First I must say that while this is kind of interesting to compare all this, it really is a BAD test for so many reasons.

First to be more accurate in comparing these codecs, stereo versions of Dolby, DTS, and CD at max bit rates would be more fair. That isn't possible, so it's a funky way to compare everything at best.

Next, it wasn't clear just what kind of Dolby and DTS tracks were compared. There are a lot of numbers being thrown around, but they are not set in stone. Yes DTS has a max bit rate of 1.5mb, and DD 448, (the higher one is never used). But for movies the 1.5mb rate is RARE! The rate most commonly used for DTS video is the 754K rate, not the 1.5mb. The max DTS bit rate on a movie would absolutely smoke up space like you wouldn't believe.

Next, the max for DD is 448, but the 348? rate is quite common as well.

When comparing DTS to anything it should be made clear what kind of DTS disc is being used. If it's a concert DTS title, it might run at the 700+ K rate, not the max. A DTS music CD does run at over 1.4mb and that rate is fixed.

Also, what dark side of the moon in DD 5.1 is that? I know the DSOTM 'making of' is dolby stereo only isn't that correct? So what version is this?

As for the compression techniques used, it goes far beyond simply being technically lossy. There are other tricks going on to compress the data while making the fewest changes to the sound (that can be percieved). I bet most people don't know that DD is no longer stereo past 15kHz. To save space, sounds above that become mono. Many would argue that at 15k sounds aren't as noticable. DTS has many similar tricks as well.

I tend to shy away from DTS, MP3 etc based on theory alone. The very basis of these codecs is to CHANGE the sound to make other things possible. Whether or not I or anyone else can tell is kinda beside the point. For DVD movies DD and DTS work just fine. But in the case of music we now have SACD and DVD-A, so the CD vs DTS thing is Soooo late 1990's. Sorry I couldn't resist ;0)

As for CD not being lossy, the isn't entirely true. PCM by its very nature is lossy if you really think about it. Without decimation, a CD would hold like what? 3 minutes of music?

Even having said all that, I have come across plenty of DD, DTS and CD that sound really good. But comparing them in this fashion is just plain weird. The dolby 2.0 tracks run at about 180+K? And DTS stereo doesn't really exist, except maybe as an artificial down-mix.


..... more thoughts to ponder

- Tony



www.StrangerSoundLabs.com