Evocation [Good, Sonic]
Level: Bard 3
Components: V, S
Casting Time: 1 standard action
Range: 50 ft.
Area: 50-ft.-radius emanation centered on you
Saving Throw: Will negates
Spell Resistance: Yes
Your heart light and joyful, you feel a sense of optimism as you launch into an inspiring melody.
You can strike up a rousing, inspirational song that temporarily boosts by 2 the effective caster level of each good-aligned divine spellcaster within range. This increase does not grant access to additional spells, but it does improve all spell effects that are dependent on caster level. Within the spell’s area, each good-aligned divine spellcaster gains a +4 sacred bonus on Charisma checks to turn undead, and each evil-aligned divine spellcaster takes a –4 sacred penalty on Charisma checks to rebuke undead.
Source: Spell Compendium, page 117. Originally published in Complete Adventurer, page 152, with a much larger radius.