Thunderdome

You create a translucent 15-foot-radius sphere of arcane energy centered on a point you choose within range. Inside the dome, acoustics are amplified to the point where sound can create a damaging effect. Sounds originating from outside of the dome are not amplified and the sounds from within the dome are not amplified outward above their normal volume. If the area of this spell overlaps with an area under the effect of a Silence spell or other spell effect creating noise elimination, both spells are nullified.

Speaking (including casting spells that have a verbal component), moving at more than half speed, making an attack, being hit by an attack, or the impact of an object within the dome's space all create sufficient noise to create the thundering effect. Each time a sound triggers the effect, all creatures within the dome take 1d4 Thunder damage. A creature made of inorganic material such as stone, crystal, or metal takes 2d4 Thunder damage.

Spell effects , magical item effects, and attacks that create Thunder damage or explosions that occur within the dome result in an additional 2d8 Thunder Damage to all creatures within the dome. The damage caused by Thunderdome is not considered a trigger for the additional damage.