iTunes Audio compared to Vudu

[twobelowpar]

So I'm no techie, but I've been noticing this for a while now and it's always bugged me. When it comes to picture quality, I find iTunes and Vudu to be virtually the same to the naked eye. Sometimes iTunes may seem smoother but I could be wrong. Now audio is a completely different story. With my modest home theatre system, I have to usually have the volume up to 40 or more to have an iTunes movie at a comfortable listening level through ATV3. With the same hookup, my Vudu movies through Roku 3 are just as loud or even louder with the volume set around 20. At first I thought it was because of Roku, but now that Vudu has AirPlay support, I tried an HDX film that way and it was the same thing. Volume did not need to be set nearly as high as iTunes. It's always louder and crisper with Vudu than iTunes. I prefer my digital collection to be built through iTunes because of the menus and extras (and ATV), but this audio issue really is a nuisance.
Thoughts?

 

[zhenya]

Is the Roku/Vudu compressing the dynamic range? That would account for this kind of difference.

 

[twobelowpar]

I have no idea. My knowledge of such things is pretty limited.

 

[zhenya]

The AppleTV has a setting for this you could play with. http://www.cultofmac.com/396048/pro-tip-get-your-apple-tv-sounding-just-right/

See if changing it to Reduce Loud Sounds makes it more to your liking. What this does is equalize the volume of all passages. Many movies, mastered for playback in a theater at very loud volumes, have a wide dynamic range from the softest whisper to the loudest explosion. Sometimes this doesn't translate well at home.

Or maybe I'm leading you down the wrong path, but it's what I can think of!

 

[priitv8]

It is strange to judge sound quality by it's loudness, but the first thing that comes to mind - have you checked, if both are playing back a stereo or surround sound?
Have you tried to switch iTunes movie from surround to stereo? Does it make any difference?
In my own experience, on aTV the stereo soundtrack is always louder than the surround soundtrack. As I understand, this is part of the AC3 standard specification.
https://en.wikipedia.org/wiki/Dialnorm