Resonance

Artificers that use magical instruments to create complex sounds and weave songs. They are known for creating a new style of music unachievable by normal instruments called Magical Dance Music or MDM for short. 

They create magical instruments that can create any song they imagine to inspire those around them. If it wasn't for their technological capabilities to create such devices they'd likely be mistaken as bards.

Tool Proficiency

When you adopt this specialization at 3rd level, you gain proficiency with 2 musical instruments of your choice. 

Resonance Spells

Starting at 3rd level, you always have certain spells prepared after you reach particular levels in this class, as shown in the Resonance Spells table. These spells count as artificer spells for you, but they don't count against the number of artificer spells you prepare.

Artificer Level                                       Spells

 

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         3rd                                                                                 Bane, Dissonant Whispers

         5th                                                                                    Calm Emotions, Shatter

         9th                                                                              Counterspell, Hypnotic Pattern

         13th                                                                                 Aura of Purity, Confusion

         17th                                                                           Circle of Power, Destructive Wave

Arcane Instrument

Your musical pursuits have led to you making instruments a conduit for your magic. As an action, you can turn an instrument your holding into an Arcane Instrument, provided you have tinker's tools in hand. You gain the following benefits while using this instrument. The instrument continues to be Arcane Instrument until you create another instrument or you die.

• You may use this instrument as a spellcasting focus.
• You may add your intelligence modifier to  performance checks made while playing this instrument. 
• You can decide what sounds the instrument makes when played and the volume.

Arcane Ensemble

You learn to amplify the music you create through items you have infused. As an action, while holding your magical instrument, you may begin a song. Each creature within 30 ft. holding an item infused by you gains a benefit you choose of the effects below. On following turns you may use your bonus action to switch the effect with one of the others listed. The song ends after 1 minute or if you become unconscious. 

• Advantage against a saving throw of your choice
• Walking speed increased by 10 ft.
• +1 AC
• May add their proficiency bonus to the first attack roll they make each turn
• May add their proficiency bonus to the first damage roll the make each turn
• Advantage on the first skill check they make each turn

You may use this ability a number of times equal to half your proficiency bonus(rounded up), and you regain all expended uses when you finish a long rest. Additionally, you may use this ability by expending a spell slot of 1st level or higher. 

Elite Composer

At 5th level, you develop masterful command of your Magical Instrument, enhancing the spells you cast through them. Whenever you cast a spell using your Arcane Instrument as the spellcasting focus, you gain a bonus to one roll of the spell. That roll must restore hit points or be a damage roll that deals bludgeoning, force, piercing, psychic, or thunder damage, and the bonus equals your Intelligence modifier (minimum of +1).

Melodic Master

Starting at 9th level, you can incorporate stronger magic into your songs:

• Whenever a creature starts its turn affected by Arcane Ensemble, the creature gains 5 temporary hit points. These temporary hit points last until the song ends.
• You can cast enthrall without expending a spell slot and without preparing the spell, provided you use Arcane Instrument as the spellcasting focus. You can do so a number of times equal to your Intelligence modifier (minimum of once), and you regain all expended uses when you finish a long rest.

Beat Drop

Starting at 15th level, you're a master at creating music beyond what others thought was possible using your Arcane Instrument:

• While you have your Arcane Ensemble active you may use an action to orchestrate a beat drop. Until the start of your next turn all creatures effected by your Arcane Ensemble have advantage on all attack rolls and their attacks score a critical hit on a roll of 19 or 20. You may use this feature once per long rest unless you expend a spell slot of 5th level or higher
• You learn a special version of the Otto's irresistible dance spell, it counts as a 5th level artificer spell for you.