There are three different factors here.
1) Not all sources will have same sound level even digital sources. Some receivers have an internal trim per source to adjust
2) Many TV sources are flat, dynamically speaking; So you turn up the volume to hear dialog, and it gets louder, but still not dynamic; you forget you turned it up for TV dialog, and put in modern action movie and it's super loud...happens to me too. One option is to reduce the dynamic range of the volume. See your receiver manual for options.
3) Some movies will have lots of bass. Modern action movies. Tron, for example (the recent one,) has crazy amounts of bass. You can reduce dynamic range which can help if you don't like this. If that does not help enough, manually adjust bass using subwoofer's controls or receiver remote control (see your receiver manual.) Make note of normal setting, so you can restore the setting as needed