Howl [two-actions] Spell 7

You let out a powerful ululation full of psychic resonance that compels others who hear it to join in. You deal 7d12 sonic damage and 1d8 persistent mental damage to other creatures who can hear within the area. Targets must attempt a Will save. The persistent mental damagea creature takes from this spell increases by 1d8 if at least one other creature is howling. A howling creature can't use auditory actions or cast spells except for those with the subtle trait for 1 round. Calculate the persistent damage after all creatures attempt their saves.