I have a few questions about the lullaby spell - it affects creatures in a 10 ft radius area and can be maintained with a concentration check. Do creatures that made their save have to continue saving each round that the spell is being maintained, if creatures move out of the radius of the spell do they become unaffected, and how would the answers to these questions pertain to the Dreamspun Sorcerer Bloodline ability to have the spell automatically last for 1 minute?
As a DM of 5 years, I have never had a player play a bard (who lived long) or cast a spell like this, so I am a bit ignorant in this area of magic.