This ambitious young singer-songwriter and multi-instrumentalist has put out four albums over the past four years. His first solo release, “A Sun Came,” had Celtic, Indian, Middle Eastern, and other influences. On his second record, “Enjoy Your Rabbit,” he added electronic elements and structured the album around the signs of the Chinese zodiac. His third release, “Greetings from Michigan: The Great Lakes State,” paid homage to his birthplace. He plans to follow up this album with a record for each of the fifty states. In the midst of that Herculean task, he recently released a stripped-down and moving record called “Seven Swans,” which was recorded back in 2002. Stevens kicks off the long Fourth of July weekend with an outdoor show at the South Street Seaport. With the melancholy, elegantly arranged pop of the Silent League.