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

The performance with this disc is not the best. The total error count was extremely high, as was the maximum loudness error level at -18.4dB and the number of skipped samples. The final score of 65.0 is rather low and is indicativee of the poor performance of the drive.

- ABEX TCD-726

The Abex TCD-726 test disc is much easier for drives in general to read. The NEC ND-2500A managed to do better this time, but the score of 81.2 is low, especially when most drives score somewhere in the 90's and the better drives close to 100.

- 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.

The drive successfully passed only the first two out of the five check levels for this test. Once again the drive had poor performance. While it is accepted that the 5th level is difficult to read with almost all but the very best of drives, most drives will pass the third level and a good drive the 4th.

- Summary

The NEC ND-2500A managed an average score of 73.1 out of 100. This is a very low score and poses some doubts as to the abilities of the drive to read and correct defective discs.