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EAC: how important is the read sample offset correction value?

Hi everyone.

I’m ripping my collection to flac with eac, secure mode, using test and copy and accuraterip. Quality is my priority. I don’t understand how important is the read sample offset correction value. Can you please explain me in simple words? I read the guide of course but still I didn’t understand. I’m not an expert and I’m not a native English speaker.

I calculated my offset correction value and it is +6. It means that with my drive (a new one, but kinda cheap) is bad? How is it compared to a drive with a value of, for example, +667? The higher the value the better would be my rip? I noticed that recent cd drives tend to have a lower value compared to older ones... that means that the quality is inferior?

It would be a good idea to look for a better drive? Maybe a faster one (mine is quite slow) with an higher read offset correction value and a more bulky construction? Please give me some advice, especially about this value thing that I really don’t understand. Thanks to everybody!

Re: EAC: how important is the read sample offset correction value?

Reply #1
The quality of your drive is probably fine.  A crappy drive will throw out errors on just about everything regardless of the CD condition and may even struggle to play a factory pressed CD that's in excellent condition.  A crappy drive will also not last as long.  Doesn't if it's a newer model or an older model.  If it's crap you will know it sooner or later.

A smaller read offset can be better if a drive doesn't support over-reading but not necessary so either.  It's not a proper way to determine overall drive quality by just read offset alone while forgetting about the drive's ability to over read when this is corrected.  Read offset is important in configuring correctly so that a different drive returns samples in the same exact spot, rather than being shifted forwards or backwards.  It won't affect audio quality but it does affect the ability to compare rips with one another.

You should be checking if the drive has the left/right channel swap bug (recommended that you return any drive that has this issue for a different model) and if you got accurate stream as a supported feature (not the end of the world if you don't have it, newer drives are almost always likely to have it).

If things are slow than it's probably because your drive caches audio (newer drives are more likely to do this).  In EAC this will result in a speed penalty.  Your drive won't last as long if this is case as EAC will wear it out much faster.

Re: EAC: how important is the read sample offset correction value?

Reply #2
Hi,

Thanks for your answer. The drive is this one: https://www.asus.com/us/Optical-Drives-Storage/SDRW08D2SU/

In detecting overreading capability and sample offset (choosing a cd that is recognized) it says:

Overread: none
Sample offset: +682 (but when I check "use accurate rip" it is greyed and says +6 what does this mean?!)

The drive features accurate stream and there is no problem with right/left swap. I tried to listen to a song ripped in flac from a cd and the same song in Tidal with my portable device and headphones and there was no difference. Anyway still I don't understand this offset correction value issue... so it's better to have a low value (like +6)? Or there is no difference since my drive says overread: none? Please let me know. Thanks.

Re: EAC: how important is the read sample offset correction value?

Reply #3
That model drive is purged from the Accuraterip database: http://www.accuraterip.com/driveoffsets.htm

What that means is the offset is not consistent between different manufacturing batches or firmware.  What you can do is if you have 3 different key discs that's in the Accuraterip database is use that and have it detect the true offset.  You'll need 3 of those before you can use Accuraterip with that drive.  If this is too much hassle you can get or use a different drive.

+682 with no over-read is worse than +6 with no over-read.  +682 with over-read (lead-out) is better than +6 with no over-read, where +682 with over-read (lead in) is worse than +6 with no over-read.  For positive values (+) you want the ability to over-read the lead out, where with negative values (-) you want the ability to over-read the lead-in.  Smaller values have less of an impact than larger ones if your drive doesn't support over-read at all or doesn't support the correct one that you need.

If you check "use Accuraterip with this drive", it will gray out the offset box and show what Accuraterip is configured to use.  If you uncheck it, any previously entered value that you used manually will typically show up.

Re: EAC: how important is the read sample offset correction value?

Reply #4
That model drive is purged from the Accuraterip database: http://www.accuraterip.com/driveoffsets.htm

What that means is the offset is not consistent between different manufacturing batches or firmware.  What you can do is if you have 3 different key discs that's in the Accuraterip database is use that and have it detect the true offset.  You'll need 3 of those before you can use Accuraterip with that drive.  If this is too much hassle you can get or use a different drive.

+682 with no over-read is worse than +6 with no over-read.  +682 with over-read (lead-out) is better than +6 with no over-read, where +682 with over-read (lead in) is worse than +6 with no over-read.  For positive values (+) you want the ability to over-read the lead out, where with negative values (-) you want the ability to over-read the lead-in.  Smaller values have less of an impact than larger ones if your drive doesn't support over-read at all or doesn't support the correct one that you need.

