rogerwang/node-webkit — pull request #2289 by jtg-gg (2014-09-03 01:34:47+00:00)
Title: [Notification] OSX, disable the default sound

as requested by many user https://github.com/rogerwang/node-webkit/issues/27#issuecomment-53625018
I agree with them, the notification sound can be played using audio api