Audio Recording

In class we have been learning on working with audio and using an audio mixer to change the decibels of different sound clips. When I was messing around with the mixer I noticed that the higher the decibels the more static is put into the clip which makes the audio louder and more clear. So if we had a sound clip that was too quiet we could increase electricty which would make the clip more easier to hear. This also works vice versa if the clip is too loud we can decrease the electricity which will quiet down the film and make it more clear. The actual audio itself can not be changed so if someone missed a word in a clip you would not be able to add it in. The optimal level is 0 dbs it sounds the most clear to me and with little electricity it is not as grainy.