Ballad of Battle

You inspire your allies through song creating an aura of rousing music that extends 30 ft from you and moves with you. The aura grants friendly creatures in the area that can hear you a +1 bonus to attack rolls. When a friendly creature in the aura other than you makes an attack roll, you can use your reaction to grant them advantage on the attack. If the attack hits it deals an additional 1d8 thunder damage. You must use this reaction before the attack hits or misses.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for every two slot levels above 2nd. Additionally when you cast this spell using a spell slot of 4th level or higher, the attack bonus increases to +2. When you use a spell slot of 6th level or higher, the attack bonus increases to +3.