According to DDOwiki:
I wonder how big chances does the enemies have to break free when beating them ... Does it depend on inflicted damage (ie: I hit for 100 and my perform is 60 ->the mob will break free) or it is just new roll on each hit to save Enthrallment ? Or it is just some sort of magically hidden chance ?This song enthralls and weakens nearby enemies, causing them to cease their activities and suffer a -2 penalty to attack rolls and Will saving throws. Damage has a chance of breaking the enthrallment effect but not the penalties.
I have tested it a bit on VetII bard , but it is not reliable source imho - I´am wondering more about 25 and EEs.
I would welcome any advice , Thanks