So recently I've decided one my characters is going to look into swashbuckling with an orb in her offhand, I'm looking at caster builds, melee builds and healer builds with a sword+orb swashbucker splash for my favorite of int/dex/cha for damage with a good critical profile. So naturally I'll take Arcane Marauder, which will let me get that offhand that adds a bunch of spell power and makes me look uniquely caster-like.

And that opens up the option of taking Loud and Clear, which I'm considering for ANY build, caster focused, doublestrike/attackspeed focused or support focused, but I'm struggling to find good sources of sonic damage to make 20 sonic spellpower worth that 1 AP that it costs. What I've found so far:

Resonant Arms: Up to 6d6 sonic damage scaling with sonic spell power on critical hit.
- Moderate damage that only happens on a critical hit, okay, but is it enough to make 20 spell power worth it? Seems like I need more sonic damage somehow

Sonic Blast (and sound burst): Up to 5d2+10 sonic damage in an AoE, with a save vs Daze.
- Sure, it's a highly recommended spell because it costs very few spell points and it's a great box breaker, has good CC and the damage is good below level 10ish, but the damage seems like the least important part of this skill and drops off quickly. It's also the only skill effected by spell power.

Shout/Greater Shout: up to 20d3+60 sonic damage in a cone, save vs daze.
- Seem to be similar to sonic blast, but with damage that is relevant a little longer and a mana cost that's much higher. Seems to me a build based on sonic damage spells would have rather low damage in general.

Scion of the Feyworld: 2d20 sonic damage on weapon attacks, scaling with spellpower
- Got to wait until level 30 to take this, then it's only 2d20 damage on hit and is competing with a bunch of other very good level 30 feats. Besides the fact that I'd usually be planning to TR at 30, is even this enough to make sonic spellpower worth it?