• A dimensionless logarithmic unit utilized to express the ratio of two powers or intensities, such as voltages, currents, or sound intensities. The number of decibels is equal to 10 times the common logarithm of the ratio of the measured powers, or when comparing voltages, currents, or analogous acoustic quantities, it is 20 times the common logarithm. It is equal to 0.1 bels, or approximately 0.1151 nepers.
  • In acoustics, the sound pressure ratio that determines the relative intensity of sounds, against a reference pressure. Such a pressure is usually defined as 20 micropascals, which is assigned a value of 0 decibels. Anything above this 0 decibels threshold is considered to be audible. Before pain sets in, a person with good hearing can listen at 120 decibels, or 20 pascals, which is a trillion times louder than 0 decibels.
  • chemical symbol fordubnium
    (written as Db)
  • synonymdecibel