Maybe a ghost whistle, doorbell, swannee whistle, kazoo combination
HAN: There's another ship coming in.
LUKE: Maybe they know what happened.
OBI-WAN : It's an Imperial fighter.
LUKE : It followed us!
SPOCK : Scanning, indications negative at this time.
The Death Star itself is a Magic 8 Ball. Giving the standard replies to dialogue when comedy demands it.