After Canary and Siren used their respective cries consecutively, it got me wondering what would happen if they both screamed at the same thing simultaneously. Maybe we'll find out next season.
Well, from a physics point of view, when two waves of the same frequency overlap and are in phase with each other, there is "constructive interference" where the amplitude is magnified. So if Canary and Siren were able to match frequencies and phases perfectly, they could create a much more powerful sonic blast. Conversely, two waves of the same frequency that are out of phase, cancel each other out. So Canary and Siren could use that effect to blast an area, while leaving a safe "dead zone" in the middle. So, yes, they could do some pretty cool things if they joined forces.