I just purchased a better external microphone for casual videoing. Most sources I found said to turn the camera's microphone to OFF when using an external mic so there's no conflict. But, when I did that, no sound was recorded at all... When I turn it back on, then there's sound. So, I'm wondering what's going on, and if my external mic is actually doing the sound pick up or if it's being picked up by the camera's microphone... the sound at louder levels isn't what I was expecting from a good quality external mic... a bit crackly and distorted, despite setting the microphone to handle that. Is there something I can do to make sure the external mic is actually doing the recording?