and Nijagunashivayogi flourished. Musical forms, the, the, the, the, the, the, the, the, the and the developed and found wide currency during this period.
Throughout the Vijayanagara period, theory and musical practice kept pace with each other closely. Great musicologists like Salva Gopa Tippendra, Kallinatha, Kumbhakarna, Ramamatya, Laksmanarayana, Pandarika Vittala, Somanatha, Locana Jha and Hrdayanarayanadeva contributed to musical theory of both North and South India during this period. Tanappacharya, Govinda Dikshita and Venkatamakhin made foundational contributions from Tanjore about a century later. Each work of these scholars records a revolutionary and seminal concept or development which cumulatively resulted in modern Carnatic music. Nine musicological treatises of great significance were composed in the Vijayanagar period and these have been called the Vijayanagara or the 'Vijayanagara Musicological Nonet'.
importance lies in the fact that it is more relevant and related to modern practice than the books written prior to it. The work, spread over five chapters deals primarily with and preliminary to it, describes the for the classification of - and the different and constituting the . Similar works by other celebrated contemporaries like Pandarika Vitthala and Somanatha project a common theme, namely the description of, classification under and the enumeration of the and constituting the . Minor ideological differences can however be discerned among these works.[2]
The brings the theory up to date, rationalizes intervals and scales, introduces the concepts of (self-generating note, upper partial), and of . is established as the . It also fixes and standardizes musical intervals on the keyboard, defines the accordatura, range, preferred strings (for particular notes) etc., for a variety of stringed keyboards. It also innovates and dedicates a new keyboard to Achyutaraya. A new scheme for classifying ragas into (superior), (middling) and (inferior) on the basis of their expressive potential is also expounded in the work. It also resolves the problem of the and notes.