Booming Cords

You begin performing a song of crashing power, sending waves of devastating sound outwards from your instrument. A wave of sound rolls out from you in a 30-foot cone. Each creature in the area must make a Constitution saving throw. On a failed save, the creature takes 4d8 thunder damage, is deafened, and has disadvantage on its next attack roll until the start of your next turn. On a success, the creature takes half as much damage and suffers no other effects.

You can create such a sound wave as your action on any turn until the spell ends.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8 for each slot level above 5th.