SPXSpeechSynthesizer output volume and speaker configuration on iOS

[lukaspetrik]

Hello, is there a way to change output speakers and sound volume of SPXSpeechSynthesizer? It's only outputting audio in the top speaker on iPhone for me - similar to when you have a phone call. I would like the audio to be played on bottom speakers - loud speakers.

[kalafus]

There's no SPXSpeechSythesizer in Xcode documentation... apparently that's part of Microsoft Speech SDK.

Maybe it's using .voiceChat mode? According to Xcode documentation, AVAudioSession.Mode.voiceChat is "A mode that indicates that your app is performing two-way voice communication, such as using Voice over Internet Protocol (VoIP)." Seems like that would disable the speaker on the microphone side. Maybe there's a passthrough setting somewhere in the Microsoft Speech SDK, or maybe it's a bug in the SDK 🤷

import AVFoundation
class SpeakerController {

    var isUsingEarpiece = false

    func toggleAudioOutput() {
        let audioSession = AVAudioSession.sharedInstance()

        do {
            try audioSession.setCategory(.playAndRecord, mode: .voiceChat, options: .defaultToSpeaker)

            if isUsingEarpiece {
                try audioSession.overrideOutputAudioPort(.none)
            } else {
                try audioSession.overrideOutputAudioPort(.speaker)
            }

            try audioSession.setActive(true)

            isUsingEarpiece = !isUsingEarpiece
        } catch {
            print("Error toggling audio output: \(error.localizedDescription)")
        }
    }
}