Audio questions

Since posting my ''cheap audio solution'' video on my main channel I have been getting a lot of questions on how it works, what cameras it works with, that it doesn't work etc. So I thought I'd answer some questions here on my blog. First off I'm by no means an audio expert but here is how I understand it, the preamp in your camera is the audio interface that tells your camera how sensitive it should be to sound, so the higher you put the gain the more sensitive the preamp will be and you'll get louder audio. But because the preamps in the canon cameras are very poor, even setting the gain to pick up normal audio levels you get a lot of hiss and background noise. So the way I see it is the more sensitive you make your preamp to sound the more noise and hiss you get, so the solution is to turn the gain level on your preamp extremely low and this gets rid of the noise, but the only problem is you won't hear any sound using the on camera mic with the preamp's sensitivity set so low. So the way we beat that is boosting the levels of an external mic before it goes into the camera, so we still get a good audio signal even with the gain set extremely low. Thats what I did with the fiio E3, I simply boosted the levels of my mic before it went into my camera so I wouldn't have to use the preamp in my camera to get the correct signals. This idea can work with a lot of different gear and different cameras but its important to know why you'd do something like what I did and why it works.