xxxIndyxxx: I actually think this solved it!! Thank you so much! Now my youtube videos have improved on a technical level. I myself am still not so good though but I hope i'll get better :D
Glad I was able to help. Automatic gain can be useful in some situations but what it basically does is monitor the input level and if it is low, it increases the gain (amplification) essentially listening for further away sounds. The idea is that if you walk away from a microphone for example, the AGC will increase amplification to keep your voice at the same volume. In the right scenarios it works well.
Problem is, if you stop talking loud enough, it increases amplification trying to pick up further sounds and then when you speak it gets a loud BOOM having over-amplified your voice, which it then detects and lowers the gain quickly - but you still get the brief sudden BLAST of unwanted loudness. On the other hand such a feature works great usually on say... a telephone on speakerphone while you're walking around the room doing stuff. Not so great for making videos though or at relatively fixed distance from a mic. :)
Another problem AGC causes, is that because it blasts the gain in search of a signal, it greatly amplies all background noise/hum, fans etc. then once you speak it backs off and silences them. Personally it drives me nuts. :)
If you're making Youtube videos you might want to consider going over your camera's video settings also as the automatic gain, automatic white-level, autofocus and other auto stuff like Logitech's "Realsound" etc. all have similar effects on video and audio. I find all the auto-white balance/gain on video to be very atrocious and it causes the video to randomly get dark/light and jump all over the place simply by slightly moving my face or blinking an eye even at times. :) I disabled all that auto stuff, twiddled with each setting, watched some tutorials on how to set the controls on the camera manually and then set it up with all manual control. You have to adjust gain/exposure/white balance, brightness and contrast manually to get it working well at first, and then any time the actual room light levels change at all, but a few presets for common lighting setups, or using a standard lighting setup solves that problem easily enough. :)
Also, I found for example on the Logitech C920 and probably other cameras also that autofocus really is only useful if the camera is between 1 inch to 18 inches away from the subject being focused. Since I am almost always 18" or greater - autofocus is useless as it doesn't focus beyond that point - however it will sure try to if enabled which causes the image to randomly blur as movement happens not unlike AGC with audio.
Anyhow, hopefully these tips help you or others who might read them out a bit with video as well. I'm no expert at it but I've picked up some useful tidbits here and there along the way myself that have been handy. :)
