Path: utzoo!attcan!uunet!husc6!bbn!gatech!hubcap!ncrcae!wte
From: wte@ncrcae.Columbia.NCR.COM (Bill Eason)
Newsgroups: sci.electronics
Subject: CD Player Questions
Message-ID: <3385@ncrcae.Columbia.NCR.COM>
Date: 25 May 88 13:12:54 GMT
Reply-To: wte@ncrcae.Columbia.NCR.COM (Bill Eason)
Distribution: na
Organization: NCR Corp., Engineering & Manufacturing - Columbia, SC
Lines: 36

(Maybe rec.audio would be better for this, but I'm an engineer who has had 
his fill of audio salesman talk.  Read on...)

I have been shopping for a CD player at a distance until yesterday, and
the salesman I had couldn't answer my questions to my satisfaction.  First,
in terms of CDs, what is x-times oversampling?  My salesman explained that
the player scans the disk four times rather than just one so that it will
get "all the information on the disk.  This gives you more harmonics
than you would get without oversampling."  My understanding is that
the sound on CDs is already sampled at 16 bits, 44.x kHz.  This should be
plenty to cover the audible range.  Any harmonics over this wouldn't make 
a whole lot of difference, would they?  Surely the CDs aren't digitized at
88.x or 176.x kHz, are they?  If not, then does oversampling mean simply 
that the player scans the same bits of the 44.x kHz more times, possibly
as an error correction/detection scheme?  Would a non-oversampling player
miss so many bits to make a difference?  Help!

When I asked about the number of lasers tracking (something most ads hype),
the salesman told me that CD player makers "...found that the number of lasers
really didn't make any difference in how well the disc was tracked."  By
the time that sentence got past my ears, it sounded more like "We don't carry
any models with that feature."  What do netters think?

Finally, the player had an RCA jack marked as digital out.  Anybody know about
the serial format or how to tap into this?  The specific player being pushed
was a Magnavox 560, I believe, for $188.  How does this sound?

"Anything you could do to help us would be . . . helpful"
                                             - Monty Python and the Holy Grail

TIA,  Bill Eason    ...!ncr-sd!ncrcae!util5!wte
-- 

Bill Eason   (803) 791-6917    ...!ucbvax!sdcsvax!ncr-sd!ncrcae!util5!wte
NCR Corporation		  ...!rutgers!mcnc!ece-csc!ncrcae!util5!wte
E & M Columbia   3325 Platt Springs Rd.   West Columbia, SC  29169