According to this article in USAToday- it's pronounced "Cone" and not "Kohn"
http://www.usatoday.com/life/movies/2008-09-08-4087110751_x.htm
Great movies!
Franklin Coen's birth name is Franklin Robert Coen.
Joel Coen's birth name is Joel Daniel Coen.
Eleanor Coen was born in 1916.
Shunter Coen was born in 1902.
Shunter Coen died in 1967.
Coen Tunnel was created in 1966.
Martin Coen died in 1993.
Martin Coen was born in 1933.
Kevin Coen was born in 1947.
Kevin Coen died in 1975.
Noreen Coen was born in 1993.
Coen Cuserhof was created in 1908.