Base Duration

Refers to the the base length of time a bard song lasts for. Keep in mind this duration will sometimes vary based on your bard level, and often enhancements:
 * Lingering song enhancements grant +20% per tier, up to +60% (Spellsinger enhancements tier I ability)
 * Virtuoso enhancement grants +20% (Spellsinger enhancements 5th core ability)
 * Fatesinger epic destiny
 * Lasting Inspiration epic destiny feat