• 10-04-2004, 12:59 AM
    maxg
    I dont understand it - but I am VERY happy....
    This is long - sorry - and the most interesting stuff is at the end....

    Where to start with this one? I suppose with my Portable PC...

    My portable PC has a built in DVD burner (not a dual layer one - its not that new) which I have used to burn various home movies from my digital video camera and take a couple of backups of important data from the hard disk but not much else.

    In the meantime I downloaded an MS upgrade to the media player - to version 10. Now I dont really know what version 9 was capable of - but I started to play with 10 and have been very impressed (not that I have much to compare it to).

    Anyway I started to rip various of my CD's to my hard-disk to have some music to listen to in the office. With the on-line Cd DB this is a breeze and a typcial Cd rips in less than 5 minutes.

    Problem is that once you get into doing this it is addictive and very quickly your hard disk starts to get rather full - so I thought I would start archiving the results off onto DVD's (with 4.7 Gb a disk that fits about 35-40 albums on a single disk when ripping at 256 Kb/s).

    Now I have been told that although my DVD player plays MP3 files it probably wouldnt play back MP3 from a DVD disk - only from CD. I took this as gospel until very recently when I tried it - just for interest - and it worked perfectly!

    and when I say perfectly....

    I took a bunch of MP3 files and ripped them to DVD. I then took a small sample of the same files and ripped them to a CD (black as it happens - makes a difference?).

    Now here is the thing. On the DVD it sounds MUCH MUCH nicer than on the CD. What? Bizzare huh.

    So I am trying to find out why and I look into the setup menus on the DVD player. I should state at this point that this DVD player is one of those junky $70 units - labelled, in this case - COMET (actually apparently it should retail for a princely $130 but there was a cock up at the shop and they sold a bunch at the wrong price - my win!!)

    Anyway - the audio setup menu.

    LPCM options: Ouput 48 KHz - 16 bit or, 96 KHz 24 bit or,......192 KHz 24 bit.

    Huh? Isnt that DVDa? Apparently not in this case (I tried a DVDa sampler that came with the sound blaster audigy card that does not have a normal DVD layer and it did not work).

    So what is happening? What are these options? Is this unit upsampling the sound? If so - does LPCM imply it is only doing it for DVD sourced audio and not for PCM on a CD? Really confused.

    And it gets more bizzare....

    I brought the wife into this and asked her which she prefers - first between MP3 on the DVD and MP3 on the CD and then between MP3 on the DVD and the ORIGINAL CD.

    Guess what - she chose the DVD each time.

    Anyway I cant really explain any of this is my upsampling theory is wrong. Suffice to say - it is rather nice to have 35 to 40 albums on a single disk and be able to hop about from one to another without getting out of my chair - and without having bought a disk changer!!

    That the quality seems to have improved is mystifying.

    Anyone?
  • 10-25-2004, 10:23 AM
    Feanor
    Dunno, but by the sound of it ...
    [QUOTE=maxg]...
    LPCM options: Ouput 48 KHz - 16 bit or, 96 KHz 24 bit or,......192 KHz 24 bit.
    ...So what is happening? What are these options? Is this unit upsampling the sound? If so - does LPCM imply it is only doing it for DVD sourced audio and not for PCM on a CD? Really confused.

    And it gets more bizzare....

    I brought the wife into this ... she chose the DVD each time.
    ...[QUOTE]

    By the sound of it, your CD input is being upsampled to whichever of the LPCM options, (above), that you selected.

    Of course, upsampling can't create information that isn't on the CD. But you no doubt realized that a major contributor to sound quality is the digital => analog conversion process. With CD, your DAC is converting 16/44.1 to analog; but with the DVD playback, the DAC is converting 16/48 or whatever higher rez setting you're using.

    The long-and-short of it is that your DAC does a better job of converting the higher rez input than it does 16/44.1.

    This is somewhat like the situation with my Panasonic SA-XR25 receiver: it gives better CD sound using the analog inputs from my CD player than it does the using digital input. I've been told that the Panny samples all analog inputs at 24/192. Dunno ... but I surmise that the Panny does a PCM to PWM conversion to drive its power stage and, for this process, it likes 24/192 better than 16/44.1.
  • 10-26-2004, 06:18 AM
    maxg
    Well thanks for the feedback. I am now fairly certain that my upsampling guess was wrong - I switched to 16/48 from 24/192 and heard no difference. This leaves me completely mystified - as usual.

    Right now I am simply not questioning what is going on and accepting it. It is a real boon having my entire Cd collection on 7 disks!!! to have that convenience alongside a quality I can live with to say the least is a win and a half.

    Interestingly we have now played with 8 DVD players and only one other would read the disks I created. The other player sounds like crap with these disks - but then again it doesnt sound great with anything - hard to tell if it sounds better with these than normal CD - but ultimately it doesnt matter much.