INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 06, JUNE 2021 ISSN 2277-8616 Ragadist: A Method For Quantifying Raga Similarity Vinuraj Devaraj Abstract: Raga Similarity had been a topic of fascination among Karnatik music followers. Though the topic remains active and interesting, a lack of appropriate similarity quantification method leads to subjective interpretations which in turn can be ambiguous intermittently. In this paper, we propose a raga similarity method, RagaDist, that quantifies similarities between raga pairs, based on their semantic structure and classifies the similarity into a 4- scale measure. Similarities derived using RagaDist is compared with popular string similarity methods using clustering approaches – Hierarchical clustering and Partition Around Medoids (PAM) and Multi-Dimensional Scaling (MDS) methods to analyze emerging patterns and characteristics among Melakarta raga similarities. Empirical measurements were conducted using one-way ANOVA and post hoc analysis. We also determined that using RagaDist, a threshold of 0.79 may be used as a cut off to distinguish ragas based on similarity. Index Terms: Multi-Dimensional Scaling, Correlation Analysis, Clustering, Partition Around Medoids (PAM), Levenshtein distance, ANOVA, Karnatik Ragas. ———————————————————— 1 INTRODUCTION KARNATIK Music is an ancient, sophisticated yet refined art form of delivering mesmerizing music through a structured In its core, Karnatik ragas are based on sapta swaras or seven method. This form of art is predominantly practiced in South musical notes viz. ―Sa‖, ―Ri‖, ―Ga‖, ―Ma‖, ―Pa‖, ―Dha‖ and ―Ni‖. India and this form of music is still the foundation for various The figure 1 below represents solfeggio of Karnatik raga as musical compositions that are emerging in several forms of represented on a single octave of a piano. There are variants entertainment such as movie music production, band music, of these notes that corresponds to a flat or a sharp note folk songs etc. The heart and soul of Karnatik music is the expect for ―Sa‖ and ―Pa‖. raga, which is a sequence of musical notes that defines the boundary within which a musical piece must remain. Once a musical composition adheres to a raga, the underlying patterns, motifs, and variations must remain within the structure defined by the raga. This may seem like a constraint but in reality, this constraint has produced several beautiful compositions in Karnatik music. The constraint of staying within bounds of a raga has made music composers, practitioners and enthusiasts remain inquisitive on raga similarity – identifying ragas that are similar, so that Fig 1:Solfeggio of Karnatik Raga. appropriate sequencing of musical compositions can be made without breaking the melody sequence of a song. This Karnatik Representation Variants inquisitiveness has led to the emergence of ―Raga similarity‖ Note as a topic of discussion among Karnatik music practitioners Sa S None and enthusiasts equally. Signature similarity is a sub topic Ri R 3 variants – R1, R2 & R3 Ga G 3 variants – G1, G2 &G3 associated with Raga similarity, where the similarity between Ma M 2 variants – M1 & M2 ragas is determined based on its structure alone, keeping Pa P None aside the temporal and spectral characteristics. In a typical Dha D 3 variants – D1, D2 &D3 scenario to identify the name of a raga, once a musical Ni N 3 variants – N, N2 & N3 composition is played, a trained Karnatik musician maps the Table 1: Karnatik notes and corresponding representations frequency of various notes played to the mental map of and variants musical notes that the musician would have developed by virtue of years of training and practice. Once mapping of notes The presence of these variants ensures that there are 16 is established in the mind, musicians can put together notes in notes available from which a raga can choose its signature. right sequence and then compare the emerging sequence to i.e. A Karnatik raga will always be a combination of these list of all known ragas to decipher name of the raga. variants expect for the fact that at any given point, a raga will utilize, in principle, only one variant of a given note. Such ragas are known as Melakarta Ragas. A Melakarta raga always satisfies 2 conditions- there will always be 7 notes and there would be only one variant of a note used in its ———————————————— construction. As a result of this, a Melakarta raga is also Vinuraj Devaraj is currently pursuing PhD in Data Science in known as a sampoorna raga. The anatomy of a raga is Harrisburg University of Science & Technology, Harrisburg, PA, USA. defined by the sequence of notes structured in an ascending E-mail: [email protected] form and descending form. Its known as ―arohanam‖ or notes to be played during an ascending descending pattern of melody and ―avarohanam‖ or notes to be played during descending pattern of melody. Both