Inspection
Thankfully, it wasn't long before Rui got his hands on what he needed. The Beggar's Sect did not inquire into how he intended to use them, but he did not forget the stare from the professor as he left the Libraries of Gehu before heading to an uninhabited location where he could train without being spied on, a location he got from the Beggar's Sect as well.
Deep within a cave network in a mountain range in the Derschek Region, Rui sat down as he worked with the new toys that he got from the Beggar's Sect.
There were many parameters and phenomena related to sound that he had yet to explore. Techniques like Transverse Resonance make use of constructive resonance and superposition between two sound waves to overlap two sound waves into a single stronger sound wave.
However, there were other phenomena that could be used as the basis of new techniques.