SH Spotlight CD & Digital flaws: Our technique for finding A/D & D/A converters for DCC Golds in 1992

Discussion in 'Music Corner' started by Steve Hoffman, Jun 6, 2008.

  1. Steve Hoffman

    Steve Hoffman Your Host Your Host Thread Starter

    In the months before the DCC Gold CDs were going to be mastered at Location Recording Service back in 1992, Kevin Gray was upgrading the mastering room and searching for a new A/D, D/A system to get more resolution than the old Sony PCM system could give us.

    Kevin had a nifty vintage EMT stereo echo/reverb plate in the back of the studio and what he did was to record a bunch of "taps" with a drumstick onto the top of the console using his vintage Neumann mic with full reverb up so we could hear the echo trail decay. He recorded them on 15 ips tape and then we cut a lacquer of the numerous reverb hits as well. (Yes, this was as boring as it sounds).

    We compared the decay time of the lacquer with the "master" analog tape. They matched. Next step of course was to compare the Sony digital PCM-1630 recording of the tape with the lacquer. Surprise (not), they didn't match. The digital master decayed much earlier and the reverb wasn't accurately reproduced to begin with (a common problem back then). It was there, just not ALL there.

    So, that was our "standard ref" in the goal to upgrading the digital recording system; to find a machine that could record and play back the echo hits in digital so they would match the lacquer in intensity and decay. The unit with the most ambiance retrieval would win.

    After MUCH searching, Kevin found a Wadia professional unit that was a big improvement on the Sony PCM system. After some proprietary tweaking by Kevin, the Wadia was installed in the system right before I started on the first DCC Gold, "Wheels Of Fire" by Cream. We used that all through the LRS masterings and Kevin took it with him when he switched back to Future Disc Systems in the middle 1990s.

    Kevin did the same test at AcousTech when he upgraded to what he has now (Pacific).

    I bring this up not as a digital vs. analog thing but to show that engineers around the world realize the problems that PCM digital has had from the start. We want it to match analog playback and have struggled for 25 years to get it. It's close but not perfect. Can you tell? Dunno. Depends on your playback system and your personal hearing system (yer EARS). You might not care; CDs are so much easier to play.

    So this is not a new thing, but this is something that we WANT to sound as good as it can. Digital has come a long way but it's not perfect (in the "good" way).
     
    snkcube, mwheelerk, vonwegen and 8 others like this.
  2. -Ben

    -Ben Forum Resident

    Location:
    Washington DC Area
    Back in the 90s I borrowed a Wadia 17/27 transport-DA combo, had it in my room for an hour or so. I played one of the DCC McCartney CDs and the sound just blew me away. The Wadia was doing something that just sounded so much better than I've ever heard since or before regardless of what CD player I use.
     
  3. raunchy

    raunchy New Member

    Location:
    Canada
    I remember reading a quote by a famous mastering engineer (name escapes me at the moment) who claimed digital would have to approach 250 khz sampling rate or some high number to be closer to the analog sound. Who knows, but at least it kind of puts it in perspective.
     
  4. Plan9

    Plan9 Mastering Engineer

    Location:
    Toulouse, France
    Wasn't it what DSD is trying to achieve by sampling at 2.8 Mhz?
     
  5. tps

    tps Active Member

    Location:
    Philadelphia, PA
    Maybe we need more than 16 bits of resolution...
     
  6. bdiament

    bdiament Producer, Engineer, Soundkeeper

    Location:
    New York
    Hi Steve,

    Sounds like a great way to test.

    I also use the sound of a "space" I know well, with two-mic recordings I made myself. Along with changing the reverb characteristics and the length of the decay, not many A-Ds can even keep the space in focus.

    The Pacific does a great job. Some of the new Sonic boxes (e.g. the 305) along with another one I'm testing (which I can't name right now) have, to my ears, achieved new levels of fidelity to the mic feed.

    Best regards,
    Barry
    www.soundkeeperrecordings.com
    www.barrydiamentaudio.com
     
  7. Steve, did the 1630 converters get the tonality right? Have you run across converters that couldn't get either (tone or spacial quality) right? Do the newest converters affect how you master at all? Thanks.
     
  8. Metoo

    Metoo Forum Hall Of Fame

    Location:
    Spain (EU)
    Steve, would you say that this shortcoming of digital is solely a resolution thing, or could there be something else at play? BTW, did you try different sampling rates and bit depths in the tests you mention? If so, what was closer to the analog?

