Okay, let me clarify. This question has to do with my aliens and how they hear.
My aliens have 3 antennae, a left antenna, a right antenna, and a central antenna. Each antenna has 3 sets of sensors.
The infrasound sensors can detect sounds below 20 Hz (human threshold of hearing) miles away from the source.
The mid-frequency sensors can detect sounds between 20 Hz and 20,000 Hz (human hearing range) a few miles away from the source but not nearly as far as the infrasound sensors.
The ultrasound sensors can detect sounds above 20,000 Hz at most a few yards away from the source. This allows mother aliens to hear their babies inside the eggs. Adult aliens don't usually make sounds in this part of the spectrum.
And these aliens can tell what direction the sound is coming from as well as distance.
These sets of sensors all have their own nerves. So there are 9 auditory nerves. These nerves get bundled up in the bottom of the antennae forming 3 auditory nerve bundles. These nerve bundles in turn get bundled up into 1 auditory nerve complex.
This is where I have to mention the brain within a brain. Because so much information is being picked up by the antennae (frequency, intensity, distance from source, and direction to source), it makes sense to me to have a brain specialized for hearing within a larger brain that does all the other brain functions.
Each nerve within the auditory nerve complex branches out to every main section of this auditory brain. Then the auditory brain processes the sound and sends it to the rest of the brain. When the signal gets to the cerebral cortex is when the alien is able to figure out the source of the sound and respond to the sound.
Is this brain within a brain plausible given that there is so much information about the sound being picked up by the sensors?