Smooth and melodic, yet improvised and unexpected, the eerie Carnatic music that Suhas Rao draws from his violin is only a distant cousin of the Western classical music typically associated with the instrument. A lifelong Massachusetts resident, Rao, 17, became part of the 4,000-year-old tradition of Carnatic music of India at the age of 6 when his parents encouraged him to take it up. He has since performed across the United States and India, sometimes for audiences of several thousand people. He will perform this weekend at the Lowell Folk Festival. "Music in general is just a way for me to relax and express myself," said Rao, who also plays the clarinet, saxophone and piano. "Carnatic music is something I can also use to connect with my heritage because I was born here in the U.S. so it's my strongest link." When the British brought the violin to India in the 18th Century, South Indian musicians used different tuning and hand techniques from those practiced in the West to adapt the instrument to India's Carnatic style, Rao said. Indian artists like himself are keeping the music alive and well in the United States, but Rao said some of the best reactions he has gotten are from Americans. During a performance at Westwood High School, a fellow classmate told Rao that the music was the most beautiful thing he had ever heard. "I was kind of taken aback, because I'm not a professional and it was more of a Western audience I was playing f ...