Patrick Dixon wrote:
reeve_mike;131056 Wrote:
Within the limit that any filtering in D/D or D/A conversion is
'guessing' the original analog signal between two adjacent sample
points
- who is to say that it indeed was the smooth transition that the
filter yields ...
You're missing the point, the characteristics of the signal are
determined when you sample the analogue signal: if the original signal
is correctly bandlimited prior to A to D Conversion (or the sampling
frequency is sufficently in excess of twice the bandwidth), then you
know where the 'intermediate' points should be.
Right. Mike doesn't understand (or appears to not understand) the work
of Shannon and Nyquist. All of the digital sampling work is based on
their theories.
Nyquist showed that sampling at twice the bandwidth allows
reconstruction. That is why the RedBook spec uses 44.1 kHz.
For decades, the hfi world used a bandwidth of 20 hz to 20kHz
as the limits of human hearing. Sampling at 44.1kHz allows
a little over.
In reality, very few adult males can hear over about 15kHz,
or at least they are at least 40 dB down above 15 kHz.
Some reasonable folks say that while human's can not hear above
20 kHz, that there is impact of the signal, whether it is phase
distortion, inner harmonics, etc.
Sadly, the format wars between SACD and DVD-A have shown
both the music labels and the electronic vendors that there
is zero market for high-wide music.
There is a tiny chance that dual-disks will keep some DVD-A high/wide
music, but it is pretty low. SACD is dead, as is pure DVD-A.
Now the vinyl folks claim that their systems can do better than
20-20kHz, but getting a needle to physically respond over 20kHz is
at least a huge challenge.
RedBook is what we have, and will have for the next decade or two.
At least until the kids demand quality above MP3s in quantities to make
the labels and studios do something. With all the interest in home
theater, which has poor to terrible sound, I'm not holding my breath.
--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html
_______________________________________________
audiophiles mailing list
[email protected]
http://lists.slimdevices.com/lists/listinfo/audiophiles
