From: alvin@top.cis.syr.edu (Alvin Leung)
Subject: Re: CD's .vs. LP's (Re: Neighbor's loud stereo
Organization: Syracuse University CIS Dept.
Date: Fri, 20 Nov 92 22:09:44 EST

In article <1992Nov19.193254.3417@shearson.com>, wcheung@shearson.com (Wansan Cheung) writes:
|> lp are better than cds. (NOT!) 
|> lets put it this way, lp are analog by nature and thus tend to be a continuous
|> image of the recorded sound. cds on the other hand are digital which means
|> the signal is sampled at regular intervals. this is like taking a snapshot
|> regularly instead of recording continuously. at first glance, one might think
|> that because lps are analog and contains no discontinuities, they are better.
|> this is not quite true. with the high sampling rate (how many times a second a
|> snapshot is taken of the signal. 44100 times a second) it is extremely difficult
                                                          ^^^^^^^^^^^^^^^^^^^^^^^^
|> for humans to distinguish the discontinuities between each "snapshot". since the
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  Not True.  When the signal is sample at 44.1kHz.  We have enough information to
  recreate part of the original signal, which composed by dc to approx. 22.05kHz
  sin wave.  The results of many medical experiments shows that human typically
  can hear approx. 15Hz to 22KHz (the 1Hz to 14Hz frequency, we generally feel it
  rather than hear it.)  Consequently, digital recording 44.1kHz use as a cut-off.

|> human brain only works so fast, the "snapshots" sort of "blurs" together to give
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   The human brain have nothing to do with it.  The signal is filtered by a
   15Hz to 22kHz band pass filter.
   After the digitially recreated analog signal pasted through the filter, the
   signal is an apporx. of the orignal signal. 

|> the illusion of continuity. [ i could talk about the other fun stuff like aliasing,
|> nyquist thereom and other geeky sounding electrical engineering mumble jumbo but 
|> that's way beyond the scope of this post. :) ]
|> however, there are other issues involved that makes cds better. briefly going down
|> the list:
|> reproducibility. since information is in digital format, you're guaranteed (to the 
|> best of your DAC's ability) exact information every single time.
                ^^^^^
   and the amplifier too.  The major noice sources for a CD is the amplifier
   circuit and the speakers.
|> 
|> durability. nothing comes into physical contact with the media which means that the
|> disc will not get worn with extended use unlike lps.
   ^^^^^^^^
   The signal of LP is contaminated by the scratchy noice, which produce by the
   physical contact of the pick-up pin and the LP. Considering, the sound is
   encoded by the bumps and valleys on the surface of the LP.  Then any material
   deformation contributes to the error of the signal.  We have lots and lots
   ways to cause that unwanted deformation.  When the LP come in contact with
   the pin (ie playing the LP), the material deforms a little.  The material
   change shape, when the temperature change.  You name it, you got it.

   The major noice sources for a CD is the amplifier circuit and the speakers.
   LP also receive similar degree of noice from amplifier circuit and the
   speakers. When compare with the above mentioned noice sources, amplifier
   circuit and the speakers noice is minor.
|> 
|> capacity. notice the size of cd vs lp. consider 1 side as opposed to 2.
|> 
|> convenience. i don't know about you, but i have yet to see a portable battery 
|> powered lp player. [ luggable yes but not portable ] :)
   ^^^^^^^^
   Mainly because of the inconvenient size of LP.  
|> 
|> there are people who might be able to tell the difference between lp and cd
|> [blind taste: which is the cd, a or b ? :)] but those are few and far in between.
|> 
|> personally i like cds. i have over 300 of the suckers and laser discs, did i 
|> mention laser discs ? :~.) <-[cindy crawford smiley]
|> ---
|> just my $0.02 worth.
|> -dave
|> 

Alvin
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