From: crh@wam.umd.edu (Craig Hinners)
Subject: Re: Sony D-515 opinions?
Organization: University of Maryland, College Park
Date: Mon, 23 Nov 1992 07:01:12 GMT

yxl5388@ultb.isc.rit.edu (Y.X. Liu) writes:
>
>I'm thinking about replacing my current portable CD player with Sony's
>D-515. I noticed in ads that the D-515 has ESP (electronic shock
>protection) which is also present on the MD. Are they using identical
>technologies? Can someone who has this player give me some opinions and
>how much you paid for it? The prices I see right now is around $450.

I have owned a D-515 for about 2 months now and use it extensively in
my car.  To sum it all up, the thing simply doesn't skip.  It works
beautifully in the car and when you walk around with it.  It's about 
time they used this technology on CD's, I feel.  Sony also did an A-1 
job on the construction of this unit.  The thing is solid and a tad   
heavier than your average portable.  No plastic here!

The backlit display is also a nice touch.  There's also a remote control
on the headphone cord (supplied) which even has its dedicated LCD 
display (!).  The headphones they supply with it are those stick-in-
your-ear-canal types with the Gawd-awful bass response which I
really detest.  I think they could have at least supplied an
el-cheapo over-the-ear type with this high-end unit.

Differences between the D-515 and MD?  Well, the D-515 doesn't use data
compression like the MD does.  It simply _reads_ uncompressed data at
a higher speed and puts it in a buffer where it is held until the proper
moment.  This lack of compression avoids certain frequency changes
which are present, if not audible, on MD.  The music you hear on the D-515
with ESP on is the exact same as you would hear with ESP off--or, if you 
prefer, on a "normal" CD player.

With ESP mode ON, there are some things I've noticed with the D-515 that
differ from "normal" CD operation.  For one, when entering either
forward or reverse search mode within a track, there is a slight pause
in the music that occurs between the time the music changes from normal
speed to 2x speed, or whatever the search speed is.  To understand this,
imagine you are hearing the 2nd minute, 32nd second of a track.  Since
ESP is on, the laser is at, say 2:34.  When you press the button to do
a "search", the laser has to go back to 2:32, so that the search starts
from the point of music that you were last listening to.  With ESP
mode OFF, this pause does not occur.  

To get picky, the D-515 only has a 3-second buffer compaired to MD's
10-second buffer.  I'd be hard pressed to find a road where I'd 
need those extra 7 seconds of buffering, though (outside of 
Pennsylvania, that is).

I have noticed that certain blemishes on the disc are "noticed" more
in ESP ON mode, presumably because the disc is spinning faster, but
I'm not a 100% on this explaination.  Besides, it really doesn't matter
in ESP mode, because it's back on track before the 3-second buffer 
is expired.

In addition, with ESP ON and programmed tracks are being played, the
jump from one track to another is instantaneous.  Say you've programmed
the D-515 to play track 1, then jump to track 17.  As soon as you hear 
the end of track 1, the laser is already at 17 reading info., eliminating
dead air.

Also, when switching between ESP ON and OFF, there is less than a second
of silence while the disc either speeds up or slows down.

I payed ~$480 for the D-515, but if you don't feel the need to be the
first on your block to own every toy like I do, wait for the prices
to drop as Christmas approaches.

Craig Hinners  ***  crh@wam.umd.edu

Newsgroups: rec.audio