AudioKit v5输出问题，仅以非常低的音量传递给扬声器

如何解决AudioKit v5输出问题，仅以非常低的音量传递给扬声器

在模拟器上正常运行后，我开始在11 Pro Max上进行调试。在MandolinString上弹奏音符时，来自（11 Pro Max或8）模拟器的声音很大且清晰。在真实的电话上，声音几乎是听不到的，只能从扬声器听到。它不会转到所连接的音频扬声器，而是HomePod或AirPods。这是v5错误吗？我需要对输出做些什么？

第二个不太重要的问题是，当我实例化此对象时，MandolinString会在不调用任何内容的情况下触发。额外的推子和延迟后增益从0重置为1会抑制这种声音。

    private let engine   = AudioEngine()
    private let mic      : AudioEngine.InputNode
    private let mixer1   : Mixer
    private let mixer2   : Mixer
    private let silence  : Fader
    private let fader    : Fader
    private var pitchTap : PitchTap

    private let startTime = NSDate.timeIntervalSinceReferenceDate
    private let ampThreshhold: AUValue = 0.15
    private let ampJumpSize: AUValue = 0.05
    
    private var ampPrev: AUValue = 0.0
    private var freqArray: [AUValue] = []
    
    init() {
        mic = engine.input
        mixer1 = Mixer(mic)
        silence = Fader(mixer1,gain: 0)
        mixer2 = Mixer(silence)
        pitchTap = PitchTap(mixer1,handler: {_,_ in })
        //pluckedString = PluckedString(frequency: Float(NoteList.shared.minFreq),//                              amplitude: 1.0)
        pluckedString = MandolinString()
        fader = Fader(pluckedString,gain: 0.0)
        mixer2.addInput(fader)
        engine.output = mixer2

        self.pitchTap = PitchTap(mic,handler:
        { freq,amp in
            if (amp[0] > self.ampThreshhold) {
                self.sample(freq: freq[0],amp: amp[0])
            }
        })

        do {
            try engine.start()
            akStartSucceeded = true
        } catch {
            akStartSucceeded = false
        }
        
        DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
            // Put your code which should be executed with a delay here
            self.fader.gain = 1.0
        }
    } // init

XCode 12，iOS 14，SPM。一切都是最新的

解决方法

很可能这本身不是AudioKit的问题，这与AVAudioSession有关，您可能需要在设备上将其设置为DefaultToSpeaker。与版本4相比，AudioKit 5的自动会话管理更少，因此选择了更少的假设并让开发人员可以控制。

,

答案确实是为 AVAudioSession 添加代码。但是，它在我第一次放置的地方不起作用。当我把它放在 App 委托 didFINishLauchWithOptions 中时，它只对我有用。我在 AudioKit Cookbook 中找到了这个。这有效：

class AppDelegate: UIResponder,UIApplicationDelegate {

    func application(_ application: UIApplication,didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        #if os(iOS)
            self.audioSetup()
        #endif

        return true
    }

    #if os(iOS)
    func audioSetup() {
        let session = AVAudioSession.sharedInstance()
        
        do {
            Settings.bufferLength = .short
            try session.setPreferredIOBufferDuration(Settings.bufferLength.duration)
            try session.setCategory(.playAndRecord,options: [.defaultToSpeaker,.mixWithOthers])
            try session.setActive(true)
        } catch let err {
            print(err)
        }
    
        // Other AudioSession stuff here
        
        do {
            try session.setActive(true)
        } catch let err {
            print(err)
        }
    }
    #endif

}