Freaks out over loud sounds

I have one boy that completely melts down with sudden loud sounds ie: when his brother let's out a sudden loud scream he will freak out, come straight for me and cry. This only happens when it's a sudden sound, he is fine with things like the mower or motorcycle. It's the strangest thing. Anyone else have one that seems to be sensitive to sounds.

 

We are dealing with this too with Reece!

 

I remember this happening close to a year old for one of my LOs, then after a couple of weeks she stopped caring. Seemed like a phase. They were both scared of thunder, but when it was loud I would start going to the window and waving and saying "hi thunder" and now they don't get scared - they wave and greet it...it is pretty funny.

 

I remember Annabella did this when dh was riding the lawnmower. She didn't do it again. I think it's just a phase. Could it be that he is just suddenly startled?

 

I have a sensitive boy like that, too. It's the dog's barking that freaks him out.