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

As can be seen from the graph above, the drive had a bit of difficulty with the ABEX TCD-721R test disc. The maximum of -8.7 dB(A) for loudness errors is a little high, as is the number of errors at 57779. Muting sample errors also returned a high count, but the skipped samples count is significant and shows the drive is not capable of correcting badly damaged discs.

Also, from the above table, it can be seen that the C2 accuracy for the drive is quite low at only 67%.

The total test result is 63.6 points out of 100 while the C2 accuracy is 67.0%

- ABEX TCD-726

The Abex TCD-726 test disc is much easier for drives in general to read, and as such, the AOpen drive managed a better score with this disc than it did with the 721R test disc previously. Here, in all three cases (i.e. loudness, muting and skipped samples), the results are quite good. The average error loudness was -90.8 dB(A), with 1 sample muted and no samples skipped. C2 accuracy however, was again low.

The total test result is 91.1 points while the C2 accuracy is 66.8%

- 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 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 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.

The drive had problems with this test disc. From as early as the 3d track on the disc, sound reproduction produced audible clicks. The error size on the 3rd track is 0.750mm and the drive only managed to playback the track without interruptions for two out of the five times. It did not manage to playback the 4th and 5th tracks at all.

- Summary

Combining the two scores from the ABEX tests gives an average total score of 77.7 points out of 100. This score is not one of the better scores we have seen from a drive and certainly indicates that there is room for improvement here. What is obvious is that while the drive can probably handle minor defects on a discs surface, it does have problems with anything major.