Tongues of Seven Thunders

You speak into your cupped hands and then thrust out your arms as if throwing your voice to the creatures before you. A loud boom of thunder emits from your hands and can be heard from up to 300 feet away. Each creature in a 30-foot cone that can hear you must make a Constitution saving throw. A creature takes 7d4 thunder damage on a failed save and is deafened until the end of your next turn, or half as much damage on a successful save and is not deafened. 

At Higher Levels. When you cast this spell using a 3rd- or 4th-level spell slot, the damage increases to 7d6. When you cast it using a 5th- or 6th-level spell slot, the damage increases to 7d8. When you cast it using a 7th- or 8th-level spell slot, the damage increases to 7d10. When you cast it using a 9th-level spell slot, the damage increases to 7d12.