Unfortunately, due to his lack of ability to be able to objectively measure the frequency of the sound that he produced, he would need to rely on trial and error to a large degree. Furthermore, unlike when he was creating the Flux Earther technique, it would be much more difficult to observe the success or failure of his trial-and-error method.
Since the technique involved constructive superposition of two sound projectiles, he would necessarily need to release two sound projectiles of different speeds.
The first projectile would be the Sonic Bullet technique which moved at the speed of sound, and the second technique would be the Mighty Roar Flash Blast technique, which moved faster than the speed of sound. He would need to use both those techniques and ensure that he timed and placed them and ensured that they were in phase with each other such that they would engage in constructive superposition.