Song of Annoyance (3.5 Bardic Music Addition; PEACH)

[John Cribati]

This is an idea that popped into my head a while back. Open this in a new tab for full effect (http://www.repeatmyvids.com/watch?v=HNTxr2NJHa0&kmdom=youtube)
Song of Annoyance (Ex)

A bard of Xth level or higher with Y or more ranks in a Perform skill can use music or poetics to bother creatures within range. To bother, a bard makes a single Perform check. All creatures within 10 ft. + (5ft x Bard's Cha Modifier) must make a Concentration check against the Bard's Perform check every round or become Annoyed for that round. The effect lasts for as long as the creature hears the bard sing and for 5 rounds thereafter, or once the creature makes its Concentration Check. Once the check is made, the creature is immune to the effect for the remainder of the encounter.
An annoyed creature will be unable to cast/dispel/maintain spells or activate magic items (other than potions or oils), and takes -5 penalty on all attack rolls and Skill checks. In addition, an annoyed creature within attacking range of the Bard must make a DC (15+ The Bard's CHA Modifier) Will save or else target the Bard with as many attacks as it can. At the Bard's discretion, he may grant as many creatures as he wishes immunity by taking a -2 penalty on his Perform check for each creature to whom he grants immunity.

So... I have no head for game balance: How powerful is this? Best choices for X and Y? Is this even really necessary?

[Isair]

Well, personally I think a -5 penalty is too strong. A -2 would be more accurate, in my opinion.

As for the rest, it seems to balance itself. Making a Concentration check may not be much chance against a Perform check, but in order to avoid being attacked by friendlies, the Bard must always provide immunity to someone, thus reducing the Perform.

Given its effects, I'd say this would require a Bard of at least 7th (if attack penalty is reduced to -2) or 10th level (if attack penalty remains at -5), since it literally robs casters of their abilities and provides a somewhat decent attack penalty to non-casting characters. As for ranks, simply add +3 to the level requirement.