Power and Intensity

• The waveform shows how sound pressure varies over time.

• Related to sound pressure are:
  1. sound power emitted by the source:
     • a fixed quantity, in Watts (W),
     • analogous to the wattage rating of a light bulb.
  2. sound intensity measured a distance from the source:
     • power per unit area carried by wave (W/m$^2$),
     • influenced by interference and environment,
     • analogous to light brightness at different positions in a room.