Dynamic Range setting - I don't get it

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Joined: 12 Aug 2007
Dynamic Range setting - I don't get it

I have often wondered about the different settings in PowerDVD (and other software players) for the Dolby Digital Dynamic Range.  The names chosen for the settings, I don't quite get.

"Quiet Environment" - Experience the full dynamic range of Dolby Digital

"Normal Environment" - Experience the compressed dynamic range of Dolby Digital

So if it's quiet and I could hear everything any way, the sound is full.  But it's "normal" then the sound's going to get compressed?  Does that make sense to any one?  The only thing I can explain to myself is that maybe it means that if it's quiet, then the whispers are whispers and the booms are booms, and if it's "normal" with a little noise going on then the sound is more "normalized".  But then this doesn't really make sense to me either because if the sound is compressed how could the whispers be boosted?

Joined: 30 Sep 2006

Yes it's terribly labled.

"Normal" means the dynmaic range is leveled out, so the high and lows are evened out more. So yes whispers would be perceived as louder then before relative to the sound of the booms, i.e. the crazy spikes in the differences are smothed out.

In theory you want it set to Quiet, so it doesn't try and mess with the dynamic range.

Also note that in S/PDIF mode this wouldn't be active at all, the equivallent settings for this are on your receiver. It's often called "midnight mode" or "dynamic range." And this only applies to Dolby sound tracks, DTS has no such metadata, DTS doesn't believe in allowing the alteration of their soundtracks.

Joined: 2 Oct 2006

htpc_user wrote:

But then this doesn't really make sense to me either because if the sound is compressed how could the whispers be boosted?

You need to think of it in terms of volume.  And the "full dynamic range" as the difference between the quietest and loudest portions of the audio track.  The "compression" they're talking about is probably raising the volume of the softest or most quiet portions of the audio track.

Dude...  How old IS this FusionHDTV3 ???

Joined: 30 Sep 2006

That's what I was trying to say. The perceived difference in volume is adjusted inward so the highs and lows are less high and less low.

skirge01's picture
Joined: 21 Dec 2006

Maybe I'm completely off base here, but this is my uneducated opinion:

Compression in this sense may be a removal of something, but it's not quality (or, it shouldn't be).  In a quiet environment, humans can typically hear frequencies between 20Hz and 20kHz (depending on your age, but that's a different discussion).  So, via the "quiet" DD setting, you hear that entire range of frequencies.  However, when you factor in the ambient noise for a "normal" environment, you're not going to be able to hear all of those frequencies over the ambient frequencies.  Thus, the compressed audio may be the removal or adjustment of certain frequencies to other volumes or frequencies so that you can hear them over those ambient ones.  I'd bet there's some pretty intense math algorithms involved in determining what's "adjusted", since it's not able to know what kind of ambient noise is around, but this explanation does seem to make sense...  at least, to me!  ;D

Joined: 3 Oct 2006

No, Matt's right.  It doesn't have anything to do with equalization of frequencies, which would be equivalent to the "Loudness" feature in many car stereos.  This particular function "compresses" the range between max volume and minimum volume.  Many receivers call this a "night mode", because it allows you to listen to quiet dialog at a reasonable level without having your ears blown out the next second when something explodes.  It's the same thing as those devices that keep loud commercials from being so loud (it's also in some TVs).

I never understood the labeling the OP is mentioning between Quiet Room and Normal, until I got married and realized that when there's a woman in the house, you never have a "Quiet Room"!  Wink

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