way to increase the amount of weapons affected by spells like sonic weapon

[Nicktacular]

im trying to get the most outta some of those spells but they seem to be kinda bad because they only effect like one weapon, are there any feats or items that increase the amount of weapons effected by such spells?

[Deox]

Reach Spell + Chain Spell metamagic feats will do the trick.

[Nicktacular]

is there no direct way other then metamagic finagling

[Seclora]

There is no way to cast a single target spell on multiple targets without finagling.
Either you talk to your GM and finagle your way to being allowed to research a mass version, or you use metamagic.

Any particular reason why you're opposed to finagling?

[Bronk]

Well, Dragonfire Inspiration does what you want, but you'd have to find a way to meet the prerequisites (if you don't already). Be a bard, have the dragonblood subtype, have your heritage be of a sonic breathing type, have inspire courage...