2-3 part book series where adults get a ringing noise in their ears that brainwashes them

Question

Main Character: The main character is a teenage boy who begins his journey running away from others that are hunting him across a bridge, they catch up with him and begin to fight and it's clear he's skilled at fighting when this happens. But an alien craft arrives nearby and they all stop fighting and begin to hide from it. He's not much for company and he's a bounty hunter type of guy in this apocolyptic world.

World Around them: Aliens have invaded killing the protagonists mother when it happened in their barn I think it was, after the invasion everyone got a ringing noise in their head that made them become like a brainwashed cog where they all walked toward a stadium and never returned. Even the kids got this ringing noise, but it wasn't strong enough to give into but gets progressively worse as they age to adulthood. The main character never had the ringing in his head and is immune like a select few.

Second Main Character: The girl they find in a crashed alien shuttle. She is an alien herself as you learn through the book and can cure the ringing noise, in the end she is shown what love is and realizes it is what her species has lost when it lost it's home world. To save her new friends that she loves she tries to get to their tower where the other aliens are attempting to stop her from touching until she is reset like an AI, so that she may once again lead them to capture all the humans.

It's a 2-3 part book series.

Answer 1

The series is called Conquered Earth by J. Barton Mitchell, with the first book being Midnight Sky, published in 2012.

Earth has been conquered by an alien race known as the Assembly. The human adult population is gone, having succumbed to the Tone---a powerful, telepathic super-signal broadcast across the planet that reduces them to a state of complete subservience. But the Tone has one critical flaw. It only affects the population once they reach their early twenties, which means that there is one group left to resist: Children.

Holt Hawkins is a bounty hunter, and his current target is Mira Toombs, an infamous treasure seeker with a price on her head. It’s not long before Holt bags his prey, but their instant connection isn’t something he bargained for. Neither is the Assembly ship that crash-lands near them shortly after. Venturing inside, Holt finds a young girl who remembers nothing except her name: Zoey.

As the three make their way to the cavernous metropolis of Midnight City, they encounter young freedom fighters, mutants, otherworldly artifacts, pirates, feuding alien armies, and the amazing powers that Zoey is beginning to exhibit. Powers that suggest she, as impossible as it seems, may just be the key to stopping the Assembly once and for all.