Human hearing is limited to a range of sounds. Sounds that vibrate in the following ways cannot be heard.

• too fast (pitch is too high)
• too slow (pitch is too low)
• too large (volume is too loud) (That's right. Sounds can be too loud to hear.)
• too small (volume is too soft)

The limits for these properties of sound are called:

• upper limit of audibility (highest pitch you can hear)
• lower limit of audibility (lowest pitch you can hear)
• threshold of pain (loudest sound you can hear) (Sounds louder than this produce pain instead of hearing.)
• threshold of hearing (softest sound you can hear)

Different animals have different hearing limits. A dog whistle demonstrates this difference. It produces a pitch that is too high for people to hear, but dogs hear it easily.