Controlling how much noise sound sources makes is fairly implausible. Unless you can magic forth cushioning/amplifiers, that is. But that would fit in under air magic more than sound.

It would make sense for him to be able to focus on certain sound frequencies, but even with excellent focus on a certain frequency, a loud noise on another frequency would be disruptive.

We recommend that the relic somehow helps him provide with a secondary source of sound to be used for echolocation. Probably in the ultrasound ranges.

Also, later if you want to have the power expand to be more powerful, perhaps have him get understanding of resonances in materials (like singing to make glass vibrate until it breaks. That'll allow you to use sound as a full-scale weapon.

@Ink Berry: Illusion is a field of magic that has very dangerous potential if used right. Alone its dangerous. Together with more offensive magic, its extremely dangerous. Maybe expand to also illusions into smell and such?