From: narpet@cs.mcgill.ca (Greg WARD)
Newsgroups: rec.music.cd,rec.audio
Subject: Re: MiniDiscs -- What Are They?
Date: 12 Dec 92 04:03:40 GMT
Organization: SOCS - Mcgill University, Montreal, Canada

In article <1992Dec9.020926.24735@mnemosyne.cs.du.edu> ramid@nyx.cs.du.edu (Rudy Amid) writes:
>schweda@iastate.edu (Christopher Schweda) writes:
>
>>I apologize if this is a FAQ, but:
>
>  Ditto.
>
>>I was in my local university bookstore and saw a huge display for MiniDiscs.
>>They were on sale for $11.99 and looked like little rectangular
>>boxes a little thicker than CD jewelboxes. My queestion is this:
>>What are MiniDiscs? Why are they cheaper than CDs (since they seem to
>>have all the same titles as CDs -- this display had lots of stuff
>>from Sony/Columbia -- Springsteen, Joplin, etc. etc.) How much do
>>MiniDisc players cost?
>
>  I received my latest copy of Time Magazine, and Sony has this 6 page
>insert of their new MiniDisc player.  It's looks like an amazing new
>technology:
>
>- 2.5" Magneto Optical Disc, cased in hard plastic like that of a 3.5" computer
>  floppy disk.

The technology itself isn't particularly amazing -- monstrous-capacity
magneto-optical drives and discs have been available for computers for
some time now.  What Sony has done is to 1) miniaturize the disc (I
*believe* computer MO discs are usually 5" or 12", just like CD's
or LD's) and package it into a (presumably) convenient form, 2) make
the hardware more affordable, and 3) compress the data.

I really don't know how much "amazing new technology" is required; Sony
just put it all together and will probably make a bundle.

>
>- 74 minutes, CD quality, and (get this) recordable!

Don't assume the quality will be equal to CD in every case.  The data
on a MD is compressed roughly 5:1 using a lossy compression scheme --
that is, decompression does *not* equal data recovery.  It merely
recovers an *approximation* to the original data, which SHOULD sound
the same as the original.  If the psychoacoustic models used in
devising the compression scheme are accurate enough, MD will probably
have perfectly fine sound for the applications it's aimed at: car,
walkman, boom-box, etc.  Let's face it -- do you REALLY notice all
the dynamic subleties conveyed by a good CD when you're driving or 
walking around?  In addition to the background noise, there're a helluva
lot more distractions than when you're sitting in a quiet room at home
with your main system.

Seems to me that MD is a pretty good idea on these grounds (i.e. it 
may not sound as good as CD, but who's gonna notice?), as well as 
convenience (ever notice how awkward stuffing CD's into coat pockets
is?), resistance to bumps and shocks (due largely to a 1 MB buffer
in the player rather than vastly improved mechanical systems, I gather),
and recordability.  *I'm* certainly not going to buy a player for
$700, and I'll keep buying music on CD's as long as I can -- which will
probably be a good long time.  However, I think a $150 or $200 portable
MD player with a few custom-made discs of favourite tunes would beat
the pants off trying to haul CD's and a portable CD player around.

	Greg Ward (narpet@binkley.cs.mcgill.ca)
Newsgroups: rec.music.cd