I grew up near NAS Point Mugu and its Sea Testing Range. For many years their HH-46 SAR bird (like this one from Pax River) was used to clear the Range of boats and ships right before a missile test. I could be wrong, but isn't this a speaker (circled) for communicating with boats and/or crews on the ground?
The round things above the wheelbay apear to be taxi-lights (like your head lights in your car), the orange light is a search light and the things under the tail section should be a sonobuoy launcher.
my 5 cts
I thought it was because the noise of the rotors drowned out the engine noise, the speakers are boosted to a level just above the noise created by the rotors.
Now you can hear the engines as well as the rotors