Based on 20 years of testing, a "high quality" replica has lower error rates
and jitter, and higher reflectivity than a "high quality" recorded CD-R.
CD-R discs have a tighter unbalance spec. However, variations between lots,
between manufacturers, and between CD-R writers and write speeds are greater
than differences between media types. Our tests cover all of the
Red/Yellow/Orange Book requirements that are too numerous to list here.

Jerry
Media Sciences, Inc.

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of Tom Fine
> Sent: Friday, January 04, 2008 10:18 PM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] CD-R question
> 
> Well, it may well be argued that 80-minute is out of spec with the 1982-
> ish Red Book, but in
> practice commercial CDs of more than 74 minutes have been released on a
> somewhat frequent basis
> since at least the late 1980's. So, by the time CDR media became available
> to the masses, any
> respectable player that could read a CDR in the first place should have no
> more trouble with a
> 80-minute vs. a 74-minute. I did say respectable player, as I've had
> cheapo portables and early
> automobile players that had trouble with 80-minute media.
> 
> Mike, when you say "we know that they have higher error rates and are
> harder to read than equivalent
> 74s," can you explain how we know this? How many different tests at
> different times by different
> people are you citing as evidence? Also, are these results several years
> old or recent (or both),
> and comparing 74- and 80-minute products of the same dye types and same
> manufacturers at the same
> time? Not picking on your assertion, just trying to find out how
> scientifically rigorous this
> widely-bandied assertion about 80-minute media is.
> 
> Finally, the error rates detected, how did they compare with random
> samples of commercially-produced
> music CD's?
> 
> -- Tom Fine
> 
> ----- Original Message -----
> From: "Mike Richter" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, January 04, 2008 8:28 PM
> Subject: Re: [ARSCLIST] CD-R question
> 
> 
> > Tom Fine wrote:
> >> So then no one really knows if 80's are less reliable? If this
> "reliability" issue is mythology,
> >> why is so common on this forum? I ask because 650 meg media is becoming
> somewhat rare and oftem
> >> much more costly. If there is no proven advantage then it is silly to
> insist on it, as some
> >> clients do.
> >
> > No. We know that they have higher error rates and are harder to read
> than equivalent 74s. We know
> > that high error rates and poor readability typically precede failure in
> typical discs. But I know
> > of no stronger reason to believe that 80s are less reliable than 74s.
> >
> > To save a separate thread, some notes may be in order on the standard
> lengths. The standard for
> > pitch on the spiral of a CD leads to 74 minutes' recording time.
> Manufacturing tolerances being
> > what they were two decades back, tolerance on the pitch demanded that
> the player handle pitches
> > corresponding to 63 through 80 minutes. More than a decade ago, TDK
> offered an 80-minute CD-R at
> > prohibitive cost; it lasted some time in the catalogue, but was
> unavailable in practice.
> >
> > Any longer blank is out of spec. Indeed, it may be argued that any over
> 74 minutes is out of spec.
> >
> > Mike
> > --
> > [log in to unmask]
> > http://www.mrichter.com/
> >