Error Correction Tests

In the following tests we check the drive's behavior when reading scratched / defective audio discs. The test discs used were the ABEX series from ALMEDIO.

- ABEX TCD-721R

Errors total	Num: 126635939
Errors (Loudness) dB(A)	Num: 592873	Avg: -38.2 dB(A)	Max: -4.8 dB(A)
Error Muting Samples	Num: 23162	Avg: 3338.1 Samples	Max: 3584 Samples
Skips Samples	Num: 18	Avg: 1314.9 Samples	Max: 2939 Samples
Total Test Result	45.2 points (out of 100.0 maximum)

The performance here is anything but good. The total error count is extremely high, as are the average and maximum loudness error level at -38.2dB and -4.8dB respectively. The skipped samples are also high and the final score of 45.2 is a good indication of just how badly the drive performed. Please note that the drive was very slow in the ripping process of the test disc. This indicates a general strategy of the Sony DRU-530A, to lower the reading speed when the condition of the disc is bad. Although this strategy could be legitimate in some cases offering accurate results, it turns out to be ineffective with heavily scratched discs.

- ABEX TCD-726

Errors total	Num: 11145
Errors (Loudness) dB(A)	Num: 48	Avg: -38.2 dB(A)	Max: -23.3 dB(A)
Error Muting Samples	Num: 26	Avg: 1.0 Samples	Max: 0 Samples
Skips Samples	Num: 0	Avg: 0 Samples	Max: 0 Samples
Total Test Result	89.2 points (out of 100.0 maximum)

The Abex TCD-726 test disc is much easier for drives in general to read. While the SONY DRU-530A managed to do better this time, the score which is a good one, isn't as good as we have seen from most drives where 100.0 is the norm, especially for a good drive. Strangely enough, the results for these two ABEX disc tests for the Optorite drive yielded almost identical behavior and scores. The explanation for was mentioned in the previous test. The drive is able to accurately read scratched media, as far as the the size of the scratch is lower than 1.500mm approximately.

- CD-Check Audio Test Disc

The CD-Check Test Disc is a very useful tool for evaluating the Sound Reproduction / Error correction capabilities of a CD player. The disc offers a signal combination with disc error patterns to rate the drive's abilities to read music and reproduce it completely. Five tracks on the disc contain a sequence of progressively more difficult tests. These tracks are referred to as Check Level-1 through Check Level-5.

The tracks are reproduced (played) through a software multimedia player (i.e. Windows Media Player). Each level is considered as passed, if the tone coming out from the speakers is smooth, continuous without interruptions, skipping or looping. The higher the Check Level passed, the more reliable the sound reproduction of the tested drive.

Error Level	1	2	3	4	5
SONY DRU-530A	5/5	5/5	5/5	5/5	5/5

The drive successfully passed all of the 5 check levels for this test. Notice that the 5th check level has a scratch a size of 1.500 mm, and it is difficult to be read with most drives. Hence, we can say that the drive is exceptionally good at correcting this type of defective disc.

- Summary

Test Disc	Reading Speed	Score
ABEX TCD-721R	Max	45.2
ABEX TCD-726		89.2
Average Score		67.2

So, summarizing we can say that the drive is very good at correcting badly scratched discs, since it has been one of very few drives to read all five check levels with the CD audio test disc. Nonetheless, the ABEX test results weren't good and it will be interesting to see how the drive performs in the remainder of our test. Up to now, the SONY and Optorite drives have performed as though they were one and the same drive. It will be interesting to see if this will carry through to the remainder of our test suite.