chevy engine whine when accelerating and gets louder as the rpm's get higher?

[BrittnyKeaney]

my 2001 chevy tahoe has an awful whining noise 5.3 v8 4wd 2001 70k miles just replaced 2 idler pullys same sound but i think it might be the ac now but its 305 $ and i dont wanna replace it if thats not it what else could it be maybe an ac ensioner pulley? any help would be great thanks