DCC Archive More digital copy stuff

Discussion in 'Music Corner' started by David R. Modny, Dec 20, 2001.

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  1. David R. Modny

    David R. Modny Гордий українець-американець Thread Starter

    Location:
    Streetsboro, Ohio
    As I was scrolling through the previous thread I didn't see it mentioned so I wanted to plug, not only the checksum comparator but, the file bit comparator function in Audiograbber.

    I did some experimenting, some time ago, using two copies of commercial discs that were otherwise identical yet pressed at different pressing plants. Disc one of the Hollies "30th Anniversary Collection", one pressed in Jacksonville the other pressed at EMI's pressing plant, passed BOTH the file comparison and checksum tests when the two files were ripped to PCM using EAC. On the other hand, "All Things Must Pass" in the same scenario passed the checksum test but, unlike the two Hollies files, failed the file comparator test (don't know if this was due to a simple offset or something more substantial). Interesting to notice too that simply taking a file and putting it in something like Cool Edit and making a simple EQ change gives us the same file size but does indeed change the resulting checksum. Also, to verify EAC and my drives ripping accuracy, all of my rippped files did pass both tests when ripped several times. So, I know my drive is capable of bit perfect copies.

    What does this all add up to? Not much I suppose, but I've always been interested in the subject of pressing plants and their effect, if any, on audible sonic differences. At the very least, people here might enjoy playing with these two test functions in Audiograbber...I think it's still shareware. : )
     
  2. Sckott

    Sckott Hand Tighten Only.

    Location:
    South Plymouth, Ma
    Checksum doesn't really mean too much of anything, but can pose question for those interested enough to look into the waveform. Many times, if a label wants to darken out the blank segues or remove some unessesary 0-data at the end of songs, they've been known to do it. That as well as other VERY minor things will make CRC's look different, for sure.

    If you look at the same issue of CD, different CD manufacturer, you'll see that for the most part the CRCs are gonna match. No one wanted to screw with much once the plates were done. It's a time/laziness factor.
     
  3. David R. Modny

    David R. Modny Гордий українець-американець Thread Starter

    Location:
    Streetsboro, Ohio
    It's not so much the checksum that I'm interested in anyway. It just baffles me how the two Hollies files pass both the checksum AND bit comparison tests, while the two George Harrison files only pass the checksum. I want to know what's accounting for those bit differences in the two pressings of ATMP...while still passing the checksum. : )
     
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