Strange whistling noise when moving

Trying to find the cause of this, any help is appreciated. This whistling noise recently started a couple of weeks ago. It happens only when moving, when I press and not pressing the brakes, at different speeds (low whistle when going slow and a high-pitched whistle when going fast).

I recently did the following
-Installed stubby bumper
-Changed brake pads
-Cleaned throttle body

I've checked the brake pads and nothing seems to be rubbing, I've checked the hosing to make sure the throttle body is on properly. Maybe the whistling is coming from the bumper? It has a bunch of holes in it and I haven't installed the winch yet...

It only happens when moving, I've revved my vehicle and kept it at multiple points of the RPM meter, but couldn't replicate the whistling noise when at a stand still. This leads me to believe it's something on a moving part. I'm about to have my brakes checked again, just for ease of mind.

 

Wind noise maybe from new bumper?

 

I’m hoping that could be it. I just got my winch in a few days ago and I’m waiting on 650lbs springs to come in to accommodate the extra weight and the sag I already have.

 

Is it that metallic sound? It’s hard to hear completely with the exhaust. I’ve seen where the brake pad wear indicator was pushed forward on new brake pads and was prematurely contacting the rotor but I feel like that is a more obvious noise.