Onkyo TX-DS797 and Dolby EX



I’ve searched the forums and have not found a thread relating to the information I am seeking. Here is my dilemma: I am in the dark ages with respect to surround decoding, using an old Pioneer VSX-D1S pro-logic receiver (in perfect condition and very hard to part with!). I am finally going to buy an new receiver mainly to upgrade to digital surround formats. I am looking into the Onkyo TX-DS797. Sounds great on paper and has composite to S-video conversion so I still easily use some of my older components (e.g. vintage laserdisc player and about 120 discs).

I am however hearing a lot about this problem with decoding some Dolby Digital EX movies (e.g., Jurassic Park, Pearl Harbor). The sound apparently drops out badly. Onkyo acknowledges this problem but says it is due to the use of “flags” in the encoding for these movies and suggests just watching the movies in pro-logic or DTS (if the movie is encoded with DTS, and of course not all are). I wanted to get to the bottom of this and contacted Dolby Labs directly. I was directed to a very knowledgeable person who explained the problem quite clearly. It does have to do with the use of some new software features in the EX encoding and incompatibilities with surround processing chips used by some manufacturers. The Dolby rep told me they caught this early and informed DVD makers to stop using the new features until they could work out the software/hardware incompatibility. He said the problem only occurs on 4 DVD’s (JP, PH, Atlantis and one other I can’t remember). It sounded like not a huge deal to me. I only own JP and it has a DTS soundtrack that is not affected. It did not sound like the problem would continue with future DVD releases.

My concern is this: I just read another on-line review of this receiver and the reviewer said that not only did the sound drop out on the mentioned DVDs, but also on nearly ALL movies on HBO, through the cable tv system. Does anyone out there have any experience with this receiver or others to know how widespread the problem is? Onkyo and Dolby both said it also affects other brands including Dennon and Harmon Kardon (I believe). Also, has anyone had a bad experience decoding other DVDs besides the ones mentioned? I’m trying to understand if this is going to blossom into a huge problem as new movies are put out in DD EX. The last thing I want to do is to “upgrade” to Dolby Digital and EX, then have to watch movies in pro-logic mode anyway! I can do that now without spending a dime!


I might be wrong on this one but it was my understanding that all the problem was was that the amp wouldnt detect the flags on the discs and so wouldnt change to EX automatically,meaning you would have to select EX manually instead.


Whoops,just read an article in HCC that describes the problems your are having,although it doesnt mention your product specifically if Onkyo are being honest enough to admit the problem I would take it as truth.
It is also says that Dolby claims only a handle full of discs have been released using the new bitstream flags and the company has urged all authoring houses to discontinue using them.


Active Member
I'm curently using the 797 on loan from Sevenoaks. I have played a few 'ex' DVD's and the sound hasn't dropped once.

Good amp though, very good sepearation of channels, ProLogic II and a few of it's DSP's work very well and the thing is built like a tank. On the negative side 2 channel stereo is OK not fantastic and the remote is not the best.

If you need anymore info let me know

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