Thunderous Pulse

An intangible, warbling and invisible ball of screaming sound shoots forth from you in a 5 foot wide line in a direction you choose. At the same time, an identical ball appears on either side of it, 5 feet away, which shoots in the same direction and parallel to the first. Each ball travels through the air for 30 feet or until it hits a creature, object, or wall, at which point it pauses.

Creatures hit by a ball must make a Constitution Saving Throw or take 3d8 thunder damage on a failed save, or half as much damage on a successful one. Deafened creatures automatically succeed on this saving throw and take no damage. Creatures that fail this saving throw have disadvantage on Concentration checks to this damage and are deafened to all sounds other than this spell until the end of their next turn. Objects and walls take full damage unless they are resistant or immune to it. 

At the beginning of each turn, each ball adds 1d8 to the total damage it causes and continues to move in the same direction for another 30 feet or until it hits a creature, object, or wall as above. Whenever one of these balls hits a wall, it moves in the opposite direction on the next turn.

This spell ends for each individual ball at the beginning of your next turn, or if it passes through an area of magical silence or anti-magic. Creatures can only be damaged once per turn by this spell, and only creatures damaged by this spell can hear the noise created by it. Creatures that can see through invisibility or have the Keen Hearing trait can perceive each ball as a shimmering and wobbling orb. Casting dispel magic will dispel only one targeted ball at a time. 

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, an extra ball of sound appears on each side (two total) for each slot level above 6th.