16 bit vs 1 bit vs 24 bit da converters or I slept through the 90's :)

Discussion in 'Archived Threads 2001-2004' started by Chris PC, Apr 27, 2002.

  1. Chris PC

    Chris PC Producer

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    Excuse me for sleeping through the audio technology of the 90's, but what ever happened to 1 bit d/a converters? I remember how my first original CD player has dual 4 times oversampling 16 bit d/a converters, but then I recall after going with 18 20 and 22 bit converters they went to a 1 bit converter and 16 times oversampling [ not really oversampling since it takes 16 samples to get 16 bits [​IMG] ] At least, thats what Matsushita did with their MASH technology. So how come my Marantz receiver contains 24 bit D/A converters instead of a 1 bit 16 times oversampling converter? I thought the 1 bit technology of d/a converters were more widely adopted.
    How many times oversampling does my receiver do? Only two times at 96 khz? Does Technics and Panasonic still use the 1 bit MASH technology?
     
  2. Sihan Goi

    Sihan Goi Second Unit

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    There are many kinds of DACs(1-bit, multi-bit, sigma-delta, ladder, etc) and they can't be compared directly since they use different algorithms for the conversion. Also, the new DSD DACs are an entirely different animal too.

    The "24bit" in DACs mean that they can resolve the amplitude range to 24 bits, or around 16.7million levels. This allows greater dynamic range and SNR than 20,18 or 16bit DACs. The 96KHz portion means that it samples 96000 times per second, and this allows the frequency range to exntend to around 48KHz by Nyquist's Theorem.
     
  3. Chris PC

    Chris PC Producer

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    Right, I guess that makes sense. Out of curiosity, how can you use a DAC of 18,20,22 or 24 bits when CD's are technically recorded as 16 bit? Doesn't that mean they only have a maximum word length of 16 bits? Or does using a DAC with a greater # of bits have to do only with the dithering or are there actually words longer than 16 bits on a CD. I'm not clear on that.
     
  4. Sihan Goi

    Sihan Goi Second Unit

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    Well, its not only for CDs. Its for DVD-A as well, and DVD-A can be 24/96 IIRC. Also, they do things like dithering and stuff to get a pseudo 18/20/24bit sample if I'm not wrong.
     
  5. Jeff D.

    Jeff D. Supporting Actor

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    Chris;

    You are correct in your thinking. All redbook CDs are 16-bit and that will never change. When people see a machine with a 24-bit D/A, they get excited because they think they are getting true 24-bit sound. Of course they aren't, because the disc is still 16-bit.

    Single bit D/As tend to create (as part of their algorithms) a huge amount of ultrasonic noise. This can make them a little trickier to partner with amps - as some amps are more susceptible to this kind of interference. This can make the CD/amp combo particular important, sonically. Generally, multi-bit converters are more compatible, since they do not produce as much ultrasonic noise.

    /Jeff
     
  6. Chris PC

    Chris PC Producer

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    So am I correct in thinking that the DA converters in my SR6200 receiver are only running at 2 times oversampling? My old Sony 5 disc is 4 times oversampling and I remember at least a few cd players back in the late 80's early 90's had 8 times oversampling. I think they didn't go to 16 times, except of course, for the 1 bit D/A converters.
     
  7. Chris PC

    Chris PC Producer

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    So what is the DA converter in my Marantz SR 6200 receiver then? Anybody? What technology does it employ?
     
  8. RussS

    RussS Auditioning

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    Sihan Goi,

    Would you know a website where I can learn the basics of the differences between 1-bit, multi-bit, sigma-delta, ladder, DSD, etc. in layman's language.

    I'd like to understand the effects of DAC "architecture" on practical, perceivable sound as well as the implications in terms of matching equipment (e.g., source to amp) and accessories (e.g., interconnects).

    Thanks!
     
  9. Sihan Goi

    Sihan Goi Second Unit

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    RussS, unfortunately I don't. I was actually looking for one before I posted my first reply, to confirm what I was going to post just to make sure I didn't make any mistakes, but I didn't, which is why I kept my post as non-technical as possible, while still providing some information. I took a college class a few years back on electronics, which covered some DAC/ADC principles and material(not audio specific), but unfortunately I've returned much of that knowledge back [​IMG]
     
  10. Larry B

    Larry B Screenwriter

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    Russ and Sihan:

    Chung, who often posts on this forum, is extremely knowledgeable about audio electronics. If you make sure he sees this post, Im pretty sure he'll be able to help.

    Larry
     

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