Crackdown 2

Hidden Orbs are a light blue in colour (unlike the green agility orbs or purple driving orbs)

They tend to be (as you might think) hidden out of sight (under stairwells, down cliff faces, under a bridge etc.)

You'll be able to hear them if you're close by, or, press 'up' on your d-pad to do a radar sweep. Hidden orbs will show up on your radar for a split-second if you do this... Just like any other orbs, run into one to collect it and pop goes the chievo!

These orbs can be a little tricky to find, but thanks to the radar ping (up on the D pad) you can find these without much trouble. Simply go around the city and periodically ping the radar. If you see a solid blue dot, THAT is the Hidden Orb. Go to the blue dot and listen for the hum that the orbs give off. These orbs are often stuck in small out of way areas so just keep searching and you should find one in no time.