Another ghostly moan?
In the end of the ROTJ, when Vader throws emperor down and the blue shit pours up from the shaft, we can hear three man voiced moans that mumble something unrecognisable.
It sounds like: "WHY? WHy? Why? why?..."
The moaning begins about 16 seconds after Vader gets his change of heart and picks the Palpy up.
Is this just some symbolic efect, or what?