Ripit Volume Loss

Has anyone else noticed a volume loss in terms of ripping to hd then converting the master rip to a mp4. I've noticed that the mp4 isn't as loud as the master. Anyone else?

what are your settings for handbrake? I'm stuck between mkv and mp4, do you ever change the audio bitrate or just leave it at 160?

I had to crank the gain to 10 just to get the same output level on the as the master.