You can’t. I mean, sound based weapons have certainly popped up in sci-fi a few times, Dune comes to mind off hand (at least the David Lynch film). DARPA’s been funding research into sound based weapons for decades with a little success, though, DARPA will fund research into pretty much anything.
Throwing your voice is an old stage trick. It’s not making sound come from someplace else, but tricking people into thinking your voice is there. I don’t really know the details of how this works, so you’re going to need to do some research on that front. But, what I do know is, you’re probably going to be asking a lot more from this than is actually possible.
DARPA’s been trying to get people to design less-than-lethal weapons for years now. Sonic weapons are one of the kinds that’s made the list, but DARPA’s anything but choosy. If you’re not familiar, DARPA (Defense Advanced Research Projects Agency) is just a funding organization, and they will fund nearly any weapons technology research, no matter how bizarre. If you have an insane technology that might have combat potential, you can poke them with a stick to get funding. This results in some really weird and goofy research, like a vacuum cleaner powered, suction cup wall climber, net guns, glue guns, and of course, sonic weapons.
You can use sound in combat to distract and confuse your opponent. The best example of this is Bruce Lee, and his vocalizations in combat. Most martial artists learn to shout when striking, it help focus their strikes, and time their breathing. But, in it’s era, Lee’s technique was psychologically disruptive to practitioners. Sound can play a key role in psyching out your opponent, though, simply taking Lee’s vocalizations and bringing that into the modern day wouldn’t have the desired effect.
Now, what you’re describing, “using soundwaves to fight” would actually end up in the superpower range. There’s a couple comic book characters with exactly that power set, in fact. If you’re going for the superhero genre, then your fine. (Remembering what I said at the beginning, there’s a pretty solid interpretation of Dune that plants the novels solidly in the superhero genre.) It doesn’t mater that it’s physically impossible, it is their superpower. But it isn’t something normal combatants can do.