I mean, you've got to be kidding me, this script should be working.
function playerEntered(newPlayer) script.Parent:Play() end game.Players.PlayerAdded:connect(playerEntered)
Put this in a local script:
sound_id = 0 -- Put your sounds 'SoundId' here S = Instance.new('Sound', game.Workspace.CurrentCamera) S.SoundId = sound_id S:Play() script:remove()
The sound will only play one time!