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KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/5/2003 10:23:16 PM   
Halcyon

 

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I tested three discs with both Kprobe 1.1.14 (on LiteOn 48246S, latest fw) and Plextools Professional 2.05 (on Plextor Premium, fw 1.02).

All discs were tested at 24x (NOT a max read speed).

The results are quite different. Take a look

Disc 1: Much higher c1 max/avg on Plex, no C2 reported on LiteOn






Disc 2: same differences as above








Disc 3: Differences in Average C1, max C1, existence of C2 and distribution of C1 as a function of time. VERY significant differences.






All discs were burned on the same day (Verbatim DataLifePlus SuperAzo 700Mb), totally faultless with no scratches and were taken from the burner to be tested (i.e. almost no handling for the discs, absolutely no smudges, dirt, etc).

Can anybody explain these results for me?

I mean, I was expecting *some* differences, but with at least roughly equal distribution of errors, error averages in the same order of magnitude and c. the same level of max c1/c2 error figures.

These test result differences point towards the conclusion that either:

A) Plextor Premium + PlexTools is not to be trusted
B) LiteOn + KProbe is not to be trusted
C) Both combos are not to be trusted

Am I doing something wrong?

Which drive/software combo should I trust?

If each drive's ability to read very high quality Mitsubishi chemical media rated for 48x (burned at 24x) at the read speed of 24x is so different from the other, then surely we cannot deduce ANYTHING useful about each result beyond the make of the drive on which the results were obtained (?).

If my tests are correct, Plex can't read Mitsubishi Chemicals discs properly and LiteOn can. If this is the case, then how about the rest of the drives in the world (MSI, Asus, TDK, Cendyne, Optorite, Yamaha, Teac, etc. etc.)????

I can accept the limitations of consumer cd-r quality testing, but these results (if correct) are so downright offputting that I'm not sure anything generally useful can be deduced from home-made c1/c2 measurements.

regards,
Halcyon
Post #: 1
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/5/2003 10:46:45 PM   
Dolphinius_Rex


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try comparing the drives doing tests at 8x. Just a though.


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(in reply to Halcyon)
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RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/6/2003 12:44:52 AM   
Halcyon

 

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I did a test with another disc (Fuji 52x made by Fuji Photo Film).

I tested both at 24x and at 4x on both drives.

LiteOn misses the C2 errors completely and gives lower amount of C1 than Plextor.

Here are the results:

Fuji 52x media burned with LiteOn 48246S (with 52246S firmware) at 52x and tested on LiteOn at 24x with Kprobe:



The same disc as above, but tested at 4x:



Same disc, but tested with Plextor at 24x:



Again same disc, with Plex at 4x:



At least now the time based distribution looks roughly equal and the C1 error count is in the same order of magnitude (although 3x as big on Plextor as on LiteOn).

However, what is alarming that Plextor reports c. 230 C2 errors at both 24x and 24x while LiteOn reports none at either speed.

I'm now adding the following suggestions to my earlier conclusions:

- this is not a single media isolated case (both Mitsubishi Chemicals and Fuji Photo Film high quality media are affected)

- this is not a single test speed or high test speed limited case (testing at lowest possible speeds gives similarly differering results).

To me this is pretty alarming.

Should we really trust the C1/C2 measurement data at all with these consumer drives/software?

Hasn't anybody else tested Plextor Premium and LiteOn drives with same discs?

regards,
Halcyon

(in reply to Halcyon)
Post #: 3
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/6/2003 3:32:47 AM   
Dolphinius_Rex


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Part of this may be due to the LiteON 52246S having extremely good error correction abilities...

hrm, both the LiteON 52246S and the Plextor Premium have 100% C2 accuracy according to the articles/reviews on this webpage, and both also have good error correction abilities.... this is indeed a mystery! perhaps rjw can shed his opinion on this one? I think perhaps C't has done some comparisons that may yet proove useful to this discussion


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RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/6/2003 1:33:55 PM   
rjw

 

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First there's a difference in Plextor c2 and Lite On c2.
Lite On c2 is more like Plextors CU. Also there reporting differnt things. This explains the higher error values for the plextor. I will have to search up again what the software really is reporting.
(characters/sectors/blocks)

Now which drive do we trust ?

Well
C1/C2/CU are drive dependant. So disc behaviour in different drives cause different error rates.
Now at lower speeds this extra behaviour isn't allmost there. For this reason the audiodev CATS analyzers meassures at 1x.
About Plextor vs Audiodev CATS analyzer I should post the results over here in a couple of days.(the Ct' article.)
And if your guys are really lucky then I might come up with much more info very soon.

But why did you recommend high speed reading a couple of posts ago for cd docter[?]

High speed measurement can explain the behaviour of the disc you normally can expect on high speed reading with most drives. Now if you know that your drive can read at high speed quite correct. Then you will also know if the disc might be getting problematic when used at these high speeds on normal cd-rom /dvd-rom drives.
Like I said befor you actually need both.






(in reply to Halcyon)
Post #: 5
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/6/2003 4:49:46 PM   
Halcyon

 

Posts: 172
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quote:

rjw: "First there's a difference in Plextor c2 and Lite On c2."
[\quote]

That's possible, even probable. I don't think there's public information available as to how LiteOn/KProbe classify bit-level errors into C1 and C2.

quote:

Well
C1/C2/CU are drive dependant. So disc behaviour in different drives cause different error rates.



Agreed.

quote:

Now at lower speeds this extra behaviour isn't allmost there. For this reason the audiodev CATS analyzers meassures at 1x.



Yes, drive dependence is diminished as optimal read speed (usually 1x) is approached.

quote:

About Plextor vs Audiodev CATS analyzer I should post the results over here in a couple of days.(the Ct' article.)



