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Conference napalm::commusic_v1

Title:* * Computer Music, MIDI, and Related Topics * *
Notice:Conference has been write-locked. Use new version.
Moderator:DYPSS1::SCHAFER
Created:Thu Feb 20 1986
Last Modified:Mon Aug 29 1994
Last Successful Update:Fri Jun 06 1997
Number of topics:2852
Total number of notes:33157

2622.0. "CD Labelling : "DDD" ??" by SWAM2::MOELLER_KA (Up your old quota) Fri Apr 26 1991 17:27

    Query :  just suppose someone was preparing to cut a DAT master for CD;
    suppose the original stereo tracks were recorded MIDI direct to PCM
    video.  In a pro studio, PCM gets transferred to DAT, with possibly
    some final ANALOG EQing done on the way to the DAT.  Could the final CD be
    ethically labelled "DDD" ?
    
    thanks ! karl
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2622.1KOBAL::DICKSONI watched it all on my radioFri Apr 26 1991 18:2317
    The orginal signal was not "MIDI direct to PCM".  The MIDI controlled
    something that output (gasp) analog voltages that were converted to
    digital by the PCM recorder.
    
    That small amount of analog, which was never recorded, does not appear
    to violate what DDD means, so my guess is that the EQing would not
    either.  Of course, the EQ equipment could be incredibly noisy, so
    the affect would be just as bad.  But my understanding that the three
    letters in DDD refer to how the various stages are *recorded*, not
    how they were created or processed.
    
    Probably the audiophiles will want to create a new notation, so they
    can identify a pure-digital process, conveniently forgetting that a
    digital process can introduce noise just like an analog one.
    
    "Sure, this CD is all digital.  Nothing analog after it hit the
    microphone.  Sample rate?  Oh, about 20K per second, 8 bits.  Why?"
2622.2SWAM2::MOELLER_KAUp your old quotaFri Apr 26 1991 20:537
      <<< Note 2622.1 by KOBAL::DICKSON "I watched it all on my radio" >>>

    >The orginal signal was not "MIDI direct to PCM".  
    
    YOU knew what I meant - it didn't hit analog tape.
    
    karl
2622.3FWIW, though nobody can hear the differenceRICKS::SHERMANECADSR::SHERMAN 225-5487, 223-3326Sat Apr 27 1991 02:5213
    When the PCM goes to DAT it is apparently being converted to analog.  So, 
    the fact that you do a little analog EQ makes little difference, IMHO.  
    The issue has to do with whether or not the signal gets converted to 
    analog along the way.  If it does, then a "DDD" label would be
    misleading.  This means that, technically, if conversion of a 48 kHz
    sampled signal is converted to 41 kHz via analog conversion then you have
    "cheated", even though it is all digital equipment.  The noise added
    would come from the conversion.  My understanding is that in order not
    to introduce noise and in order to avoid cheating, you need to sample
    at CD sample rates and keep it in the digital domain from the sound
    generation to the CD.
    
    Steve
2622.4I Think You're DDDDRUMS::FEHSKENSlen, EMA, LKG2-2/W10, DTN 226-7556Mon Apr 29 1991 12:1613
    My understanding is that same as .1's - the three letter code references
    the recording format (respectively the master medium, the mixdown
    medium, and the commercially offered medium).  Since there aren't a
    whole lot of studios around yet capable of doing signal processing
    *entirely* in the digital domain, it's a good bet that the mixdown of a 
    lot of DDD recordings involves spending some time in the analog domain.
    
    The "all digital" recording chain, with A/D and D/A conversion only at
    the transducer extremes of the chain (i.e., the microphone and
    speaker), isn't here yet.
    
    len.
    
2622.5DCSVAX::COTEThe keys to her Ferrari...Mon Apr 29 1991 12:3511
    Don't the 3 Ds stand for ...
    
                          DDD
                          |||
                          |||____Master
                          ||___Mixed
                          |__Recorded
    
    ...?
    
    Edd
2622.6Yes, but...DRUMS::FEHSKENSlen, EMA, LKG2-2/W10, DTN 226-7556Tue Apr 30 1991 15:034
    re .5 - see .1 and .4; but I think you've got the order backward.
    
    len.
    
2622.7SALSA::MOELLERTue Apr 30 1991 16:347
    Thanks for the input - "DDD" it is !
    
    karl
    
    p.s. Had a nice visit from Chad Leigh on Sunday.  He was down to Phonyx
    for a family wedding, and drove to Tucson for a studio visit and some
    good Mexi food.  
2622.8I've got some AAA LPs...WEFXEM::COTEThe keys to her Ferrari...Tue Apr 30 1991 17:586
    .4 makes mention of the "commercial offered medium" as being one (3rd)
    of the "D"s. My understanding of the label doesn't square with that.
    (I could be wrong!) Mattery fact, I suspect it would be entirely
    possible to offer a DDD vinyl LP.
    
    Edd
2622.9Digital Vinyl, Indeed...DRUMS::FEHSKENSlen, EMA, LKG2-2/W10, DTN 226-7556Tue Apr 30 1991 21:214
    Yes, I understand now what you meant.  So sorry, beg forgiveness.
    
    len.