How to Improve voice quality using "Speex"

Question

I'm working on a live video streaming project and struggling with EXTRA NOISE coming from microphone. I am using speex Codec, and here the setting which i have used.

microphone = Microphone.getEnhancedMicrophone();
microphone.codec ="speex";

microphone.enableVAD = true;
microphone.setLoopBack(false);
microphone.setUseEchoSuppression(true);
microphone.setSilenceLevel(0);
microphone.rate=44;
microphone.gain=1;
microphone.encodeQuality = 6;
microphone.

var micOption:MicrophoneEnhancedOptions = new MicrophoneEnhancedOptions();
micOption.mode = MicrophoneEnhancedMode.FULL_DUPLEX;
micOption.echoPath = 256;
micOption.autoGain = true;
micOption.nonLinearProcessing = true;


microphone.enhancedOptions = micOption;

Where should I make changes, and why ??