You produce a deafening barrage of sound which emanates from a sphere centered on a point within range, and gradually increases in volume.  For the duration, you must use your action on your turn each round to sustain this spell or else it ends.  When you cast the spell, and each round for the duration, each creature within the sphere must make a Constitution saving throw.  The first round, the sphere has a radius of 60 feet.  On a failed save, a creature takes 6d6 thunder damage and becomes deafened for 5 minutes.  The radius of the sphere increases by 10 feet each round (to a maximum of 150 feet the tenth round), and the damage increases by 1d6 each round (to a maximum of 15d6 the tenth round).  On a successful save, the creature takes half as much damage and isn't deafened.

The spell also emits an earsplitting noise audible out to 6,000 feet the first round, and out to an additional 1,000 feet each round for the duration.  You may choose the sound that is emitted as long as it is sufficiently loud, for example a song, or a roar, or a crack of thunder.