Your innate magic comes from the harmonies or dissonance of the multiverse itself. Most often, sorcerers with this origin find themselves hearing sounds or feeling movements they cannot explain: a dance creatures happen to be in, a musical chorus that exists in the world itself, etc. Acoustic sorcerers hear the frequencies and feel the vibrations that permeate all of creation. Any given sorcerer could be the first of a new bloodline, as a result of unique alignment of the multiverse or one born in a place of intense reverberation.

Heightened Senses

Starting at 1st level, you gain tremorsense to 20 feet.

At 3rd level, you may focus your senses briefly to gain blindsight up to 60 feet for up to a number of minutes per day equal to your Charisma modifier (minimum of one) in one minute intervals.  You regain all uses of this feature after you complete a long rest.  

Acoustic Magic Spells

You learn additional spells when you reach certain levels in this class, as shown on the Acoustic Magic Spells table. Each of these spells counts as a sorcerer spell for you, but it doesn’t count against the number of sorcerer spells you know.

Whenever you gain a sorcerer level, you can replace one spell you gained from this feature with another spell of the same level. The new spell must be a divination or an enchantment spell from the sorcerer, warlock, or wizard spell list.

Acoustic Magic Spells

Amplification

At 6th level, you learn to amplify your spells that deal thunder damage to be even more devastating.  When you deal thunder damage with a spell, you may add your Charisma modifier to one damage roll of that spell.  Additionally, you may also spend 2 sorcery points to force any one creature that has suffered thunder damage from one of your spells to make a Constitution saving throw or be deafened until the start of its next turn.

Base Boost

At 14th level, your connection to the frequencies and sounds of the multiverse strengthen, granting you resistance to thunder damage.  In addition, when you take damage from an attack you can see or hear, you can use your reaction to create a soundwave barrier around yourself to absorb the damage from the attack. You gain a number of temporary hit points equal to your twice sorcerer level + your Charisma modifier absorbing the damage from the attack.  This shield lasts for 1 minute, or until it is reduced to 0 hit points.  If this damage reduces the shield to 0 hit points, you take any remaining damage.  You may do this once per long rest.

Sound Soul

Starting at 18th level, you can spend 6 sorcery points as a bonus action to magically oscillate your very form. In this state, you gain a flying speed of 60 feet, you can move through other creatures and objects as if they were normal terrain, and you gain an aura that extends out to 10 feet that gives 5 temporary hit points or deals 5 thunder damage to any creature in it (your choice).

You remain in this form for 1 minute. It ends early if you are incapacitated, if you die, or if you dismiss it as a bonus action.