Essentially, I have a flying predatory creature in my world which is roughly the size of a raven and hunts at night, relying quite a bit on sound for echolocation in tighter spaces, hearing for both prey and predators and for communication. Because of this, I wished to give them large ear-like structures, but there are some problems with the context the creature is in:
the creature is not from earth and has many similarities with arthropods overall, with most of its head, apart from most of these ears, being covered by a hard exoskeleton, so I didn't want to give it external ears too similar to mammalian ones.
these creatures have natural predators, so I wanted their ears to be usable to look bigger and more threatening, potentially with eye spots or bright patterns.
I wanted the ears to be somewhat compressible, both to hide said warning patterns while trying to camouflage and to make them less likely to be damaged or get in the way when not used to actively listen for something.
The solution I thought of was a flexible frill-like structure with 2 main, flexible support "rods" on each side of the head (measuring around 5 centimeters in length) that could spread out like a satellite dish, with a net of muscles on the membranous part changing the shape of the ear to further help it amplify sound at certain frequencies of interest to the alien, like what you'd see in pterosaur wings or an octopus' skin. Rough draft of what I mean below, blue being the "ear" while retracted close to the body and orange the structure spread out and in use:
That being said, I haven't really heard of anything quite like this before in our world, the closest being African elephant ears, which can't quite compress and have their sized justified in part due to thermoregulation. Other than that, I couldn't find anything really saying whether such an arrangement could actually be good or just a waste of energy.
That said, could such a type of external ear work?.
Specifying what I need: I'd like to know if it's at least somewhat functional without being terribly impractical, and whether this design could be still salvageable to some extent in case it's not.