Booming Voice

    When you cast this spell, the next thing you say booms out with the volume of thunder and all creatures within a 300 ft. sphere must make a Constitution saving throw taking 20d6 Thunder damage and are deafened. Any creatures that are allies to you have advantage on the save. If this spell is cast in a cave or some other location where sound echoes, the range is doubled and all creatures have disadvantage on the save. You are unaffected either way.

    Cast at Higher Level. For every spell slot used above 3rd adds 2d6 and extends the deafness by one more round and if you use a 7th level or higher spell slot the creatures that fail the save become blind for a number of rounds equal to 1 + your spell casting modifier.