    I agree with you that digital has come a long way. It is a pity that more professionals today are not interested in getting the best sound out of it instead of just going for the 'sound of the moment' because perhaps that would help digital achieve more in less time. (Just MHO).
     
  9. Steve Hoffman

    Steve Hoffman Your Host Your Host Thread Starter

    Agreed, Barry. Now is a good time to be getting into digital. Too bad CD's are done for; just starting to get it real right without our mastering "tricks"!:(
     
  10. Steve Hoffman

    Steve Hoffman Your Host Your Host Thread Starter

    I've never heard a professional converter that did NOT get the tonality correct. Never. That (to me) has never been the problem.
     
  11. Steve Hoffman

    Steve Hoffman Your Host Your Host Thread Starter

    Back in 1992 there was really only one rate. We could only test the gear that existed in the real world made for studio use. There was nothing else.
     
    ElevatorSkyMovie likes this.
  12. LesPaul666

    LesPaul666 Active Member

    Location:
    New Jersey
    I think for the most part, it's the quality and resolution of the converters, even at 16/44.1. Ya just need to spend the bucks.:D
     
  13. Metoo

    Metoo Forum Hall Of Fame

    Location:
    Spain (EU)
    You are right. I forgot that you were working on the DCCs back in '92.
     
  14. blind_melon1

    blind_melon1 An erotic adventurer of the most deranged kind....

    Location:
    Australia
    It's a shame, from what I've read vinyl had never sounded better before it started to disappear...

    Re the first post by Steve, I'm amazed by the dedication that goes into your masterings, not just by you, but the crew around you. Every little (and big!) bit/decision counts... (Every little BIT counts with digital) :) .. and it really shows in the final product. I may not be able to afford a lot of the OOP stuff, but when I do buy them I am blown away every time..

    Thank you.
     
  15. Additional curse: you get it right with the Wadia A/D-D/A and
    the cd manufacturing process itself introduces problems (degradation).
     
  16. bdiament

    bdiament Producer, Engineer, Soundkeeper

    Location:
    New York
    Yeah.
    I remember back in '83, I was telling folks we'd had vinyl disks for close to 100 years (at the time, I think 95 was the exact number). I used to say "Just wait. In another 100 years CDs will sound at least as good." :rolleyes:

    Best regards,
    Barry
    www.soundkeeperrecordings.com
    www.barrydiamentaudio.com
     
    Hamhead and hi_watt like this.
  17. LeeS

    LeeS Blue Note Fan

    Location:
    Atlanta
    I've defintely noticed a big improvement in ADCs and DACs over the years.
     
  18. LeeS

    LeeS Blue Note Fan

    Location:
    Atlanta
    We sure do. Once you hear 24/176 of a recording and compare it with even good 16/44.1, you realize it is no contest.
     
  19. ubsman

    ubsman Active Member

    Location:
    Utah
    I'm still using my ancient Wadia from 1992 or so. Still sounds good to me. Only problem is it doesn't go any higher than 16/48 so can't play some of the newer stuff through it.
     
  20. LeeS

    LeeS Blue Note Fan

    Location:
    Atlanta
    Wadia makes good gear but have you heard the newer models?
     
  21. ubsman

    ubsman Active Member

    Location:
    Utah
    Nope, there's no high end stores around here anymore. They've all switched to "home theatre" installation companies.
     
  22. LeeS

    LeeS Blue Note Fan

    Location:
    Atlanta
    In Atlanta they are going back to good ole 2 channel audio! :cool:
     
    McLover likes this.
  23. KeithH

    KeithH Success With Honor...then and now

    Location:
    Beaver Stadium
    Steve, thanks for sharing. Despite the technological advances, the CD format is all dressed up with no place to go. :(
     
  24. JA Fant

    JA Fant Well-Known Member

    LeeS,
    could I get info on the stereo shops in ATL?
     
  25. LeeS

    LeeS Blue Note Fan

    Location:
    Atlanta
    Sure. Try:

    Sound & Cinema in Alpharetta
    Audio Alternative in Lilburn
    Audio Atlanta in Marietta
    Georgia Home Theater in Smyrna
    Gateway Sound in Tucker
     
    McLover likes this.

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