Originally Posted by Possumgirl
I have several BRs that have both DTS-HD-MA and DD5.1 tracks. Oddly they usually default to the Dolby track until I change it. I don't think it's my imagination that the DTS track sounds better: clearer, sharper, cleaner for lack of a better term. Another thing I notice is that DTS generally plays louder so I don't need the same volume level as with Dolby. Perhaps DTS is always mixed differently?
DD5.1 has a lot of metadata that a properly licensed decoder has to respect. For example, the decoder will check the dialnorm value to first attenuate the volume to -31 dB correctly, whereafter it will apply any DRC (dynamic range compression) on the track as well. The result is that DD5.1 often is lower in volume, and more dull sounding, than a DTS track.
Usually one can simply disable DRC on the receiver, and raise the volume, to make it sound very close to the DTS track.