AudioSource, AudioClip, Audio Mixer, 2D/3D sound, music and SFX.

AudioSource

AudioClip

AudioListener

2D and 3D Audio

Audio Mixer

Volume and Decibels

Music

SFX and PlayOneShot

3D Audio and Distance

Audio Fades

Changing Pitch

AudioSource.PlayClipAtPoint

Audio Manager

AudioSource Pooling

Saving Volume

Pause and Audio

Audio Import Settings

Common Audio Mistakes

Complete Audio Manager Example