Mixer: contained in a stream. Takes multiple playing sources, and adds them together into the single device audio output stream.
Source: Represents a node in the audio graph. Can either be an input node,
like a SineWave or Track, a transform node such as Gain or Repeat, or
an output node like the mixer.
As sources can have a different sample rate than the native audio stream
sample rate, the SampleConversion source is needed between the input source
and the output source/mixer.
Sound: An instance of a playing graph of sources, can be used to control the playback or modify the graph.
Sample: A floating point PCM value of the average waveform amplitude at a given slice of (1/sample_rate) time. Channels are interleaved in source
Frame: A planar collection of samples from the same point in time of all channels in the source.
Note that there may be up 8 channels of audio for any given source.