AudioPlaybackMode.Voice on Air for Android

Im developing an Air for Android App using Air 17 that is basically a VOIP phone. Im trying to get the Audio to come through the earpiece using the following code: SoundMixer.audioPlaybackMode = AudioPlaybackMode.VOICE; SoundMixer.useSpeakerphoneForVoice = false;

It seems to work until I start talking into the built in Mic from my android device, the audio just stops functioning all together. I tested the AudioPlaybackMode.Voice on another simple app I made where it just plays a sound file and it works perfectly.

Can anyone provide me with some insight of why this is happening or give me any advice on how to debug this issue? Thanks