Whining noise whether in gear or not.

There’s a whining noise coming from my car whether it’s in gear or not. It increases in frequency and amplitude as the RPM’s increase. I’ve replaced the alternator with no change. It sounds like it’s coming from a pulley on the belt but I don’t want to rip into anything else without some clues as to what it might be. I’ll be posting a video soon. Any help is appreciated.

05 mitsubishi outlander
2.4 l, 4 cyl engine
Manual transmission