Disc Quality tests
Having recorded the maximum amount possible onto the Plextor 16x DVD-R media at its rated recording speed of 16x to all available review drives under default settings with Nero CD-DVD Speed, the next stage of this review will concentrate on potential Disc Quality.
The first part of the Quality tests involved scanning all the pieces of Plextor 16x DVD-R media recorded on each review recording device with the Plextor PX-760A Premium using Plextools XL Q-Check tests to find out how many potential SUM8 (PI Errors) and Sum1 (PI Failures) a playback device would have to correct whilst playing or transferring the recorded media. This also enabled me to obtain which of the 5 recorded pieces of media most matched the average result. The average disc shown below was then subjected to a Beta and Jitter test. Ok its not rocket science and although more tests are available with Plex Tools XL then I have used here, I believe I am showing the most common factors in overall potential disc quality.
"As the whole purpose of reviewing media for our readers is to try and obtain a good idea of the average quality of a given media, I have come up with this new methodoligy for determing these factors. These are my own personal views and by no means as accurate as an Industry CATS device for measuring the quality of a disc but I believe I have come as close as I possibly can do with the equipment available to the average user."
I will expect that not every piece of media is capable of producing this
with such influences as excepted media/ hardware tolerance levels having an impact but I will expect the results not to consistently stray too far from set standards for a recommended media. It is also the sum of all tests that I use to determine the overall quality of the media and not one test alone.
Results of the 18x over speed on the Plextor PX-760A Premium under firmware revision 1.01 are available Here for comparison.
The less Sum1 and Sum8 that are found on a media then in theory the better the chances are of good long term playback for this media without data loss becoming a significant problem. Thats not to say that recordings with high Sum1 and Sum8 levels will be bad - the error correction logic of DVD playback and transfer devices are capable of correcting many potential errors. There is just more chance they might be affected by such influences as dirt or fingerprints. Different scanning devices scan slightly differently but basic guidelines using a Plextor drive are that Sum8 should not exceed 280 for sustained periods and Sum1 should not exceed 4 for sustained periods. You don't want to see any reported POF's (Parity Outer Failures) as these normally should result in uncorrectable errors!
Results of the 18x over speed on the Plextor PX-760A Premium under firmware revision 1.01 are available Here for comparison.
Jitter and beta must remain within set specifications for a Plextor scan (Beta should not exceed +15 or -5 for sustained periods with the more level the result the better). Jitter should stay within the lower half of the graph for best results. Reading devices with good jitter correction ability should be able to read higher reported levels better than those that don't.
Results of the 18x over speed on the Plextor PX-760A Premium under firmware revision 1.01 are available Here for comparison.
Overview of Disc Quality tests:
Regardless of review recording device used at its rated speed of 16x the average results of each recording device achieved with the Plextor 16x DVD-R media is to be considered very pleasing. Potential errors are to be considered very low and well within set specifications for good playback or transfer of data. At an over speed of 18x on the Plextor PX-760A Premium, potential errors are higher in total and more concentrated towards the outer edge of the recording but still very acceptable indeed and to be considered of good quality.
"Please note that you will need a compatible drive for doing these scans such as the Plextor PX-760A PremiumI have used in this review for making my decisions on the potential quality of this media. Other drives you could try include BenQ, Liteon, NU TECH and ASUS branded writers, but only the Plextor drives with Q check functions offer the full range of tests."
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