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 overall performance with the specific disc for the ND-4551A has been improved in comparison to the previous ND-3540A. The drive has good performance here but it could still be better. The total error count is high but fortunately, the maximum error loudness is at acceptable limits and this time, no samples were skipped.

- ABEX TCD-726

The 726 test media does not present any problems with the majority of the tested drives. In the case of our ND-4551A, the performance was not perfect as we are used to with most drives and there were some errors reported.

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

With this test disc, the drive reported better than average performance, achieving flawless reading with 4 out of 5 tracks.

- Summary

Performance with the 721 test disc was good but we had hoped for better results with the 726 test disc. Certainly the CD-Check Audio Test Disc results place it in a category with the better drives and overall, the NEC drive is a device with better than average CD error correction capabilities.