Lyric Spell( Complete Adventurer, p. 113)
You can channel the power of your bardic music into your magic, allowing you to expend uses of your bardic music ability to cast spells.
Perform 9 ranks, ability to spontaneously cast 2nd-level arcane spells, Bardic music,
You can expend daily uses of your bardic music to cast any arcane spell that you know and can cast spontaneously. You must still use an action to cast the spell (following the normal rules for casting time), but using the Lyric Spell feat counts as part of the spellcasting action. Casting a spell requires one use of your bardic music ability, plus one additional use per level of the spell. For example, casting a 3rd-level spell requires four daily uses of your bardic music ability.
Any spell that you cast using the Lyric Spell feat gains your instrument as an additional arcane focus, if you use one. You cannot use Lyric Spell to cast a spell improved by the Silent Spell metamagic feat