var engine = AVAudioEngine()
var environmentMixer = AVAudioEnvironmentNode()

func initSound() {
    let player = AVAudioPlayerNode()
    let url = NSBundle.mainBundle().URLForResource("sound", withExtension: "wav")!
    let f = try! AVAudioFile(forReading: url)
    engine.attachNode(environmentMixer)
    let format =  AVAudioFormat(standardFormatWithSampleRate: engine.outputNode.outputFormatForBus(0).sampleRate, channels: 2)
    engine.connect(environmentMixer, to: engine.outputNode, format: format)

    engine.attachNode(player)
    engine.connect(player, to: environmentMixer, format: f.processingFormat)

    environmentMixer.renderingAlgorithm = AVAudio3DMixingRenderingAlgorithmHRTF

    player.scheduleFile(f, atTime: nil, completionHandler: {print("done")})

    player.position = AVAudio3DPoint (x: 0.5, y: 0.25, z: 0)

    engine.prepare()
    do {
        try engine.start()
        player.play()
    } catch {}
}