You were born without vocal cords, but still had a space for them.

(Change Hero Name to A Sound-Related name. Or A Vibration related name)

This allowed your father to have his best and brightest scientists and experimenters come up with an actual robotic voice box. This voice box was implanted directly into that space which should've held your vocal cords, and attached to the surrounding area.

But, however, the voice box had been programmed to learn from its user's memory, and could actually be adjusted consciously, which allowed you to really FUCK with everyone. You became an excellent ventriloquist, but that got you into a heap of trouble. So, you were put into a surgery so it might be modified so it was programmed to only do your voice, which had been pieced together from a bunch of other voices, making it unique to you.

But, somehow, as most backstories go, the surgery went horribly wrong. Some douche-nozzles came in, took your father at gunpoint, forcing him into a car until the other assholes made sure nobody was there.

The lead surgeon, who was your father's best friend and the inventor of your voice box, put the place on lock-down. Then they proceeded with a modified surgery.

They added an amplifier and upgraded your mimicking abilities. Now you could do the whole vibrating spectrum. Hell, you could now make people shit their pants from the brown note. They basically weaponized you in order to save your father.

When you woke up, you managed to get it somewhat under control, after accidentally killing everyone in that room and literally shouting a door down. This alerted them to your presence and they shot your father.

This made you fly into a blind rage, killing them all. You swore to avenge him by not allowing others to go what you've gone through.

(I know this is a very stereotypical story line, but hey, we have to start somewhere, yeah?)