Well, on this forum I've heard two takes on using ALC on the DVX100/A. Some say use it, others say don't.

I noticed the following link...

http://www.bealecorner.com/dvx100/a-levels/audio-levels.html

And it suggests that the ALC doesn't affect audio levels at all until it gets into the danger range. Shouldn't that suggest that ALC is a win-win scenario? The exact quote from the above link is:

"...Below -5 dB ALC does not affect the audio response..."

I leave ALC on all of the time on my DVX100. From my tests it seems to really be a limiting compressor that only takes effect when the signal approaches 0dB. I did not use my previous camera, the PD-150's ALC, since it was an automatic gain control which attempted to adjust the gain to make everything have max volume.

It seems you give up a little bit of dynamic range (i.e., clamping begins and maxxes out at -4.5db, vs. going to 0) in exchange for (hopefully) never getting blown-out distortion.

In other words, yes, basically a win-win.

Use it.