Audio :: Extract Sound Object To A Mono Byte Array In AS3?

I'm trying to prepend the byte array of a sound object to a captured microphone sound byte array.

It works, but the extracted sound object get pichted down and doubled in length. I guess this is because the byte array of the sound object is in stereo, while the mic byte array is in mono.

I have this:

sound.extract(myByteArray, extract);

myByteArray now contains the stereo data. How can I turn this to mono

UPDATE:

Here's a working solution:

existingByte.position = 0;
var mono : ByteArray = new ByteArray();
while(existingByte.bytesAvailable) {

[Coe]....