What’s the difference between dB and dBA?

Both of them are used to describe sound in decibels. The human hearing system is very complicated and is tuned to be more sensitive to some frequencies than others. When decibels are A-weighted (dBA) the reported dB level has a standard correction applied to account for the typical sensitivity of the human ear. Most noise standards and policies use A-weighted sound levels to ensure they reflect the human perception of the sound.