The 1920 US CENSUS incorrectly lists them as Hermann but everything else is correct. It only lists his parents as German and him as a musician. His World War I draft registration 1917-1918 lists his birth date as 16 Oct 1875. His US Passport Application has the same birth date. It lists that his father Carl Hemmann as born in Germany and died 1905. On a 1922 passenger list for Ina and Carl Hemmenn from Le Havre to New York, it lists 101 West 56th Street, NYC. I have no idea when the son Carl died. I haven't been able to track that down. I remembered that my aunt Ina always said he was a musician and that helped me narrow it down. Let me know if any of this is of any help to you.
Mary Lou