Microphone input not working: GetPosition hangs

I'm new and following a few tutorials on getting basic microphone input working, but....it doesn't.

Notably,
https://support.unity3d.com/hc/en-u...-to-playback-a-Microphone-input-in-real-time-
...but the code

Code (CSharp):

1. while (!(Microphone.GetPosition(null) > 0)){}

...causes the system to hang. I have the "Built-in Microphone" enabled on my Mac, and it's the first device on the list of devices, so "null" is appropriate, but GetPosition never changes state. What am I missing?

I saw a post about needing to get user permission even for standalone apps...
http://answers.unity3d.com/questions/633084/mac-built-in-microphone-not-working.html
...so I inserted the relevant code, but when I run, no dialog box appears asking for permission.

It seems from my searching around, that many people are using code by Kappine at...
http://www.kaappine.fi/tutorials/using-microphone-input-in-unity3d/
...so here is my code, copied from that with a couple other diagnostic lines added (added because the original code just hung as mentioned earlier). I have this script attached to an empty GameObject which then has an AudioSource linked to it. It compiles and "runs" but, yeah, gets stuck.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [RequireComponent(typeof(AudioSource))]
5. public class MicrophoneInput : MonoBehaviour {
6.     public float sensitivity = 100;
7.     public float loudness = 0;
8.  
9.     bool playing = false;
10.  
11.     void Start() {
12.         GetComponent<AudioSource>().clip = Microphone.Start(null, true, 10, 44100);
13.         GetComponent<AudioSource>().loop = true; // Set the AudioClip to loop
14.         GetComponent<AudioSource>().mute = true; // Mute the sound, we don't want the player to hear it
15.          while(!(Microphone.GetPosition(null)>0)){//Waituntiltherecordinghas started
16.         //also doesn't work: // while(GetComponent<AudioSource>().clip.loadState!=AudioDataLoadState.Loaded){
17.              /*if(Microphone.GetPosition(null)<=0){
18.                  print("waiting...");
19.                return;
20.                }*/
21.          }
22.         GetComponent<AudioSource>().Play(); // Play the audio source!
23.         playing = true;
24.     }
25.  
26.     void Update(){
27.         loudness = GetAveragedVolume() * sensitivity;
28.     }
29.  
30.  
31.     float GetAveragedVolume()
32.     {
33.         float[] data = new float[256];
34.         float a = 0;
35.         GetComponent<AudioSource>().GetOutputData(data,0);
36.         foreach(float s in data)
37.         {
38.             a += Mathf.Abs(s);
39.         }
40.         return a/256;
41.     }
42. }
43.  

Any help would be appreciated.

For what it's worth: The intended application is an educational utility for me and a few physics students, to make a pitch-tracking strobelight to use for demos & experiments. Unity is just of a few platforms we're considering for implementing this (e.g., Max for Live, or WebGL+WebAudio). Not going to be making any money off this, so we'd rather learn to write the code ourselves than buy some $$ asset. ;-)

Details: Unity version 5.3.3f1 Personal, Mac OS X 10.10.5.