My DCR-PC100 has no manual gain control. When I plug an external zoom microphone in, there's a lot of background noise (presumably, because of the built-in automatic gain control) while the room is silent. As soon as there's audio to be recorded, the noise is gone. The microphone has 2 settings, and the background noise is worse at higher sensitivity.

If my assumption is correct, is there a way to defeat the automatic gain control? TIA.

P.S. Since this is my 1st post, sorry for jumping in with questions. I just wanted to say that I've discovered this board a couple of days ago, and I'm absolutely extatic about the material I've read so far! Thanks!

Unfortunately, I don't know that camera, but didn't want your post to go unanswered. Some cam's can't have the AGC turned off, it's not a feature on all DV products...Darn.
You might want to check the owners manual or see if there is anything labeled 'Gain' in your menu?

I don't think you can control audio levels on that camera at all. It was the immediate predecessor of my DCR-PC110 and it doesn't either.

Thank you both for your replies. Indeed, the camera has no controls to adjust gain. I was hoping that you may've come across a solution for cameras without manual gain, like some sort of a gadget plugged in between the camera and microphone. Since I'm no electronics expert, this is probably just wishful thinking on my part... The only suggestion I've received so far from another forum was to precede my recording with some hand-clapping. Applause BEFORE performance? ;)

Thanks again!