Lossless, be it TrueHD, DTS-HDMA, or PCM, can be slightly better than some DD/DTS tracks but not all. At approximately 5.5:1 compression ratio, studies have shown that lossy audio in general becomes audibly transparent to lossless audio; while there are different codecs that slightly vary in efficiency, this rule seems to hold true across most. So PCM/TrueHD/DTS-HDMA might sound better than 448kbps DD5.1, but the difference is minimal to nonexistant compared to 1.5mbps DTS. Also, in terms of bitdepth and sampling rate, generally 16bit/44.1khz is the threshold where people can tell a difference.
Now, if you think you hear a difference when you shouldn't, there could be a number of factors that come into play. First is master quality, which tends to be more important than compression rate. Check out Top Gun on Blu-ray for instance - the DTS-HDMA track sounds a lot more aggressive than the TrueHD/DD tracks. In fact, most would probably agree that the lossy DTS core of the lossless DTS-HDMA track of Top Gun sounds better than the TrueHD track. Go check it out for yourself. This holds true for music as well; often CDs will be mastered with lots of distortion (see the loudness wars
) while "high resolution" discs will have masters that are not compromised. Master quality generally makes a much larger difference than lossy vs lossless or "high resolution" vs. 16bit/44.1khz.
The second thing that comes into play is placebo effect. Our brain can trick us into thinking something sounds better or worse when we think it is supposed to. Placebo effect is a VERY powerful thing, and it is amazing that the huge difference we heard can often go down the drain when we are asked to identify the huge difference we heard without knowing which track is which.
So in conclusion, if you have high bitrate lossy then no, PCM shouln't sound miles better. And yes, it is possible for PCM to sound worse
than lossy DD/DTS due to different masters being used; again, use Top Gun Blu-ray DTS lossy core vs. Top Gun TrueHD lossless as an example. In the case of your movie Hellboy, it is very possible the DD track used a better master. Unbreakable is another example of this, the PCM track has lots of popping/distortion in it while the DD track does not.
Oh, and here is some science to back up my statements as another poster requested:http://www.aes.org/e-lib/browse.cfm?elib=14195http://www.heise.de/ct/00/06/092/
(translation of heise.de article): http://www.geocities.com/altbinaries...l/mp3test.html