Crescendo

This spell creates a martial fanfare that slowly builds in volume, inspiring you and your comrades to ever-greater combat prowess.
During the first round of the spell, the horns and drums can be heard faintly, but no other effect occurs.
On the second round, as the music becomes louder and more inspiring, each friendly creature within 30ft sphere gains +1 to attack rolls.
This bonus increases to +2 in the third round, then to +3 in the fourth round as the music gets louder and louder.
Allies who move more than 30 feet away from you lose the bonus, but they regain it at its then-current level if they later step back within range.