Hmm... don't have a db meter handy.

Daytons are great fans, and handle static pressure very well. Great choice if you have a lot of bends in yer ductwork.

Vortex is quieter per cfm, but almost twice the flow. Flow on this blower will drop rapidly as ductwork becomes more baroque.

Either way, properly tuned, neither fan should be too loud. If yer ductwork is simple, go for the vortex. If it's long and crazy bendy, go w/ the dayton, or possibly a dayton 465.