I tried making an "armor stand jump scare" with the playsound command, and I didn't hear anything, but in the chat it said that it sucsessfully played the enderman death sound. The subtitles didn't show anything. When I kill a normal enderman I can hear the sound.
Does this work with this command :
Because of MC-81025, you can't know if you are using a correct sound name (the console still log a WARN about that). Some of the sound path changed in 1.9, here is the complete list : http://pastebin.com/YZ6KXE9D