• Unity needs sounds to come from Audio Sources. The sounds are emitted and then heard by the Audio Listeners.
• Audio Listeners are most commonly connected to the main camera.
• Unity simulates sound distance/position based on the listener.
• The Doppler Affect can also be simulated.
• You can calculate echoes with Audio Filters.
• if there are certain areas you want to have a strong echo, you can add a Reverb Zone.
• Audio Mixer lets you mix different audio sources, add effects to them, and perform mastering.
• Audio mixers are an asset, you can make more than one and have many running at once.
• You can capture the settings of all the parameters in a group as a snapshot.
• You can create a list of snapshots. You then can transition between them in gameplay to create different moods or themes.
• Ducking allows you to alter the effect of one group based on what is happening in another group. (Like turning down music volume when you’re shooting).
• The asset contains all AudioGroups and AudioSnapshots as sub-assets.
• The hierarchy view contains the entire mixing hierarchy of AudioGroups inside the AudioMixer.
• The AudioGroup Strip View shows an overview of an AudioGroup, including volume settings, Mute, Solo and Effect Bypass settings and the list of DSP effects within the AudioGroup.
Most information was gotten from the Unity Audio Manual