Quote:
Any spell whose descriptive block contains a Range entry that specifies an area effect, but which does not specify a range at which this area can be targeted, should be assumed to have a range of self. For example, the Rebuke spell, has a radius of 10', whose targeting location is self; despite the self not being explicit in the textual description of the spell.
The Adaptation does not specify a range, so becomes Self (10').
When you look through adaptations for other spells, Captivating Melody is worded that way specifically.
Reference Examples:
Alarm; specifically increases existing radius.
Arc of Lightning; lists range and target.
Awe; change to cone (above errata applies making it Self (15' Cone))
Blood Boil; specifically increases existing radius.
Breath of the Dragon; change to arc (above errata applies making it Self (10' Arc))
Castigate; specifically changes to 30' (10'r)
Crushing Weight; specifically changes to 20' (10'r)
Elemental Bolt; specifically changes to 30' (10'r)