Any way to control which audio channel AVSpeechSynthesizer outputs to?

问题

I would like to use AVSpeechSynthesizer to output sound on only one audio channel of a multi-channel surround sound setup. For example, in a 5.1 system, I would like it to output on just the right-surround channel.

Right now I have:

    let synthesizer = AVSpeechSynthesizer()
    let utterance = AVSpeechUtterance(string: "This is the right channel")
    synthesizer.speakUtterance(utterance)

...however it outputs on both the left and right channels.

来源：https://stackoverflow.com/questions/32558183/any-way-to-control-which-audio-channel-avspeechsynthesizer-outputs-to