well,
thanks to a guy called raff, I was encouraged to hassle with determination of offsets for my drives.
I have:
Plextor Plexwriter PX-W 8432 A
latest FW 1.09 for 8/4/32 T
(A and T is obviously same hardware and software, lol, who knows the difference between A and T models ?)
Toshiba SD-M 1222 DVD/CD-Rom
latest FW 1004 (not patched to RC-free, original still)
According to coaster factory, satcp,
http://www.ping.be/satcp/eacoffsets01.htm#-
my Plex should have the following offset values:
read offset correction: +355
write offset: -30
According to Plextools:
read offset : -1420 / 4 = -355
write offset: -120 / 4 = -30
The read offset correction of Toshiba was unknown until now !
So, I have had the problem for ages, that I don't own any reference-CD, and I wasn't able to get one, yet.
Well, I own one "reference-CD", Queen - Greatest Hits,
but the wrong pressing...............
And this was the reason, why I never tried to determin my offsets, as obviously the music-industry uses different offsets for their CDs, too........................................................
In fact, they don't care about that........
Well, I reread the satcp article, and came to the conclusion:
hmm, I could make EAC-offset CDs, 3 ones, each with a slightly different offset, adjusted by my Plex.
Measuring the resulting offsets of my Plex and my Tosh with these 3 CDs should result to a clear result.
So I did.
1. CD: burned by write Plex offset in EAC: 0
2. CD: burned by write Plex offset in EAC: +30
3. CD: burned by write Plex offset in EAC: -30 (correct according to Plextools and satcp)
Results of read offset corrections for the Plex:
1. CD: +325 (remark: 355 - 30 = 325)
2. CD: +295 (remark: 355 - 30 - 30 = 295)
3. CD: +355 (remark: of course the correct value, given by Plextools and by table at satcp !
So, 3. CD is the "true" EAC-offset-test-CD, but the other 2 CDs will give confirmation, which is needed by this indirect measurements.
You see, how i used the Plex as known basis.
Results of read offset corrections for the Toshiba:
1. CD: -502 (remark: -472 - 30 = -502)
2. CD: -532 (remark: -472 - 30 - 30 = -532)
3. CD: -472 (remark: of course the correct value, measured by "correct" EAC-offset-test-CD.
Additionally this value of -472 is given in table at satcp for the newer Toshiba models ! (which is of course only a "weak" confirmation, lol).
All single measurements were carried out 3 times.
Interestingly the offset-correction for the older model T. SD-M 1212 is +116, but no Firmware (FW) specified at satcp.
But the offset-corrections for the newer models SD-M 1402, 1501 and 1602 are given with -472, and the FW has an according naming scheme to my Toshiba SD-M 1222, i.e. 1004, 1008
Yes, finally, the drive features like audio-cashing, c2 etc, are the same like by my model.
So, here is the final result,
read offset correction for EAC:
-472
for Toshiba DVD/CD-Rom SD-M 1222, Firmware 1004
Further prove, that offsets for my Plex and my Toshiba are correct:
I extracted 3 songs out of a CD, each by Plex and by Toshiba.
each test & copy, and secure mode, of course.
The resulting crc checksums were the same, independent, which drive extracted the waves.
A compare by content showed, "files are identical !", of course,
using Windows Commander 32 (similar to Total Commander).
No use of null samples (EAC options) was disabled, for this test.
Well, I send the formular to satcp, too,
so that the Toshiba 1222 is described/written in that database, too.
Well, finally I stand by my opinion, that offsets are one the least important issues:
The music industry doesn't care at all.
Example :
Queen - Greatest Hits:
I have a original pressing, which differs about 800 samples from the pressing given as reference-CD.
Taken from satcp:
** Now before you start to panic you should know that 30, 325 and 355 samples are very short times. To get an idea about the real length in time of a sample use following formula:
time = samples / 44,100
Thus 355 samples is 0.00805 seconds, or 8.05 milliseconds, 325 samples is 0.00737 seconds or 7.37 milliseconds and 30 samples is 0.00068 seconds or 0.68 milliseconds. The offset is a time shift of the data and thus it does not affect the audio quality in any way! Since all tracks on a CD end with silence or fade in each other there's no way you can hear the offset. Therefore the whole offset issue may be ignored if you don't care about that...
Anyway, for us perfectionists there must be a way to correct this issue. **
User's opinion:
Sorry,
it is useless (especially for beginners with EAC) to hassle around with offset correction.
Especially, if you encode by lossy codecs...
Well, it is a nice to have, but we perfectionists should avoid to distract / discourage newbies (new to DAE) by offsets.