That would be very nice of you. Also, any additional information as well would be more than welcome as I'm far from being an expert on the issue.

quote:

But why did you recommend high speed reading a couple of posts ago for cd docter



Did I? I usually try to recommend a lower speed as a true measure of what might be a better indication of what the quality of the disc is.

However, if you plan on using the disc to be tested on the same drive on which you test it, then it makes sense to test at a higher speed (even on max speed), because it simulates real life usage situation that the disc/drive combo will have to face in the future.

So, to clarify my stance if I've badly expressed it before:

- slow test speed is usually a better indication of the drive independent media performance (if an indication of anything at all)

- higher test speed is usually a better practical measure of real-life performance for the test drive / test disc combination under scrutiny, because discs are often read at a higher speed on normal usage

quote:


High speed measurement can explain the behaviour of the disc you normally can expect on high speed reading with most drives.



This is where I partially disagree :)

I think my results show (if correct) that not even a slow test read speed is a guarantee of read performance on another (different maker/model) drive.

Results cannot be generalised from the test drive to another drive, regardless of what the test speed is.

If they were generalisable, then LiteOn/Kprobe and Premium/PlexTools results would be at the very minimum in the same order of magnitude or even better, in a statistically insignificant variance levels.

My tests (again, if correct) show that this is not the case.

The higher the test speed, the less there is correlation with test results and actual high speed 'normal usage' read results _on a different drive_.

I think if you want to test drive compatibility at high speed, you need to test it with the drive you want compatibility with OR you need a test drive from the results of which you can generalise over a larger population of other drives (a dedicated testing platform perhaps?)

I don't think either LiteOn/Kprobe or Plextor/PlexTools combo results have been yet shown to be reliable indicators of media read performance (error counts or even read speed) on OTHER DRIVES except the one on which it was tested.

The only test result showing real-life correlation with a calibrated test gear has been the C'T article. That's why I'm really interested in that article and trying to understand if the Plextor or LiteOn results are to be trusted _EVEN ROUGHLY_ (for any other drive model except on which the test was done).

If anybody has both drives, please do some tests also and contribute comparative results here.

Why am I interested in this? Various reasons:

- I will plan on archiving stuff on CD-Rs that I will want to function years from now (yes, I already have stuff from mid-90's that works well when handled/stored properly)

- In the future it is very UNlikely that I will use the same drives to read these media as I burned/tested them with.

- As such, I need a roughly useful measure of burn quality based on which I can select a media/drive combo that I hope to produce READABLE discs for a wide variety of drives in the future too.

So my needs are practical and not merely academic. Yes, I could in theory archive the burner along with the media, but I think this is a little bit impractical.

regards,
Halcyon






(in reply to Halcyon)
Post #: 6
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/6/2003 7:05:14 PM   
john

 

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Halcyon what your tests showed is possibly correct. As rjw also said, and i confirm, all results are correct from each drives, meaning that both KProbe and PlexTools only measure what the hardware gives. As you can see over the various LiteOn/Sanyo drives generations (under the writing quality article), there are huge differences between the C1/C2 errors from each drive. Why there are differences? Because manufacturers try to improve each new drive reading abilities -> lower C1/C2 reported errors.

The Plextor Premium drive does seem to give more c1/c2 errors than any other LiteOn drive. I am sure that Plextor has made some kind of comparison with professional testers and the CT article will possible give more info about this. We made some comparison with the Jitter curve that PlexTools give and from the results you can see that at some cases, the trend is the same and at others doesn't. Its just how each drive behaves with the inserted disc at various speeds and at different cases (CD-R, CD-RW, Pressed media).

I would say that for now, the Plextor Premium results can be widely compared (between users) and make a wide results base, since we have only one Plextor drive that can report such C1/C2 errors. The differences between the various LiteOn models are huge so we cannot have only one drive to compare them.

Just my 2 cents [:I]


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RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/7/2003 10:44:51 AM   
rjw

 

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quote:
But why did you recommend high speed reading a couple of posts ago for cd docter


ARGHH screwed this one up. IT should have stated why did Irecommend high speed reading [?]
Sorry for screwing things up but when I was typing my reaction I was more busy with doing some other things.

The plextor is actually the drive which should be trusted more then the Lite On's. Why [?]

1 - There is no real difference between what premium drives meassure as errors. (Jitter and Beta is a different story)
2 - There is a difference in the reproduction of Lite On's not only between different models but we've seen also differnce between 2 drives of the same model. OUCH no problem if you use comparisions if you can check with an aditional source or if you compare media and allways on the same drive and with the same software .(Now I know kprobe might be better. Still I don't like it that he switched since now the results are less good to be compared to the older stuff.(So Rex could you do a rerun off all the old media with kprobe ?)
3 - Somethiing you really should not trust are the cd-r error test with a Lite On DVD player. These are really incorrect.

(in reply to Halcyon)
Post #: 8
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/7/2003 5:42:11 PM   
Dolphinius_Rex


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eek....rerun all the old tests? ... hehe, well theoretically yes, I could test all the media again with K-Probe, but that would seriously cut into my time, and I wouldn't be able to work on any new reviews for a while then... not to mention I'd have to re-write the old reviews and explain the results

I'll see what I can do, but no promises on this one! [:I]


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Post #: 9
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/8/2003 11:34:15 AM   
rjw

 

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I know and I allready and I am not asking that you do it right away.
Second problem with retesting is what if the media has aged[?] I can think of CMC Media that is now performing even more worse then befor.

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Post #: 10
RE: KProbe vs Plextools Pro (C1/C2 discrepancy) - 7/8/2003 12:47:51 PM   
Dolphinius_Rex


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From: Vancouver, B.C. Canada
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Maybe a supplement then, instead of a complete re-write, that would save me some time writing it, as well as not confuse some people as much!


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