EAC Issue

[Cougat]

Hello

I just joined the group. I've been using EAC for the past two months and have been very satisfied with the results. Until now. I recently extracted a few songs from an older CD by Eric Clapton, Slowhand (1977). When I played back the WAV file for Lay Down Sally, I noticed that audio data was definitely missing. The guitar solo layed over the rhythm track was no where to be found. I tried extracting the song again with the same result. I even tried extracting the file using compression: same result. I went so far as to download two other applications, WinDAC and CDex. In each case, using these other programs, certain audio information from Lay Down Sally (and, presumably, from other songs extracted from this CD) was missing. Any suggestions?

Cougat

[Non-text portions of this message have been removed]

[Mike Richter-2]

Cougat wrote:
> Hello
>
> I just joined the group. I've been using EAC for the past two months and have been very satisfied with the results. Until now. I recently extracted a few songs from an older CD by Eric Clapton, Slowhand (1977). When I played back the WAV file for Lay Down Sally, I noticed that audio data was definitely missing. The guitar solo layed over the rhythm track was no where to be found. I tried extracting the song again with the same result. I even tried extracting the file using compression: same result. I went so far as to download two other applications, WinDAC and CDex. In each case, using these other programs, certain audio information from Lay Down Sally (and, presumably, from other songs extracted from this CD) was missing. Any suggestions?

 From the fact that other programs are giving similar results, it's
clear that the issue is with the disc, not with EAC. It may be
non-standard - more precisely, not a CD-DA - in many ways. If it is a
commercial disc with the CD logo, that should not be; if it's something
else, it may be.

Mike
--
mrichter@...
http://www.mrichter.com/

[Cougat]

Thanks, Mike, for your insight and for replying in a timely manner. I appreciate your help. As far as I know, the Slowhand CD disc is a legitimate product from PolyGram Records. I purchased it used from a music store. Oh well. It's not the end of the world. I have plenty of other commercial music CDs on hand from which to draw material. I will continue to use EAC.

Sincerely,

Cougat

[Non-text portions of this message have been removed]

[Cougat]

What is the advantage-- if any-- using a slower burn speed? While the drop-down menu in my version of EAC allows me to use the 48X speed, I always opt for the slowest speed available (8X) thinking that quality might be optimized. Any validity to this idea?

Cougat

[Non-text portions of this message have been removed]

[Mike Richter-2]

Cougat wrote:
> What is the advantage-- if any-- using a slower burn speed? While the drop-down menu in my version of EAC allows me to use the 48X speed, I always opt for the slowest speed available (8X) thinking that quality might be optimized. Any validity to this idea?

There is an optimum burn speed for any combination of medium and writer.
For most modern products, it's in the range 8-16x. Error rates go up
rapidly outside that range (either faster or slower) and such discs are
also likely to go bad more quickly.

It's easy enough to measure for the optimum if you can read C1 as well
as C2 errors (i.e., on some Plexwriters), but even without that you can
use CDSpeed or a similar tool to find out where you prefer to write.

Mike
--
mrichter@...
http://www.mrichter.com/

[Cougat]

Thank you, Mike, for your insight and expertise.

Cougat

[Non-text portions of this message have been removed]

[Nick Sciurba]

Is any information available on using the results from CDSpeed?
I found
http://club.cdfreaks.com/f96/cd-dvd-speed-user-guide-192563/#post1540623
, but I'm afraid I don't understand how to interpret the output?

Thanks
Nick



--- In eac@..., Mike Richter <mrichter@...> wrote:

>
> It's easy enough to measure for the optimum if you can read C1 as well
> as C2 errors (i.e., on some Plexwriters), but even without that you can
> use CDSpeed or a similar tool to find out where you prefer to write.
>
> Mike
> --
> mrichter@...
> http://www.mrichter.com/
>

[Mike Richter-2]

nsciurba wrote:
> Is any information available on using the results from CDSpeed?
> I found
> http://club.cdfreaks.com/f96/cd-dvd-speed-user-guide-192563/#post1540623
> , but I'm afraid I don't understand how to interpret the output?