these forms can again be divided into 2 parts – Poorvanga (Notes: Sa, Ri, Ga and Ma) 310 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 06, JUNE 2021 ISSN 2277-8616 and Uttaranga (Notes: Pa, Dha, Ni and Sa (from next octave)) as illustrated in Table 2: Karnatik notes, description and 2 BACKGROUND, MOTIVATION AND METHODOLOGY comparison with Piano notes. Karnatik Ragas forms the core of Karnatik Music as it is N Note C C D D E F F G G A A B impossible to illustrate Karnatik Music without ragas. In its ot description # # # # # simplest form a raga is a combination of musical notes which e when combined with timing or Thaalam, intonation, vibratos or S Shadjam gamakas, tempo or kaalam and motifs produces music that R SuddhaRis highly influences a focused listener’s mind. Ragas, if rendered 1 habham correctly, has the ability to convey emotions (Venkatesh, R Chatusruth 2010). 2 iRishabha m 2.1 Background R Shatsruthi The raga scheme in Karnatik music follows a parent-child 3 Rishabha model where there are a set of parent ragas called Melakarta m from where the child ragas, a.k.a Janya ragas are derived G SuddhaGa from. There are 72 Melakarta ragas which can further be 1 ndharam divided broadly into two group of 36 ragas each. While Group I G Sadharana contain ragas with first variant of ―Ma‖ or note ―M1‖ or 2 Gandhara SuddhaMadhyamam, Group II, contains ragas with note ―M2‖ m or PratiMadhyamam. Ragas in each group are further divided G Antara into sub groups, called as chakra, of 6 ragas each there by 3 Gandhara forming 12 sub-groups of ragas which conceptually corresponds to each energy center of human body. The m M SuddhaMa chakras are named as Aditya, Agni, Bana, Brahma, Deva, 1 dhyamam Dishi, Indu, Netra, Rishi, Rudra, Rutu and Veda. Hence this M PratiMadh whole architecture forms a two-level hierarchy as illustrated in 2 yamam the figure below. Poorvanga P Panchama m D SuddhaDh 1 aivatham D Chatusruth 2 iDhaivatha m D Shatsruthi 3 Dhaivatha m N SuddhaNis 1 hadham N KaisikaNis 2 hadham N KakaliNish Fig 2: Group of Melakarta ragas – dividing into 2 main groups 3 adham Uttaranga and 6 sub-groups under each main group Table 2: Karnatik notes, description and comparison with Piano notes In effect, all songs that strictly follows a raga scheme would either be based on Melakarta raga or a Janya raga. Once a In this paper, a methodology is proposed to quantify raga raga is chosen, the song always stays within the bounds of the similarity – RagaDist (RD), named after Purandara Dasa ragas i.e. the patterns of notes will be same as fundamental (Sriram, 1990) who’s widely considered as father of Karnatik structure of a raga. It is however allowed to mix ragas and music, and define a four-class scale to classify similarity make song sequences though each sequence of song between ragas. Section 2 of this paper illustrates background, corresponding to a raga will still be similar to the fundamental motivation and proposed methodology to quantify and classify composition of notes. Hence understanding similarities similarity. Section 3 illustrates analysis and results of between ragas becomes an important problem to be solved comparison of RagaDist with other string distance and it would be highly beneficial when it comes to composing measurement methods. This section also compares outcome music. of clustering methods and multi-dimensional scaling (MDS) with the proposed RagaDist method. Section 4 of this paper 2.2 Motivation offers additional insights from the analysis with a proposed Karnatik Music is an art form of singing though it can be direction on what future work looks like. IJSTR staff will edit played on other musical instruments like violin, veena, and complete the final formatting of your paper. mandolin etc. Yet, singing remains the default choice since, a trained human vocal cord can achieve supreme levels of 311 IJSTR©2021 www.ijstr.org INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY RESEARCH VOLUME 10, ISSUE 06, JUNE 2021 ISSN 2277-8616 vibrato rendition that no other instrument – wind or string, specific problems in the learning process of Karnatik music, it could mimic. Karnatik Music is taught in a ―problem-solving‖ can be observed that there are not enough studies covering manner where each stage of learning is associated with a raga similarities which is a fundamental problem that students problem to be solved. The learning starts with the problem of or experts equally runs into i.e. to identify ragas that are identifying notes or swaras where a student is trained to sing a similar or dissimilar. While students would like to know about particular note within a particular octave or sthayi and timing or similar ragas to expand their knowledge of horizon, experts thaalam, where the student is taught to render a musical note would rely on this knowledge to determine an acceptable at particular intervals of time or kaalams.