Engine Noise

https://youtube.com/shorts/xVCDi8AGHoU?si=zBDugOMZxWigPU-l

This started about a week ago and has got worse. It went from being intermittent to being mostly constant now. The camera definitely picks up the noise better than my ears, but it’s noticeable if driving with windows down.
Any ideas on what it could be? Sounds like it’s coming from under the vehicle, doesn’t change at all with clutch depressed.
I tried briefly to open the hood and see if it was coming from any of the pulleys, but I couldn’t pinpoint the location.

I’ll investigate further when I get back from a business trip, just wondering if anyone had any pointers or leads.

 

Sounds like flat sheet metal vibrating against something.

Does not sound like a bad pulley or any rotating component becuase the noise doesn't follow engine rpm smoothly.

It's a resonance noise that gets excited at certain frequencies (rpms) and less so at others.

Check bolts (bolt tightness, or missing bolts) on skid-plate(s).
Check bolts on catalytic converter heat shield(s).
Check bolts on front wheel dust shields.

 

That makes sense. When I hear it with the windows down I can hear a “chirp” occasionally when the engine load abruptly changes even if it wasn’t already in the resonant range.
I just did the 90,000 Mx interval, replaced 3 joints and carrier bearing and a front hub assembly … sounds like I probably left something loose.
I’ll report back what I find in a few days.

 

I don't know I'd rule out pulleys from the sound in the video. If it were me, pulleys would be on the list of things to check (especially because its so easy to do so).