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: 124502328
Errors (Loudness) dB(A)	Num: 582831	Avg: -25.2 dB(A)	Max: -4.8 dB(A)
Error Muting Samples	Num: 22780	Avg: 3336.6 Samples	Max: 3584 Samples
Skips Samples	Num: 22	Avg: 1128.7 Samples	Max: 2939 Samples
Total Test Result	45.1 points (out of 100.0 maximum)

The drive did not manage to correct severe errors present on the ABEX TCD-721R test disc. Both the amount and the level of the reported errors are high, resulting in a low quality score. On the other hand, the drive starts reporting errors in the expected position and not earlier, meaning that the optics and error correction circuitry are tuned to specifications.

The amount of muted samples was also very high. This means that the drive will generally play your old audio discs well, as long as their physical condition is not as bad as the defects present on the Abex 721R test disc. These are the initial impressions regarding the overall performance of the drive and the following, additional tests should help formulate more accurate conclusions.

- ABEX TCD-726

Errors total	Num: 0
Errors (Loudness) dB(A)	Num:18	Avg: -38.8 dB(A)	Max: -33.1 dB(A)
Error Muting Samples	Num: 0	Avg: 0.0 Samples	Max: 0 Samples
Skips Samples	Num: 2	Avg: 30.0 Samples	Max: 30 Samples
Total Test Result	85.3 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 Optorite DD0401 drive corrected almost all errors with a high overall quality score of 85.3 points.

- 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 ability 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
Optorite DD0401	5/5	5/5	5/5	5/5	5/5

The drive passed all 5 Check Levels of the test. The performance reveals very good sound reproduction and error correction. The fifth level includes an error size of 1.500mm, and the drive managed to play the file without audible clicks.

The results with the Abex TCD-721R (max scratch size 3.00mm) and CD-Check test show that Optorite DD0401 is capable of correcting errors comimg from scratches sized up to 1.500mm approximately.

- Summary

Test Disc	Reading Speed	Score
ABEX TCD-721R	Max	45.1
ABEX TCD-726		85.3
Average Score		65.2

Combining the two scores from the ABEX tests gives an average total score of 65.2 points out of 100. This is not the highest score we have experienced from a drive, but it does not fully reflect the true picture of the drive's performance. The Optorite DD0401 managed to read severely scratched discs with a high accuracy, as long as the scratches did not exceed a critical size.