So, the idea started when I came across human echolocation, it turns out everyone that has hearing uses passive echolocation intuitively even without knowing it, but more interesting is people that can echolocate actively by clicking their tongues or tapping their canes on the ground, and then I saw a project for a device that is a heavy bulky speaker that you're supposed to wear on your neck and should allow blind people to have spatial perception.
So I had an idea for a blind character to have a wristband or headband(for emmitting sound in all angles) because it would be more comfortable than clicking your tongue constantly or having to carry a cane.
But it could be annoying for people around him, couln't it? The constant clicking?
So i thought about using infra and ultrassound, for a better definition up close without losing "sight" of things far away.
The thing is, humans can't hear infrassound neither ultrassound, so I though about using earpices in the inner ear that emit sound in these unaudible frequencies and then converts it to audible sound, using the structure of the outer ear in reverse to focus the sound better, it could even act as an active hearing protection against the potentially damaging sounds to the precious hearing of our blind charater, AND it could also amplify quieter sounds so he could hear things that others couldn't.
That's DAREDEVIL right there folks, with technology!
Now, the PROBLEM is that i dont't know if the speaker on a earpiece could provide tridimensional sound needed for spatial orientation.