OK, to answer David's last question on how the test I did was done, I used a 24 bit master. There were no additional processes introduced in the chain when the transfers were made. The Dolby 562 was in a mode that bypasses all dial norm, compression and downmixing parameters (this mode is representative of the original master used). A data rate of 448 was used for the ac-3. The DTS was encoded through the CAE-4 hardware encoder at a rate of 754 and decoded as I stated previously.
The results were very interesting. I depended on who was listening, what program material was used (both music and film soundtracks were used), at what amplitude etc. Let me say first that both codecs work very well and each company should be proud of their process. In short the differences between DD and DTS were minimal. Both sounded great but each had slightly different anomallies in playback. Some people heard a slight difference others heard no difference at all. They both gave a very good representation of the master.
My conclusion was that the codecs being this close shows me that if you are hearing a vast difference between DD and DTS on your systems at home that there is some processing going on that you are un aware of. It may be user adjustable or something that the manufacturer has introduced without your knowledge. But the actual codecs are close enough that you must have exceptional hearing with a system that is better than that in most studios to hear any noticeable difference. This was an A/B(C) test. 'C' being the original master and we still had difficulty telling a difference between tham. Those of us who heard the difference (almost all of us) had difficulty describing what that difference was.
On another note: it was interesting seeing the reaction of some of the audio professionals when the women who work in the office could tell the difference as well as they could. I say this because women have better hearing than men on average and the differences were very slight. They would even describe the difference in a similar manner.
So if you hear a significant difference on a disc that used the same master, your system itself could be the difference.
That is just my findings and opinion. Your milage may vary.
Have a nice day,
Roogs