Sound Waves

• Sounds waves travel through the air to the inner ear. The vibrations are converted to electrical energy. Nerves in the inner ear send these electrical signals to the brain.
  
  

Audible Sounds

• The range of audible sounds is from the threshold of hearing to the threshold of pain, i.e. the quietest sounds you can hear to the loudest sounds you can tolerate. The outer and middle ear can amplify low-intensity sounds and protect the ear against very loud sounds by reducing the sensory response.
  
  

Sound Intensity

• The loudness, or intensity, of sounds is measured in decibels (dB.) A quiet sound, like a whisper, measures about 20 dB. Loud music at a rock concert measures 80-120 dB. A jet engine can measure as loud as 180 dB.
  
  

Tone

• The pitch, or tone, of sound describes how high or low a sound is and is measured in Hertz (Hz.) Low tones, such as low notes played on a bass, measure between 50-60 Hz. High-pitched sounds can measure more than 10,000 Hz. Humans can hear tones between 20-20,000 Hz. The range for speech is 300-5000 Hz. (1)