So to simplify his power, it would be "the manipulation and creation of sound waves. The relic allows him, as a secondary effect, to create ultrasound waves to bolster his echolocation skills." He can amplify or decline the volume of sounds, but only if the sounds around him are not disruptive and non-rhythmic (such as someone suddenly screeching in the middle of a crowd), and he is not distracted while in the process; volume manipulation will need a significant amount of focus to make it work, and if he gets interrupted, he has to start all over. Sound good or does someone have a problem still?

My only problem is the loud sound blasts that I like, but that would be an advanced move later on, when he can control sound waves more minutely, such as concentrating most of the of the sound wave into moving into one direction (since sound waves typically travel all around), so that his ears are not as affected, but that's up to Sparky to decide if he could even have that to begin with.