Amulet of Amplification

When the player wears this amulet they can cast a cantrip "Amplify" as a bonus action that amplifies their voice once per short rest. 
Amplify uses the player's voice and has an area of effect of 25ft in a cone shape from the wearer. 
The cantrip has a chance of making enemy targets "Frightened" when used (Constitution saving throw 8+STR modifier).
Enemies in range must roll the constitution saving throw at the start of each of their turns to see if they are no longer frightened.
The wearer does not need magical capabilities to use the necklace but must have a strength score of at least 15.

Frightened

• A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within line of sight.

• The creature can’t willingly move closer to the source of its fear.

• The creature must roll a const saving throw (8+STR modifier) at the start of each turn or remain frightened.