應用調幅粉紅噪聲操作

Question

AudioKit提供與淘洗，創建白噪聲文件如下：

let generator = AKOperationGenerator { _ in 
    let white = AKOperation.whiteNoise() 
    let pink = AKOperation.pinkNoise() 

    let lfo = AKOperation.sineWave(frequency: 0.3) 
    let balance = lfo.scale(minimum: 0, maximum: 1) 
    let noise = mixer(white, pink, balance: balance) 
    return noise.pan(lfo) 
} 

然而而非平移，我期待改變以下參數的幅度（從SoundForge臨）：

// AmplitudeModulation -> Sine 
    // 0.15 (s) -> Modulation frequency 
    // Minimum amplitude: Up to -30.0 
    // Stereo pan: Up to 20 
    // Dry out -30db 

這可能使用AudioKit嗎？

Answer 1

您可以使用AKTremolo。

class ViewController: UIViewController { 

    let whiteNoise = AKWhiteNoise() 
    let tremolo = AKTremolo() 
    let mixer = AKMixer() 

    override func viewDidLoad() { 

     AudioKit.output = mixer 
     AudioKit.start() 

     whiteNoise >>> tremolo >>> mixer 
     tremolo.frequency = 0 
     whiteNoise.start() 

     let slider = AKSlider(property: "Tremolo") { value in 
      self.tremolo.frequency = 100 * value 
     } 
     slider.frame = CGRect(x: 0, y: 100, width: view.bounds.width, height: 100) 
     view.addSubview(slider) 
    } 
} 

Answer 2

您可以使用AKOperationEffect進行幅度調製。例如：

let Amplfo = AKOperation.sineWave(frequency: freq, amplitude: 1.0) 
let Output = AKOperationEffect(generator) { generator, _ in 
       let lfo = max(Amplfo,0) 
       return generator * lfo }