AudioChannelMix

AudioChannelMix[audio] mixes channels of audio by averaging and returns a center-panned stereo audio object.

AudioChannelMix[audio, desttype] mixes audio channels into the specified desttype.

AudioChannelMix[video, ...] mixes audio channels of video.

Examples

Mix multichannel audio to mono:

audio = ExampleData[{"Audio", "Apollo11"}];
AudioChannelMix[audio, "Mono"]

Please visit the official Wolfram Language Reference for more details.