The Subsonics feat is extremely useful, whether it allows your spells and bardic music to be used while silenced or not.
Some bardic music (such as Inspire Courage, which is the best one) is a free action to maintain once you've started, and some of them (again, like Inspire Courage) can last all day so long as you spend a free action each round to maintain them. A good way to extend your uses of inspirational boost and your badge of valor is to use, say, Inspire Courage with Perform (Oration) so you can function without an instrument, use them both just prior to spending a standard action boosting your allies, then use Subsonics to maintain it until you absolutely must switch to another song or to cast a spell.
Huzzah!