Sobol, Sabol,and other variations, while not common by any means, are nevertheless found in most telephone white pages in the U.S. As far as I know no one else in the U.S. has the Soboul spelling. France is another story: there are at least 98 on one telephone listing I came across.
Victor Soboul, my grandfather, was born in France on 5 May 1851 and died at Cantrall, Illinois on 13 March 1925. Victor came to the U.S. in 1880. His wife, born in Switzerland, was Pauline Stadley (DeStadleaux?) The spelling of Pauline's surname is not clear as it is listed on different documents differently. She came to the U.S. in 1883. In any case Frank Laliron is connected to her as his Aunt lived in Paris and I have a letter from her dated in 1936. Frank came to the U.S. in 1883. I haven't been able to connect old with new: how they got here. I do know that their first child Rose Emma Soboul was born in Pennsylvania in 1886 (where??)
Victor had a brother Jacques Soboul who was living in the New York City area in 1925. He left Cantrall, I assume after Victor's death.