23 Sep
2007
23 Sep
'07
11:28 p.m.
First off, why are you reprising a 4 year old thread if you don't have
anything new to add?
Maitland Vaughan-Turner wrote:
So..? Most PCM converters utilize a 1-bit stream
also. Why not
utilize all the tools available for the task at hand?
Yes, but you need to analyze what you are doing or the next thing
you know you are paying mega dollars for triple gold plated single
direction, rare earth metal interconnect cables and other such
snake oil.
As for processing, you can look at a PCM
representation of a waveform
to ease the processing load and then just apply the changes to the
orignal DSD stream without ever having to process in the 1-bit domain
directly (which is way more processor intensive since you have to look
at a huge chunk of the stream in order to extract the amplitude data
that is available in each multi-bit sample).
Problem : the conversion from DSD and PCM is lossy [0], hence doing
DSD -> PCM -> DSD -> PCM is a bad idea.
IMHO, though, the hippest alternative at present is to
process a DSD
stream in the analog domain and re-record it to DSD.
Two problems:
- A-to-D converters are limited to about 20 bits of SNR due
to things like silicon junction noise and those noisy
electron thingys.
- All commonly used audio A-to-D converters are 1-bit so every
time you go to analogue and then into a digital effects box
you are doing another DSD to PCM conversion.
See reference [0] below.
This results in a very "analog" sound.
So, you have a way of objectively measuring how "analog" something
sounds? I'd be interested in hearing your methodology.
These days you can get analog gear with a
respectable dynamic range for a song (Mackie Onyx anyone?). When you
can get a 130 dB S/N ratio in the analog domain you really don't lose
too much converting back and forth from 1-bit domain.
Where is you analogue to digital converter which also has 130dB SNR?
Erik
[0] Why 1-Bit Sigma-Delta Conversion is Unsuitable for High-Quality
Applications,
Stanley P. Lipshitz and John Vanderkooy
http://sjeng.org/ftp/SACD.pdf
--
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Erik de Castro Lopo
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Fundamentalist : Someone who is colour blind and yet wants everyone
else to see the world with the same lack of colour.