Similar to “eye balling” something as a visual estimate, ear balling is used when trying to achieve a rough estimate of a sound. Although the word sounds dirty, it typically is not; unless you can somehow manage to stuff your nads into a woman’s ear.
Usage: “Josh had to tune the car by ear balling it before selling it to Wild Bill. He bought the car from Jill for only $20 so it was a bargain. And he’s Jewish so he knows a thing or two about bargains!”