The Audio Mixer is an Asset that can be referenced by Audio Sources to provide more complex routing and mixing of the audio signal generated from AudioSources. It does this category based mixing via the AudioGroup hierarchy that is constructed by the user inside the Asset.
DSP 效果和其他音频母带制作概念可应用于音频信号，因为音频信号是从音频源路由到音频监听器 (AudioListener)。
音频路线规划是指获取一定数量的输入音频信号并输出 1 个或多个输出信号的过程。这里的“信号”一词指的是连续的数字音频数据流，可以分解为数字音频声道（比如立体声或 5.1（6 声道））。
Internally there is usually some work on these signals being done, such as mixing, applying effects, attenuation etc. For various reasons that will be covered, this is an important aspect of audio processing and this is what the Audio Mixer is designed to allow you to do.
With the exception of Sends and Returns (which will be covered later), the Audio Mixer contains AudioGroups that allow any number of input signals, mix those signals and have exactly 1 output.
在以前版本的 Unity 中，不存在路线和混音的概念。用户以前可以将音频源放置在场景中，并且音频源产生的音频信号（例如通过音频剪辑）被直接添加到音频监听器，所有音频信号在一个点上混合起来。此处需要注意的是，这些操作与场景图正交进行，无论音频源在场景中的什么地方。
Audio Mixers now sit between the AudioSource and the AudioListener in the audio signal processing space and allow you to take the output signal from the AudioSource perform whatever routing and mixing operations they wish until finally all audio is output to the AudioListener and is heard from the speakers.
某些声音概念与场景图和 3D 世界有关。其中最明显的是基于 3D 距离、与音频监听器的相对速度和环境混响效果进行的衰减应用。
As these operations are related to the scene and not to the categories of sounds in an Audio Mixer, the effects are applied at the AudioSource, before the signal enters an Audio Mixer. For example, the attenuation applied to an AudioSource based on its distance from the AudioListener is applied to the signal before it leaves the AudioSource and is routed into an Audio Mixer.
As stated above, Audio Mixers allow you to effectively categorise types of sounds and do stuff to these categories. This is an important concept, because without such categorisations, the entire soundscape quickly becomes a mess of indistinguishable noise as every sound is played back equally and without any mixing applied to them. With concepts such as ducking, categories of sounds can also influence each other, adding additional richness to the mix.
The Audio Mixer can be used effectively to create moods within the game. Using concepts such as snapshots (explained later) and other different mixers within a game, the game can transition its mood easily and emote the player into feeling what the designer wishes, which is super powerful in the immersion of the game.
The Audio Mixer is used to control the overall mix of all the sounds within a game. These Audio Mixers control the global mix and can be seen as the static singleton mix that sound instances are routed through.
In other words, the Audio Mixers are always present through the lifetime of a scene, and sound instances are created and destroyed as the game progresses and play through these global Audio Mixers.
Snapshots allow you to capture the state of an Audio Mixer, and transition between these different states as the game progresses. This is a great way to define moods or themes of the mix and have those moods change as the player progresses through the game.
Snapshots capture the values of all of the parameters within the Audio Mixer;