Originally Posted by Ricci
I'm trying to figure out how to determine the dialnorm value used on individual
BR's and DVD soundtracks (DD and DTS).
DTS is usually 4db louder than DD. Both seem to have some variation from movie to movie as well. I've read the articles on what it is and the differences between DD and DTS, etc.
Dialnorm is a value entered by the person doing the encoding that is supposed to represent the level of average dialog below full scale. (Full scale = 105dB. A dialnorm value of -31 means average dialog is at 74dB.) But, there are no loudness cops around to police any of this. Some movies are mixed louder than others - both in terms of effects and dialog. And, average dialog is not measured. It's just a value entered by the person doing the encoding that may, or may not, accurately reflect the dialog level.
DD 5.1 and TrueHD encodes always have dialnorm values. dts-HD also has a mandatory metadata field for dialnorm. But, as far as I know, DTS does not. Dolby encoders default to a dialnorm value of -27. If the person doing the encoding leaves it at the default, the decoder will lower the overall volume by 4dB on playback. DTS-HD encoders use -31 as the default and if that number is not changed, then the decoder won't lower the volume. Most content producers use the encoder defaults which is why Dolby tracks usually get attenuated while DTS-HD ones do not. But, Sony now uses a -31 value on its TrueHD encodes and some dts-MA encodes have dialnorm values other than -31.
I'd like to be able to figure this out for each movie in order to set them at the same appropriate loudness level for comparison. For example the new Terminator 4 Salvation DTS is really, really loud compared to something like Pulse, or Transformers 1 with a dolby digital soundtrack which is much softer or even other DTS tracks like Horton Hears a Who! (you end up switching turning the volume up or vice a versa).
I know that some receivers or players can call this up in a sub menu. I have an Onkyo PR
-SC886P processor and also an Onkyo TX806 receiver. Does anyone know how to display this information using these 2 units or Onkyo products in general? I can get it to display when I first switch my PS3 on, but it always seems to display +4 but it does not display at any other time or when I switch sources or discs. Is there a way to recall it while a movie is playing? I've done a moderate amount of searching in the various dialnorm discussion threads that have popped up over the years, but I haven't seen any information on this for Onkyo units. It seems to be possible with some brands like Denon.
Good luck. This is a complete mess. I think some Onkyos compensate for dialnorm reductions by raising the volume back up after the decoder has lowered it. And, I believe THX certified processors lower DTS tracks by 4dB in order to match the usual Dolby offset. But, of course, if the dts-MA track has a dialnorm value other than -31, then the THX processor may end up lowering the volume too much.
The second post in this thread at blu-ray.com has a running list of dialnorm values.http://forum.blu-ray.com/showthread.php?t=121087