If you check "use Accuraterip with this drive", it will gray out the offset box and show what Accuraterip is configured to use.  If you uncheck it, any previously entered value that you used manually will typically show up.

Thanks! I think I get it. I have three cds that can be used to configure accuraterip (after all, there are so so many now). Would you recommend to look for a better drive? I can use only external drives with usb connection. My only concern is that I could spend 100 euros or more for a new one, those who usually read/write blu rays and so on just to discover that they don’t do a better job with eac... I would like something in the 30-40 euros range, easy to find new, nothing fancy but a little better than this one. Mine does a good job ripping, a brand new cd or a near mint one is usually ripped with almost every track quality of 100% and some with 99.9%. Never detected any error except for a poor quality bootleg cd.

Re: EAC: how important is the read sample offset correction value?

Reply #5
By the way the accuraterip list of cd drive offset has no information about the capability of overreading in lead in or lead out so it’s not useful when thinking about a new drive to buy...

Re: EAC: how important is the read sample offset correction value?

Reply #6
If you had a drive with a +6 offset and no over-read abilities, you would find there are not actually many CDs where there is audio data in the last 6 samples any how (they are almost always pure digital silence), and if there were audio data it would be effectively silence anyhow. Those CDs with actual audio data right to the lead out are poorly mastered (potentially would cause a click with speakers).

Re: EAC: how important is the read sample offset correction value?

Reply #7
The problem is that I’m not even sure if the offset is +6. When I go to option - offset / speed and I detect read sample offset correction the value is +682 (I have only one cd that is in the eac short list, and it is old and not in great conditions). Then I chose apply and this value is shown in the superior half of the window, but when I check “use accuraterip” that superior part is greyed and the number changes from +682 to +6. What does this mean? When a cd is not recognized by accuraterip (I have many of them, usually underground stuff) the offset would be of +6 or +682?

Re: EAC: how important is the read sample offset correction value?

Reply #8
You say you calculated it to be +682. I think we need to know more about that processes. The standard way of determining the read offset relative to the commonly accepted reference is not done through calculation.

Without a compelling and detailed answer to that and knowing the number in EAC’s settings is +6 and grayed-out then I don’t see why the 682 figure should be given any weight.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Re: EAC: how important is the read sample offset correction value?

Reply #9
You say you calculated it to be +682. I think we need to know more about that processes. The standard way of determining the read offset relative to the commonly accepted reference is not done through calculation.

Without a compelling and detailed answer to that and knowing the number in EAC’s settings is +6 and grayed-out then I don’t see why the 682 figure should be given any weight.

Thanks for the answer. Anyway it would be great to know if there is any external device that can overread and it doens’t require cache flushing... I see that the most accurate drives are actually quite old and internal. Any experience of a recent doing a very very good job?


Re: EAC: how important is the read sample offset correction value?

Reply #11
Ripping accuracy trumps ripping features. With a good drive you’ll probably be able to get away with ripping in burst mode and verifying/correcting with CUE Tools in the majority of situations. Secure ripping might only help with edge cases. Discs not in the database should be treated differently. Spoon maintains a list of the of drive performance based on accuracy.


With CUE Tools, the offset correction feature is far less relevant, if at all.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Re: EAC: how important is the read sample offset correction value?

Reply #12
Ripping accuracy trumps ripping features. With a good drive you’ll probably be able to get away with ripping in burst mode and verifying/correcting with CUE Tools in the majority of situations. Secure ripping might only help with edge cases. Discs not in the database should be treated differently. Spoon maintains a list of the of drive performance based on accuracy.


With CUE Tools, the offset correction feature is far less relevant, if at all.

So your advice is to look for a better drive? But are there drives that can I can buy new that are known to work fine with eac? Is there a way to see this list? I’ve seen a list on the dbpoweramp forum but the best drives are very old and allways internal. I read that this one is quite good (and cheap, and easy to find):

https://www.amazon.it/Liteon-IHAS124-14-Masterizzatore-DVD-RW-Nero/dp/B00ERJXTE4

But it is an internal drive and I honestly don’t know how to make an internal drive external... I know I would need an enclosure but I never did anything like that. Another option would be to buy a modern, quite expensive external drive but I have no idea about his features regarding eac...

Re: EAC: how important is the read sample offset correction value?

Reply #13
I'm merely suggesting not to bother yourself with offsets or ripping using a secure mode unless you find a title that can't be either verified or corrected using CUETools.
Is 24-bit/192kHz good enough for your lo-fi vinyl, or do you need 32/384?

Re: EAC: how important is the read sample offset correction value?

Reply #14
I honestly don’t know how to make an internal drive external...
Meaning, you only have a laptop?
High Voltage socket-nose-avatar


 

 
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