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Conference cookie::notes$archive:cd_v1

Title:	Welcome to the CD Notes Conference
Notice:	Welcome to COOKIE
Moderator:	COOKIE::ROLLOW

Created:	Mon Feb 17 1986
Last Modified:	Fri Mar 03 1989
Last Successful Update:	Fri Jun 06 1997
Number of topics:	1517
Total number of notes:	13349

465.0. "mono = time > stereo ?" by USRCV1::CARNELLP (Fanmail from some flounder) Sat Sep 20 1986 14:31

    Note 464 wandered off onto the subject of whether a mono recording
    should play longer than a stereo recording. Rather than continue
    to clutter up 464, I started this note to continue the discussion.
    
    From resent articles I have read, it sounds as if the new CDI format
    has this capability. There are also two type of mono, a hi-fi mode
    for music and a lo-fi for less demanding material. They claim
    that lo-fi will hold 24 hours of material on one disk.
    
    I know this doesn't help the discussion concerning the current
    format. As I understand it, the current format allows for only
    one encoding method. If you want mono then you have to encode two
    identical channels.
    
    Paul.

T.R	Title	User	Personal Name	Date	Lines
465.1	Freewheeling	BISTRO::HEIN	Hein van den Heuvel, Valbonne.	`Mon Sep 22 1986 04:15`	15
	<<< PYRITE::SYS$SYSDEVICE:[NOTES$LIBRARY]CD.NOTE;1 >>> -< CD Discussions >- ================================================================================ Note 464.8 MOWTOWN - Rules again !!! 8 of 8 BISTRO::HEIN "Hein van den Heuvel, Valbonne." 7 lines 22-SEP-1986 04:11 -< Mono=Longer. Freewheeling. >- -------------------------------------------------------------------------------- Yet another comment about mono=longer. It could ofcourse be done within the current standards by recording on album say on the left channel and another, totaly independendly, on the right channel. When playing such an CD rip out the in-appropriate channel connector and switch the amp to mono. A trivial switchbox between the CD and AMP could provide those functions with one button. I hope they will never do it!
465.2	Is 24 hours even possible?	MERLYN::BILLMERS	Meyer Billmers	`Mon Sep 22 1986 13:28`	15
	re: .0 24 hours on one disk! Maybe I'm missing something, or maybe the following argument is flawed, but what's wrong with this reasoning: stereo current-fi gets you 1 hour (order of magnitude approximation) of recording per disk. mono high-fi gets 2 hours. To get 24 hours we need about 3 powers of two more. But even with 16 bits encoded for high fi, this means low fi would have only 2 bits (to get 8 times as much space). Two bits isn't low-fi, it's noise. Am I missing a crucial bit of logic here?
465.3	24 hrs - lets see	ERIE::FARNSWORTH		`Mon Sep 22 1986 14:14`	13
	Remember, the CD encoding results in almost 3 times as many bits out as went in. Then, companded 8 bits (like 8 mm vidio's audio) is too bits, for low-fi. And finally, the clock could be cut in half, maybe more (what was the band pass). Just speculating! You could probably fix it up some ( like oversampling) after you did this to it. Anyway, 24 hrs sounds about right, but NOT good! Ed