The object of a hearing test is to measure the softest sound you can detect (threshold) for tone and speech. An audiogram is a graphic representation of audiometric data and shows your hearing ability compared to a normal hearing range. Vertical lines on the audiogram show pitch and frequency, the horizontal lines show loudness and intensity. The zero decibel shown at the top presents a barely audible sound, each line below presents a louder sound. Each test frequency is marked on the softest sound you have responded too.