Avinash Balkrishna Patwardhan born 30 August 1953 in Nagpur, Maharshatra (India) is a civil engineer and a law graduate who has profound knowledge and interest in Indian classical music. He is the first person in recent centuries to unveil and demonstrate the Sarana Chatushtai as originally suggested by Bharata Muni in the Bharata Natya Shastra which is the only way to obtain 22 srutis (notes useful to music) on a musical instrument. He started his career as an engineer with the state government of Maharashtra. Later he went into teaching civil engineering and eventually joined social work. He was a part of the Knit India movement (1985–1988) and Narmada Bachao Andolan (1998-1993) with late Baba Amte. He also worked with Dr. Vikas Amte for Earthquake Relief at Killari, Maharashtra (1993–1994). He started his research on Indian classical music in the 1990s which led to his work on the Sarana Chatushtai and later he also evolved a methodology to develop perfectly tuned flutes.
Avinash Balkrishna Patwardhan's research on Indian classical music led to the successful demonstration of the Sarana Chatushtai in the year 1998. This was the first time in many centuries that this has been actually proved subjectively and objectively on flute as well as a stringed instrument. Other than Bharat Muni, him and probably Sharang Dev, there is no evidence of any other musicologists realizing the existence of srutis as per Bharata Natya Shatra. His work has been acknowledged by music experts and he has also presented a paper on the same at ITC Sangeet Research Academy, Calcutta, India at the National Symposium on Acoustics (1998). This demonstration proves incorrect, the assumption by Pandit Vishnu Narayan Bhatkhande, who has criticized the concept of existence of srutis itself in his book Bhartiya Sangita Paddhati [Vol 2] (written in the late 18th or early 19th century).