What Blu-ray is best to compare DD vs HD-audio...

[DeadDog]

So I recently upgraded my system (speakers, receiver etc.) so that I can get HD-audio via LPCM from my PS3, and just better sound overall. My wife seems to think that the upgrade wasn't really worth it. We used to have an old Philips HTiB from Wal-mart and she says she can't tell a difference (although she says it's "louder" now).

I have tweaked my audio settings, calibrated the setup, set crossover's etc. I can definitely tell a difference when watching movies. Dialog is clearer, sounds are more dynamic, overall it just sounds richer. Now I know that on some level it sounds better to me because I want it to sound better . But my question to you all is, what blu-ray can I use to show my wife (or anyone for that matter) the difference that HD-audio has? I know some movies have seperate DD and either TrueHD, PCM, or DTS-HD (such as many warner movies) and others just have a core DD track within the HD track.

I am trying to find a movie where sounds/noises are present that are either not noticeable or aren't nearly as clear as they are on the HD track. Preferably a movie from my collection. I figure I can switch between the tracks either in the pop-up menu if it has it, or by changing the PS3 to Bitstream instead of Linear PCM in the options menu during playback.

So what movie, and specific scenes from it, show an obvious difference that can be irrefutable by my wife or anyone else . Any ideas would be appreciated.