What's the difference between Martin guitar and Martin Smith guitar?

Martin is a legendary guitar brand, and its timbre makes people want to stop. The only thing Martin Smith's guitar and Martin's guitar have in common is the word Martin in the name, and nothing else has anything to do with it, just like there is an old word in San Francisco and flea market, or the fortune tellers under Andy Lau and Liutouqiao are all surnamed Liu, Obama and Oreo.