Media and Listening Limitations
source dynamic range
Different recording media and transmitting techniques have widely different dynamic ranges. If the full dynamic range is used, the result is that often sounds are too loud or too quiet. Dynamic range mapping enables the soft, subtle nuances of large dynamic range media to become louder, clearer, and easier to hear. It also allows the limited dynamic range media to expand, restoring excitement to movies and television.

environment dynamic range
Room acoustics, hearing loss, and the environment have a distinct impact on the ability of a listener to hear sounds. A concert hall minimizes all external noise sources, permitting sounds with a very wide dynamic range to be heard. In a large room, the dynamic range is considerably reduced when a party is held, since the noise of the people "masks" low-level, soft sounds. Small rooms have a restricted dynamic range, requiring you to constantly adjust the volume level for loud and quiet scenes. If you have a hearing loss, this also reduces the dynamic range you can hear, preventing you from hearing soft speech sounds, which in turn makes it difficult to understand speech.