i have an old HP CD writer 8200, which is a re-badged sony drive i believe. i was eager to find out the correct offsets. i just checked out satcp's website and found that 2 people reported this drive (the re-badged sony model, not HP) had a read offset of 1160 and write offset of -6.

when i ripped and burned a CD with this drive (with all offsets set to zero) and compared it in EAC, i got 1154 extra samples, which is the combined read and write offset. so, naturally, i assume that the numbers on satcp's website were correct.

however, when i ripped and wrote a CD with these settings and compared with EAC, i was showing 6 missing samples (and the error correction indicator in EAC was going nuts when i was ripping the CD-R). so, i changed the read offset to 1154 and left the write offset at zero. i ripped a CD and burned it to CD-R and then compared with EAC with these settings. this time, no errors were reported. there were no extra or missing samples.

therefore, is it possible for drive not have a write offset at all? if so, could it be possible that even though HP uses re-badged sony drives that some alterations are made by HP (since the sony drive appears to be producing different results)? or, perhaps, the write offset is too small (6 samples) and is being ignored by EAC?

Once the combined offset is OK, your copies have zero offset from your originals.

that's what i was told -- that one can make exact copies using the combined offsets, but that it's still preferred to know the seperate offsets. ah well... if EAC reports no missing or extra samples i guess it's ok. still, i believe this explores the possibility that companies who use re-badged drives may make certain alterations to the unit and as such the settings of the re-badged drive may not always be the same for the original drive.

I have a "HP - CD-Writer+ 8200a"
That has a read offset of +572 and write offset -6.
Isn't that the drive you have?

Of course they make alterations to the drive, specially on its firmware.
Why do you think the drive is identified as a different brand and model?
I don't think this impacts the offsets, though.
But you need not to worry about them, IMHO.

it's an external USB drive. HP 8210e

No, anyone using a wrong reference will still get the right combined offset, but with wrong separate offsets. Examples:
+1160 and -6 = +1154
+1154 and 0 = +1154
+577 and -577 = +1154
etc



There is no need for this hypothesis. The 6 missing samples come from the write offset correction, that lost the samples because it didn't overwrite into lead-in.



EAC only supports overwriting with some Teac drives. Overwriting is disabled for any other brand. Not sure if it works with all drives. Search the EAC forum and EAC yahoogroups about this.


Knowing the separate offsets is useful when you trade with someone else using separate offsets, or if you can overwrite into lead in/out with a Teac drive.

When using the combined offsets, you make a perfect copy for YOUR drive only. (or a drive with the same offsets)
When using separate offsets, you make a perfect copy for EVERY drive.

This is oversimplification though, because without reading the Lead-in and Lead-out, there are still situations where you will not produce a perfect copy.


Are you sure about this? I have used the feature with Lite-On and Plextor drives as well.

External drives are usually just internal drives in a case. Try to find out what drive is inside. The offsets for that should be the same all over.

To underscore Pio2001's and mmortal's point - there are situations where you'd want to use the separate offsets. If you're ripping a disc to create shn or flac to share electronically, a la etree.org, you would want to make only the read offset adjustment. Similarly, the person on the other end would want to use only the write offset adjustment to burn it as audio to CDR.

Though I'd agree, offsets are perhaps the least important issue, especially given their complexity. Far more important is using the right settings in EAC.

Yes, you can enable it, but EAC doesn't overwrite anything. Just test. Cut the middle of a song (no silence), set the opposite of the combined offset as write offset, and zero as read offset, burn it and rip it. If your drive overwrites, the result must be identical to the original, otherwise, you'll get silent samples instead (same amount as your combined offset).



It is even more complicated. In both cases, the offset of the copy is perfect. Using the combined offset only prevents to properly overread/write.
In some cases, the use of combined offset is even more accurate than the use of separate offsets, because if your drive can't overread, and the combined offset in inferior to the read offset (same signum, inferior absolute value), you crop less data with it.

this actually happened to one of the tracks in the middle of the CD. it was a copy of a classical CD where one movement is split into two tracks. i should also add that i did not burn this CD-R with EAC. i used CD Architect, which doesn't have the option of correcting a write offset. therefore, no write offset correction was applied. only a read offset of +1160 was used. i obtained this figure from satcp's database. one thing is for certain: when all offsets are set to zero in EAC, the CD-R copy is reported to have 1154 repeated samples, which is quite different from the figures Jan S posted considering he has virtually the same drive.

how can i find out for sure? from all the infomation i gathered online it appears to be a sony drive. i tried getting more details from HP tech support but these people don't have any information about this drive. one chapette over there told me she doesn't even know what offsets are.

that's exactly what i want to do. i share stuff occassionally on usenet, especially the lossless audio groups.

just for reference sakes i would really like to know the precise read and write offsets, and then just switch between them in EAC, depending on the situation.

Well, in the case the copy is offsetted from the original by 6 samples, since your writer has a -6 write offset, and you get 6 missing samples in the compare wavs.

Offsetted wavs are reported as having "missing samples" or "repeated samples".



In this case, ask someone from your trading group who knows his real offsets to burn an EAC reference CD and send it to you. Some people on the EAC yahoogroups can certainly do it for you too, under the condition that in turn, you do it for one or two other people who would ask you.

Two ideas come to mind:

- Google sees all and knows all, or
- A screwdriver

Unless someone knows a site with a table of such info

ahhh i see. because i didn't use EAC to write to the CD-r copy... ahhh... ok, i got it now


i tried google. couldn't find anything besides what i already know. if i use a screwdriver chances are this drive won't work again