
Are |

Silence is a fairly special case. For it, the Will save and SR only apply if the spell is centered on a creature or on an item in a creature's possession. If it's centered elsewhere, then there's no save and no SR. Essentially, the save/SR is to avoid the spell being centered on you.
Fireball, however, simply tries to damage every creature in its area, and every creature in the area gets a Reflex save and applies SR if they have it. Unlike silence, fireball doesn't have special text detailing unique conditions for saves/SR.

AnnoyingOrange |

SR would work against fireball just fine.
Silence affects the area rather than the creature itself, the creature itself is not affected so much as that sound in the area is nullified, there for unless it is cast on the creature or object carried by the creature specifically SR does not apply. It is the same with a darkness spell for instance.