Songs that are already active on a character prior to the activation of Soul Voice must be replayed to receive the effects of this ability.
Soul Voice primarily affects song potency, but not song duration. To increase song duration, Troubadour may be used. The effects of Soul Voice and Troubadour can be combined.
To extend the "duration" of Soul Voice, recast your chosen songs prior to Soul Voice wearing off. Even after Soul Voice wears off, the effects of your "supercharged" songs will remain, until the songs wear off or are recasted again.
/ja "Soul Voice" <me>
Since Soul Voice is a two hour special, some people prefer not to make a macro for it to prevent unintentional activation.