If you want the best picture from your HD100. Stop using "Full Auto".

Flip open your LCD and you will see 2 switches for manual/auto audio modes.

I always use AUTO mode for audio because like you said, it has clip protection, but I use manual controls for everything else.

The problem with the auto white balance is that it loses it's setting if you turn the camera off/on, and takes 30 seconds to re-white balance, not to mention, it's not as accurate.

Also, Full Auto forces you to use 0-18db gain and it disables the manual iris switch.

Personally, I would not put audio on auto mode because you get odd effects as the circuit tries to to adjust to the right levels. You do not get optimal sound this way.

Rob

Second Robert's comment. My personal preference if using a single audio source is where possible to run the audio into two separate channels, set the levels manually with one at optimum, the other lower to avoid clipping.