Error Correction Tests

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

- ABEX TCD-721R

Errors total	Num: 943423
Errors (Loudness) dB(A)	Num: 49504	Avg: -73.6 dB(A)	Max: -20.8 dB(A)
Error Muting Samples	Num: 3061	Avg: 1.0 Samples	Max: 11 Samples
Skips Samples	Num: 0	Avg: 0 Samples	Max: 0 Samples
Total Test Result	76.8 points (out of 100.0 maximum)

The drive performed very well with the ABEX TCD-721R test disc, giving a very low count on the number of errors at an average of -73.6 dB. Muting error count was minimal and no samples were skipped. The total score of 76.8 is quite good.

- ABEX TCD-726

Errors total	Num: 0
Errors (Loudness) dB(A)	Num:18	Avg: -174.0 dB(A)	Max: -174.0 dB(A)
Error Muting Samples	Num: 0	Avg: 0.0 Samples	Max: 0 Samples
Skips Samples	Num: 0	Avg: 0 Samples	Max: 0 Samples
Total Test Result	100.0 points (out of 100.0 maximum)

The Abex TCD-726 test disc is much easier for drives in general to read, and as such, the LiteOn LDW-811S drive corrected almost all errors with a high overall quality score of 100 points. In fact, the loudness error returned had an average of -174.0 dB which doesn't even register on the graph.

- 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
LiteOn LDW-811S	5/5	5/5	5/5	0/5	0/5

The drive succesfully passed the first 3 check levels for this test. Playing the 4th and 5th tracks produced a constant noise in the background. Since we are testing the analogue audio output, we could conclude here that the drive is capable of "correcting" errors created by scratches with size less than the 1.125 mm present on the 4th check level. It is a little surprising however, that the LiteOn drive did not pass the 4th check level considering the good results returned in the tests with the ABEX TCD discs previously. The 5th check level, which has a scratch a size of 1.500 mm, is difficult to read with most drives.

- Summary

Test Disc	Reading Speed	Score
ABEX TCD-721R	Max	76.8
ABEX TCD-726		100.0
Average Score		88.4

Combining the two scores from the ABEX tests gives an average total score of 88.4 points out of 100. This is a very good overall score, however the only dissapointment was the drive's inability to read at least the 4th check level on the audio test disc.