There are no damage types in D&DNext
Damage is damage, regardless of the source it is coming from. However, magical attacks, monster abilities, and magic items can have attacks that are save-resist type attacks against a particular stat.
For example, Burning Hands
Casting Time: 1 action
As you hold your hands with thumbs touching and fingers spread, a thin sheet of flames shoots forth
from your outstretched fingertips. Each creature in a 15-‐foot cone must make a Dexterity saving
throw. A creature takes 3d6 fire damage on a failed save, and half as much damage on a successful
The fire ignites any flammable objects in the
area that are not being worn or carried.
At Higher Levels: When you cast this spell using
a spell slot of 2nd level or higher, the damage
increases by 1d6 for each level above 1st.
Additionally another way to model what you are looking to have your item do is by having it apply a status effect upon hitting the target.
For example, Deafened
A deafened creature automatically fails any
ability check that involves hearing.
• A stunned creature cannot move or take
• The creature automatically fails Strength and Dexterity saving throws.
• Attack rolls against the creature have
If I were to make Sonic blast bomb trying to achieve what you've described I would make it a Con-Save Attack. Creatures that Fail to save take 2d6 damage and are deafened (Save Ends). Creatures that pass take 1d6 damage.