This series of tests checks the drive's ability to correct/conceal possible erroneous data after reading artificially scratched / defective audio discs. The test discs used were the ABEX series from ALMEDIO.

Specifically, a software compares two audio files using FFT analysis. The first audio file has been extracted by a normal audio disc. The second one is the result of the extraction of the another disc which hold the same audio track, but it also has specific defects on its surface. The similarity factor of the the two tracks unveils the error correction capabilities of the drive.

The differences between the two compared tracks are translated to a signal (noise) illustrated in the following graphs.

- ABEX TCD-721R

In the graph above, one can note that the drive's performance was average. As soon as we move to the defected data area many errors were reported. In addition, error hiding mechanisms of the drive failed to keep the errors under the -60 db barrier, which is considered as the limit that when exceeded, problems in audio playback may be reported.

- ABEX TCD-726

The second test disc was easier to overcome. The drive responded flawlessly and successfully corrected all read errors.

- CD-Check Audio Test Disc

The CD-Check Test Disc is another 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 (e.g. 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.

A good performance for the DX 401S drive here, successfully playing the first 4 tracks.