That's something I've been wondering for some time,why is Dialogue Normalization used on home multichannel mixes on movies either on DTS-HD Master Audio or Dolby TrueHD/Atmos? Not only that, it changes on different movies and codecs. I've noticed that most DTS-HD Master Audio tracks use to have a value of +4 dB of Dialogue Normalization, and that changes on Dolby TrueHD/Atmos tracks that ranges from +1 dB to +4 dB. I don't understand why Dialogue Normalization is used and why seems to be necessary as the mixing engineer of the film adjusts all different levels of sound FX and dialogue on the final mix, yet most if not all home multichannel mixes use Dialogue Normalization. Even DTS on the instructions of its 2009 DTS HD Encoder Suit advices not to use attenuation and leave the level at -31 dBFS that leads to Dialogue Normalization being unused. Any idea about this subject? Thanks in advance for your replies.