This is rather a quick treatment, but I hope it will serve.

Remember, please, that the purpose is to find the best recording speed -
the one with fewest errors. It is not to have a go/nogo decision on a
specific recording.

Scan Disc gives only very high-level information; any medium/speed
combination which gives yellow blocks should be regarded as
unacceptable. Even if the disc plays back well initially, it is likely
to degrade more quickly than one which is 'clean'.

Disc Quality is the real test - and here you are dependent on the
properties of the drive. The inherent error rate of optical media is
high, of the order of one bit in ten thousand. To deal with that, two
layers of error correction apply in audio (and a third for data). C1
errors are those which get through both layers; there should be none of
those. C2 errors are caught in the first layer and will always be
present. Clearly, the 'best' speed for any medium and drive is the one
that has the fewest C2 errors. If your drive reports C2 errors, then
that is the only measure you need.

Unfortunately, few drives do report C2. Also unfortunately, it takes a
pretty poorly recorded disc to have C1 errors - the ECC is quite strong.
So the best information you can get is from looking at the line showing
speed of reading. It should be smooth with no downward spikes - or at
least few of them. Each of those shows re-reading to get correct
information. The more and the deeper those spikes, the poorer the recording.

Again unfortunately, most drives buffer the data before CDSpeed can read
the results. In that case, there will be few spikes from which to make a
judgement, but usually one can see at what speeds they become more
numerous and split the difference. Thus, at 4x and 24x, there may be
noticeably more spikes than between those two and optimum recording
speed might be in the range of 8-12x.

Mike
--
mrichter@...
http://www.mrichter.com/

[Nick Sciurba]

Thanks Mike.


----- Original Message -----
From: "Mike Richter" <mrichter@...>
To: <eac@...>
Sent: Sunday, July 27, 2008 6:00 PM
Subject: Interpreting CDSpeed (was [eac] Re: Burning Speed)

> nsciurba wrote:
>> Is any information available on using the results from CDSpeed?
>> I found
>> http://club.cdfreaks.com/f96/cd-dvd-speed-user-guide-192563/#post1540623
>> , but I'm afraid I don't understand how to interpret the output?
>
> This is rather a quick treatment, but I hope it will serve.
>
> Remember, please, that the purpose is to find the best recording speed -
> the one with fewest errors. It is not to have a go/nogo decision on a
> specific recording.
>
> Scan Disc gives only very high-level information; any medium/speed
> combination which gives yellow blocks should be regarded as
> unacceptable. Even if the disc plays back well initially, it is likely
> to degrade more quickly than one which is 'clean'.
>
> Disc Quality is the real test - and here you are dependent on the
> properties of the drive. The inherent error rate of optical media is
> high, of the order of one bit in ten thousand. To deal with that, two
> layers of error correction apply in audio (and a third for data). C1
> errors are those which get through both layers; there should be none of
> those. C2 errors are caught in the first layer and will always be
> present. Clearly, the 'best' speed for any medium and drive is the one
> that has the fewest C2 errors. If your drive reports C2 errors, then
> that is the only measure you need.
>
> Unfortunately, few drives do report C2. Also unfortunately, it takes a
> pretty poorly recorded disc to have C1 errors - the ECC is quite strong.
> So the best information you can get is from looking at the line showing
> speed of reading. It should be smooth with no downward spikes - or at
> least few of them. Each of those shows re-reading to get correct
> information. The more and the deeper those spikes, the poorer the
> recording.
>
> Again unfortunately, most drives buffer the data before CDSpeed can read
> the results. In that case, there will be few spikes from which to make a
> judgement, but usually one can see at what speeds they become more
> numerous and split the difference. Thus, at 4x and 24x, there may be
> noticeably more spikes than between those two and optimum recording
> speed might be in the range of 8-12x.
>
> Mike
> --
> mrichter@...
> http://www.mrichter.com/
>
> ------------------------------------
>
> Official Exact Audio Copy web site:  http://www.exactaudiocopy.de/
> Yahoo! Groups Links
>
>
>

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