A little sound during reverse on my 2008 Lancer

Just wondering do you guys hear any weird small sound when you reverse on the 2008 Lancer?
 
I know there is a sound when I put the car on 1st gear then it will go away
 
Just curious about the reverse sound. if you know this problem please answer me back?
Thank you

Whats it sound like?

It's a " Clack" sound when I step on the break a little but not all the way to the floor.
it couldn't be the pads or rotors they all brand new.
 no problem when im on the highway just reversing and moving 2 mph forward then I tap my breaks LITTLE it will have this "Clack sound"
 
do you think it is serious?

The whole car is brand new, Id chalk it up to it just breaking in.

Thanks my friend said the same thing. If it was the breaks the car won't be stopping well on high speed but it stop right away when I wanted to stop immediately.