Strange Echo when recording and instantly playing sound from mobile device

I'm working on a mobile app, in which I need to input and repeat microphone input almost immediately..

I've worked it out and it works great when I play it from within the Unity Editor. I get some very strange behavior though when I try it from my Android phone (Galaxy Note 3)..

So I decided to run some tests and noticed quite different behavior..

Using this sample code:

 using UnityEngine;
 using System.Collections;
 
 public class testingMicScript : MonoBehaviour {
 
     void Start () {
         audio.loop = true;
         audio.clip = Microphone.Start (null,true,10,44100);
         while(!(Microphone.GetPosition(null)>0)){}
         audio.Play ();
     }
 }
 

and playing it from withing the Editor it works great, I speak and hear myself back after a few milliseconds. I compile the app and run it from my phone and when I speak I get a very strange echo which goes on until the sound is completely distorted and I get a strange hiss..

Why is that? Is there any particular setting I should go through? Or do I have to change something in my code..