Original:  The optophonic piano Wladimir Baranoff-RossinSee Baranoff-Rossin 's official web page started building his optophonic piano in the 1915s.
Revised:  The optophonic piano Wladimir Baranoff-RossinSee Baranoff-Rossin started building his optophonic piano in the 1915s.
Edit intent: clarity