What's wrong with TrueHD?!?

[DaViD Boulet]

What's wrong with the Dolby TrueHD on SpiderMan 3 Blu-ray???

In my review at dvdfile.com, I notice a definite compromise with the sound of the TrueHD compared to the PCM on Spiderman 3.

http://www.dvdfile.com/index.php?opt...=6337&Itemid=3

But I did discover something that concerns me greatly that the studios need to address and correct NOW early in life of TrueHD software: when I compared the PCM uncompressed 5.1 track to the Dolby TrueHD track on the third disc (which contains both types of lossless audio), despite the theory that the two audio tracks should sound identical, the PCM track was audibly superior to the TrueHD and I didn’t have to struggle to hear the difference… it was obvious. The PCM track was more robust, textured, realistic, and also seemed louder (I level-compensated when comparing to make sure I wasn’t being biased by mere level differences). As good as it was, by comparison the Dolby TrueHD track sounded slightly restrained, and “smoothed over”. My suspicion (even though Sony as stated they do not set the dialog normalization flag to engage processing) is that this slightly compromised fidelity of the Dolby TrueHD track is a result of dialogue normalization processing which is applied after the lossless sound file is extracted in the playback hardware’s decoding engine, and effectively re-writes every bit word with a new value as the amplitude of the entire digital waveform is digitally recalculated/reduced. I should point out that my audio gear, while better than the average Circuit-City rack-system, isn’t comprised of out-of-reach esoteric gear; I’m confident that most critical listeners with “good” sound systems will be able to hear the difference between the Dolby TrueHD and PCM soundtrack on the third film without difficulty. Sony and other studios: PLEASE learn how to properly optimize Dolby TrueHD so that it sounds 100% identical to the PCM original.

Greg from thedigitalbits notices the same thing:
http://www.thedigitalbits.com/review...eviews009.html

The audio is no less disappointing. Encoded with both Dolby TrueHD and linear PCM tracks, Spider-Man 3 on Blu-ray is a breathtaking aural experience. The entire soundstage is used to full effect with clear dialog, pounding low frequencies and split-surround effects. Between the two high-end soundtracks, the linear PCM track is the preferred choice. Differences are slight, but there are differences nonetheless. The Dolby version has a slightly more plugged-up sound when compared with the airier, more transparent PCM track. This is likely due to the lower, variable bit-rate of the Dolby technology compared with the higher, fixed bit-rate of PCM. Again, these are not differences that slap you in face, but they're enough to notice.

Ok, so what's going on? Paidgeek, I'm almost 100% convinced that Dialogue Normalization *has* been applied to these TrueHD tracks. When your audio engineers told you that they wouldn't do it, were they aware that the equipment does it by default and that if they didn't want DN applied they'd have to manually reset the flag to -31?

I'm sure that the same problem exists with the TrueHD tracks on the other discs, but without the PCM to compare the compromise isn't as apparent (true for probably every TrueHD encoding out there on either format).

Help us. What's wrong? DolbyTrueHD won't be "lossless" until it's 100% transparent to the PCM original. Nothing less will do.