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Here is the URL to a technical paper concerning DSD.
http://www.dmprecords.com/images/dsd.pdf
Here is a tech-talk about the first DSD recordings made by DMP
http://www.dmprecords.com/techtalk/Default.htm
DMP records has allready made two DSD albums available for purchase.
http://www.dmprecords.com/releases/newdsd.html
----- Oorspronkelijk bericht -----
Van: Kade Hansson <[EMAIL PROTECTED]>
Verzonden: maandag 19 juli 1999 03:13
Onderwerp: Re: MD: MDs, PCM audio, Super CDs and DVD-Audio (OT)
> At 11:40 PM 7/17/99 -0700, you wrote:
> >Let me de-lurk here for a moment and ask a totally newbie question:
> >
> >What is PCM Audio? Isn't it the format that DVDs use for audio?
>
> It's a fancy name for signed linear uncompressed audio. The typical sample
> rate is 44.1kHz, with the waveform represented by 15 bits of amplitude and
> one bit of sign. It is the format used by CDs, and while such sounds are
> possible on DVD, they do limit the bit rate available for the video, they
> are usually retired in favour of compressed formats like MPEG, DTS and
> Dolby Digital, which also have the advantage that they are well adapted to
> presenting surround sound.
>
> >Also, does anyone know what Super CD and DVD-Audio is? My company
> >will begin carrying Super CD and DVD-Audio decks in late 99-2000 (I
> >think). I've heard Super CD and DVD-Audio are supposed to sound much
> >better than CDs (and MDs, I assume). How is that possible? I thought
> >the regular CDs sampling rate already picked up every possible
> >frequency that the human ear can hear. How will these new formats
> >improve upon the current? And -- most importantly -- will they be
> >compatible with MDs (no copyright lockout)?
>
> Well, DVD Audio has only just been formalized, and details are only
readily
> available to members of the "standardization" organization. It is
> supposedly part of the "acoustic audio renaissance". For years, devoted
> audiophiles have been complaining that CDs are too "sharp" sounding and do
> not present the "warmth" of vinyl records. I personally find this
> ridiculous- vinyl is clearly a distorted impression of the sound- and it
is
> my belief that a vinyl record, suitably filtered, and recorded onto a CD
> (or MD), would exhibit no difference to a listener accustomed to this
> warmth. i.e. The effect is probably a desirably familar distortion, not an
> advantage of analogue sounds over digital sounds.
>
> However, there may be a case to answer in terms of distortion present on
> CDs and other 44.1kHz 16 bit PCM audio media. There are two forms of
> distortion here- quantization distortion (the 16 bit part) and waveform
> distortion (the 44.1kHz part). For my money quantization distortion is
> vanishingly low at CD quality, because 66536 steps should be more than
> enough to reproduce a smooth waveform to all ears (caveat being that soft
> sounds have fewer steps available in this linear scheme). However, there
> may be a case to answer in terms of waveform distortion.
>
> A 22kHz sine wave is on the fringe of human heaing. However, a CD will
> convert this to a square wave, and waves slightly above and below this
> sound level will be indistinguishable, wheras there are perhaps
perceivable
> differences to analogue waveforms around this level. This extreme example
> (which is hardly relevant to your average listener, who has more problems
> in their amp than from digital artifacts) does also present an effect in
> all high frequencies, though to a significantly lesser extent. A steep
sine
> wave simply cannot be accurately represented at a 44.1kHz sample rate,
> which has the number crunching audiophiles up in arms.
>
> Whether the reality is that the human ear percieves these mishmashed
square
> waves as different from corresponding sine waves is debatable. However, to
> appease the audiophiles, and to present a possibly new wave of the
> lucrative "I already have that on media X, but on media Y it will sound
> better" rebuying scenario, the record companies are taking advantage of
the
> density of DVD media to present sound at the limit of what is digitally
> feasible today.
>
> "DVD-Audio supports a wide range of digital audio options: PCM and
> MLP decoding are mandatory for all players. Discs may use either on a
> track-by-track basis. Sampling frequencies may include 48 kHz, 96 kHz,
> 192 kHz, and 44.1 kHz, 88.2 kHz, 176.4 kHz. DVD-A can have bit
> resolution of l6-, 20-, or 24-bit. With MLP the precision may be
selected
> between 16 and 24 bits in 1-bit steps. Up to six channels are available
for
> multichannel recording, with a transfer rate of 9.6 Mbps. Many provisions
for
> providing 2-channel and multichannel mixes. High compatibility with the
> DVD-Video and DVD-ROM formats."
> - http://avacademy.com/news/stories/06_03_99_01.html
>
> There are also possibilities for directly encoded 6 channel sound (akin to
> surround schemes like DTS and Dolby 5.1, except there is no compression),
> which is a definite benefit over CD. This is somewhat ironic given that
> such high sample rates would have been sufficient to allow a highly
> directional form of Dolby ProLogic to be used, even for high frequency
> effects- phase differences would be much more readily represented given
the
> increased resolution.
>
> How DVD-A is used in practice... well, we'll have to wait and see. And
that
> wait could be quite significant- we have already waited some 5 years for a
> standard to emerge. Which leads us to yet another "competing formats"
> scenario, although it may be true that it has already been won and lost.
>
> As you have alluded to, Sony in partnership with Ph*l*ps has a little
beast
> called Super Audio CD. Essentially, a DVD by another name, this format
> ditches PCM altogether in favour of something called DSD...
>
> "The Super Audio CD employs Direct Stream Digital as
> the fundamental recording technology. DSD uses a
> sampling rate of 2.8224 MHz to record a 1-bit signal
> directly, thereby eliminating the need for decimation
> filtering in the recording process and interpolation filtering
> in the playback process. Thus, according to Sony, the
> resultant digital signal very closely resembles the shape
> of the original analog waveform.
>
> Sony said it has achieved a theoretical playback
> frequency range of up to 100 kHz and a dynamic range
> in excess of 120 decibels across the audible range."
> - http://www.techweb.com/wire/story/TWB19990409S0004
>
> Which is probably lifted directly from Sony/Ph*l*ps press kit. I notice
> they have used a scheme not directly comparable to linear PCM (as found in
> CD and DVD-A), which could bambuzle the public was there to be a media
war.
> But it seems like Sony and Ph*l*ps have already resigned to failure, as
> both will support DVD-A immediately. The big advantage that Super Audio CD
> was to have over DVD-A has been ditched- that is, a CD compatible layer
> which would allow backwards compatibility with existing CD equipment.
>
> Super Audio CD looks set to be a novelty or very high end format at best,
> and a stillborn disaster at worst. Then again, DVD-A is not guaranteed of
> instant uptake either, and it too may fall flat. I have a suspicion that
> DVD-A might be popular for another reason- if it is possible in the spec
to
> have 44.1kHz PCM at 16 bit resolution (which seems to be the case), I
think
> it may be popular to have "super compilations" which run for many hours,
> perhaps rivalling CD changers. The problem, of course, will be the
> licensing hurdles and how such media are priced.
>
> Anyway, sorry for the OT nature of all this, but it was asked. And it is
> kind of relevant to MDers, who record from a variety of audio media...
>
> Cheers,
>
> Kade, who's getting a DVD player this week- digital recordings at last!
>
> --
> Archer
> http://www.geocities.com/SoHo/6413/
>
> End.
>
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