What is the fine-grained topic of the following text: In his interview, America folk singer and expert Sam Hinton said, “I’ve not found a finer harmonica than that of Mr. Huang’s.” Cham-Ber, a celebrated performer in China as well as the United States, was also a popular showman in Las Vegas in the 1950s and 1960s. Only return the topic.
Sam Hinton's opinion on Mr. Huang's harmonica and Cham-Ber's career.