DVD-Audio Flag Noise/dropouts

Discussion in 'Archived Threads 2001-2004' started by David Miller, Apr 14, 2002.

  1. David Miller

    David Miller Auditioning

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    David Ranada wrote in his Sound & Video Magazine column about the problem of noises followed by dropouts between tracks on some DVD-Audio discs and I ran into the same problem with one of the first four discs I bought. He postulates that it may be due to the software flags that are inserted between tracks. I wrote an e-maill message to David recounting my experience. In case they don't publish it, I'm reproducing the full text of my message below. Anyone else having the same problem? Maybe we ought to start a list of titles that exhibit the problem.

    "A few weeks before I read David Ranada's Tech Talk article in the May 2002 issue, I bought my first four DVD-Audio discs. One was Strauss's 'An Alpine Symphony' (EMI Classics 7243 4 92396 9 2) and, when I first played it on my Toshiba SD-4700 DVD Video/Audio player, I was astounded to hear the very obvious noise/dropout artifacts between tracks that he and Ken Richardson observed. I had no idea what was going on until I read the article. I suppose we don't know much more now, as David reports that it is still an on-going investigation, but at least I do know that I'm not alone in having that problem. These artifacts are especially disturbing in 'An Alpine Symphony', because the piece is a tone poem, with no breaks as there usually are between movements or songs. The music is suddenly interrupted, you hear a soft pop, and then there is a dropout that seems to erase the next moment of music. 'An Alpine Symphony' is very programmatic and there are twenty-two sections, varying from 0.47 to 6.05 minutes long, that should seamlessly flow together to make up a 49.9 minute long composition. It is a highly emotional piece and the mood is completely destroyed by these noisome interruptions every few minutes. I can't imagine how EMI, a very reputable and technically advanced company, ever released such a thing. Surely they played it back on a consumer grade player before shipping out thousands of units. Oh well, at least I can enjoy the Dolby Digital version of 'An Alpine Symphony' on the same disc. It doesn't suffer from the same artifacts.

    Trying to isolate the problem logically, I find that I am stymied. None of the other three discs that I bought suffer from the problem, even though one disc was also an EMI production (Wagner Preludes, EMI Classics 7243 4 92397 9 1). Both EMI discs are 2001 digital remasters of analog tape recordings made in the seventies. The Wagner disc has flags only at the conventional breaks, but the pops should have been audible, if they were there. The other two discs were both original multi-channel digital recordings and were pristine.

    It appears that the two discs digitally remastered from analog masters are done at a lower sampling rate than the ideal 96 KHz, but, considering that the 48 KHz they used allows more than enough frequency response to get everything that is on analog tapes, I suppose that is a reasonable trade-off. The price for those two discs is considerably less than most digitally recorded discs, too."
     
  2. Duke H

    Duke H Stunt Coordinator

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    First, the DVD-A thing...I love DVD-Audio, and I too have an SD-4700. The only difference between that and the "Flagship" Cinema series model is that the C-series model plays HDCDs. Who cares? Anyway, I only have a few DVD-Audio disks, but they work fine...Hootie & the Blowfish "Cracked Rear View," and the Doors "LA Woman." Most of my other disks of this persuasion are DTS and DTS-ES disks. Maybe the problem stems from the MLP format...what if some parts of the signal have a tough time registering with the player? I don't know...just an unthoughtout theory. All I know is that DVD-Audio so far seems to be kicking SACDs butt, in my opinion...similar sound quality between the two (when listened to on entry level players). SACD has the titles, but DVD-Audio has (a) the videos and menu screens, and (b) Toshiba's backing.

    Anyway, on to the receiver. Personally, I don't really care that much for Onkyo. My friend had one, and it clicked and froze up for 20 seconds or so when switching between DD and DTS. Not trying to rag on your gear...just adding a preface to my answer.

    Does your receiver down-convert to 6.1 (forgive my ignorance, but I didn't pull up the specs on it before I started posting). If it does, problem solved...just use you 6.1 set up. The reason I ask is because a lot of 6.1 receivers will down-convert to 5.1. If not, I'm kinda' short on ideas...If you dummy out the load from that 7th channel, your receiver will send only 1/2 of the rear tracks to your 6th speaker. A round-about way would involve sending both signals into a studio-grade direct box, and then sending the line-level output into a second amp, which would then go to the speaker. There's gotta' be an easier way, but it's like 2:30, and I've been us since around 9 AM...Drifting off into unconsciousness...
     
  3. John Kotches

    John Kotches Cinematographer

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    David,

    How many different DVD-A players have these discs been tried on?

    All titles are EMI that fail? This would point to an authoring issue with EMIs discs. Given that they have some serious ergonomic / user interface issues, I wouldn't be at all surprised if they have some unusual error in the titles you've purchased.

    I think Duke is grasping for straws, as MLP would be problematic across more discs than these 3 by now.

    Regards,
     
  4. Dan Hitchman

    Dan Hitchman Cinematographer

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    I would think the problem stems from having each individual track addressed as a separate file. Some circuitry would have dropouts when aquiring and reaquiring the data stream.

    This happens to me just listening to the DD or DTS tracks on DVD-Audio discs as these tracks are separated too. It takes a second for the relays to pop back on. If you do happen to have processors or a DVD-Audio player with slow or noisy relays then this can be very annoying.

    When the DVD-Audio specs. were being created they should have made the tracks more like on a PCM CD: The stream doesn't cut out if you don't run the player in random/shuffle mode because the tracks are run back to back to back with no blank signal spaces in the PCM data stream.

    Dan
     
  5. John Kotches

    John Kotches Cinematographer

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    Dan,

    You would think that is the case, but the data is in a stream, limited to 1GB in size, it has no relation to the tracks.

    Regards,
     

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