this is the key line to output auido in speaker instead in microphone. Note it should be set while recording
try AVAudioSession.sharedInstance().overrideOutputAudioPort(AVAudioSessionPortOverride.speaker)
Below is complete function to setup recording
private func setupRecorder() {
if isAudioRecordingGranted {
let session = AVAudioSession.sharedInstance()
do {
if #available(iOS 10.0, *) {
try! session.setCategory(.playAndRecord, mode:.spokenAudio)
}
else {
// Workaround until https://forums.swift.org/t/using-methods-marked-unavailable-in-swift-4-2/14949 isn't fixed
session.perform(NSSelectorFromString("setCategory:error:"), with: AVAudioSession.Category.playback)
}
try session.setActive(true)
try session.overrideOutputAudioPort(AVAudioSession.PortOverride.speaker)
let settings = [
AVFormatIDKey: Int(kAudioFormatMPEG4AAC),
AVSampleRateKey: 44100,
AVNumberOfChannelsKey: 2,
AVEncoderAudioQualityKey:AVAudioQuality.high.rawValue
]
audioRecorder = try AVAudioRecorder(url: fileUrl(), settings: settings)
audioRecorder.delegate = self
audioRecorder.isMeteringEnabled = true
audioRecorder.prepareToRecord()
self.recorderState = .Ready
}
catch let error {
recorderState = .error(error)
}
}
else {
recorderState = .Failed("Don't have access to use your microphone.")
}
}