Hi,

I just bought a Plextor PX-130a for DAE.

But I'm not surte which gap detection mode to use ;

For example, a screenshot with Detection Mode A ; Secure (Same result with LG GSA-4167b in Secure Mode A):



This looks a bit srange, doesn't it?

If I switch to Mode B, I get different results:



Looks like Mode B is better, what do you think?

I've been ripping about 40 CDs now with Mode A Settings with my LG Drive (Gaps are equal with Plextor Mode A).

So if B is generally the right one now, I have to rerip all my CDs...

Isn't there another way of getting a proof?

Track CRCs are equal of original and copy (by eac with cue sheet).

I hope someone can help me...

When you play this disc in a regular CD player, does every track show a gap?

IOW, during the transition between tracks does the displayed time show a negative sign?

Yes, just tried it in my car cd player, there is a short gap at most tracks, and track 13 pregap is longer. So Method A seems to be valid, doesn't it?

When I rip a whole CD to WAV, create a non compliant cuesheet and burn this cuesheet afterwards with EAC (with correct read & write offsets of course), and CRC of every track is teh same as on the original cd, can you guarant a perfect rip? Or don't the gaps influence the CRC?

Thanks

Detecting where a gap starts (a 00 index) is not the same as whether you hear a gap or not. Whether or not you detect them and whether or not the detection is correct, they will be included in the extraction by default, unless you've changed the default setting to leave them out.

The location of gaps do not influence the CRC so long as you leave EAC in the default setting of appending gaps to the previous track or if you rip the disc as a single-file image.

The answer to your question of which is right lies in the question that I asked you:
That is to say when you play the disc back in a standard CD player.

Okay thanks so far. So I'll keep on ripping in Detection Mode A as I did before.



EDIT:

One more question: Do different -Read Offsets- influence CRCs?

I honestly can't tell you which version is correct. Do you have EAC's gap detection set to secure in both cases?

Depends on whether you use null samples for CRC calculations, but in general (meaning sometimes even when not including null samples in CRC calculations), YES.

Yes, Gap Detection is in both cases switched to Secure.

Well that's disheartening since clearly at least one of the methods is giving erroneous results.

IMO and for my own uses, detecting where gaps start isn't important and this really isn't anything to worry about.

He's using cuesheets and so probably desires accurate reading of gaps.

I can't see how two different methods would provide different results. You'll probably have me going and checking all of my rips now! Have you tried method C?

I don't know how else the methods could be checked, besides somehow obtaining another cuesheet of a CD that you have and comparing it with a rip of your own.

Method C is very interesting but absolutely unusable (EAC does this with EVERY audio CD):





Sorry for confusing you .. I think I've found out that gap method A is the right one to use.

Well, I don't know what to suggest. All I can tell you is that you'll have me rushing away to check my drive's reaction to the different settings now!

For the moment, I'd probably say that Mode A's timings look suspect, as the gaps are so short. So, in a pinch, I'd use B!

But in my hardware audio player I can see gaps between tracks for a very short time by negative time..

I'm just as confused as ever again. Perhaps you are right, but I still can't explain the differences between the two modes.

Go with what feels right to you! </lifecoach>

I'm just trying out something..

MODE A:

I detected gaps of an original CD. Then burnt this cuesheet to CD-R and detected gaps of this CD again. My Plextor reads exactly the same gaps on original cd as on copy cd-r. This means, that it correctly reads the gaps of my burnt cd-r, because I know which gaps they must have.

Now mode b.

Detected Gaps of original CD, created cuesheet and ripped the cd:



Then i burnt this cuesheet too. But as i wanted to detect the gaps of this copy in mode b again, it was suddenly different:



So it's 100% sure that mode B is not working correctly.

I hope you could follow me.

EDIT: It's a proof, isn't it?

>It's a proof, isn't it?

I'd say so, yes. Good idea!

Hi Be Positive

Thank you very much for investigating this issue. I was starting to get very affraid when i began to read your first posts since i also have an LG GSA-4167B, and since it also could mean that the cuesheets i have made with this drive could have inaccurate timings for the pause areas, but luckilly i have also used mode A - Secure, so i'm allright

(When i got the drive and tested the different gap detection modes, then they all gave identical results on the CDs that i tested it with, but as mode A was fastest, then i choose that...)

Thank's again, mate

CU, Martin.

Edit: Typo.

So, if I wanted to test the accuracy of my gap detection method, should I do what Be Positive did and just burn a new CD and compare gaps?

I think it depends on the circumstances.

Be Positive was certainly able to prove that method B was not correct using two different methods. He was also able to demonstrate that method A has been able to deliver consistent results via burning a CD and that all the tracks did in fact have gaps according to his CD player.

As with most things, it's much easier to cite examples to disprove something rather than prove something.

The question still remains, if the copy indeed has the same gap behavior as the original, why then does method B give different results between the two? It could be that method B doesn't give consistent results just from using the original disc. This is important to know, but it wasn't mentioned.

Provided that you're ripping tracks in accordance with the standard of appending gaps to the previous track, gaps only affect playback on a standard CD player. If you're not programming a different sequence (or using shuffle?), the only thing that gaps do is indicate a countdown to the next track on the player's display; they do not affect the audio. OTOH, when programming a player, the area marked off by a 00 index will be left out.

When dealing with digital audio players or playback on a computer and you're ripping tracks using the standard method, 00 indices are meaningless, except for HTOA, but HTOA doesn't require the same type of detection as 00 indices that fall between tracks.

FWIW, I also have the same version of Legalize It.

Here are the gaps that I have detected for it:

TRACK 02 Pregap: 00:01:45
TRACK 03 Pregap: 00:01:33
TRACK 04 Pregap: 00:01:25
TRACK 05 Pregap: 00:01:20
TRACK 06 Pregap: 00:00:60
TRACK 07 Pregap: 00:01:20
TRACK 08 Pregap: 00:00:63
TRACK 09 Pregap: 00:01:00
TRACK 10 Pregap: 00:01:18

My results are exactly the same.

I've got the 1999 Reissue.

Thank you

I'm sorry to bump this thread, but it seems the best place for my question/concern.

Having reinstalled my computer, I have of course had to reinstall and set up EAC. It seems to default to method B, which is deemed inaccurate here. I always used method A before and will probably be defaulting to that again. However, my main question is: is it the "most accurate"?

Be Positive, I seem to recall you saying before that you performed gap detection tests with some other applications; did EAC's results using method A match their own?

It's the kind of little thing that annoys me and I'd like to have as accurate results as possible with my drive (a Lite-On LTR-52327S, configure with the new -24 offset). Personally, I feel that Andre should, along with a few other features which will hopefully make it into the next version, at least default "method A Accurate", if not make it the sole option.

All replies are welcome - thanks!

For this particular drive and particular disc, yes.

Read this post:
http://www.digital-inn.de/117689-post14.html

In other words, yes?

I do feel sorry for Andre, having to try to make the most of such a loose standard.