Bracket resonance sound on rev

When I rev my truck to around 4500rpm I get a loud resonance from what I would assume is a exhaust heat shield somewhere thats loose?

Here's a video I took:

https://youtu.be/jZr0JyiC4l0

 

Cats? Get a buddy to rev while you're down low looking/ listening

 

Yeah I listened to it while buddy was revving and it's definitely coming from the back of the engine bay near the cats

 

I'd take it into a little muffler shop. They'll find your problem real quick, they don't charge much if anything.

 

Good info, if I can't find anything loose I'll take it to a shop.

 

This will be easy to find with two people. The person under the truck can press a piece of wood, or similar, on the shield to stop the resonance to confirm.