Error Correction Tests

In the following tests we examine the reading error correction capabilities of YAMAHA CRW-F1DX.

- EAC CD-R Test Disc

- Introduction

We used the testing methodology as described in EAC website. The CD-R test disc includes 5 scratches and a black triangle defect. Using EAC's BURST mode, we ripped the test disc with two different files speeds (max & 4X). The attached analyse.exe software used to get the necessary results.

The graph tells a lot about the abilities of the drive. The quality of the optical system (and/or of the error correction capabilities of the firmware) is shown in at which time index the error start. The error hiding qualities are shown when the wedge gets bigger.

The grid of the graph has the following means:

• The X position of a grid line is always a start of a new minute position on the CD (in play time, up to 74 min).
• The Y axis shows the dB(A) value of the error in the extracted file. dB(A) is a weighting/curve that does not look as much at high and very low frequencies as at medium frequencies, using an A-weighting curve.
• The graph shows a range of 6 dB(A) down to -120.0 dB(A). Each line represents 6 dB(A) of volume (6 dB(A) louder means that the sound is double as loud)
• " For the test CD, everything below -60 dB (A) is quite acceptable for error correction. Anything higher than -42 dB (A) is quite critical, and you would hear that in any case. Of course that also depends on the surrounding music/noise. If the rest of the song is absolutely silent, you will probably even hear a -96 dB (A) - only by using 24 bit audio files. If it is hidden in -6 dB music, you will probably not hear -72 dB (A) (or even -66 dB (A) anymore...

- Explanation

After the analyze finishes, we will get a detailed report about the various errors:

- Errors total tells about the total number of wrong stereo samples. This includes areas of wrong samples that may include some correct samples.

- Errors Loudness is the number of FFT analysis done. For that the average and maximum value tells the power difference of the two signals. No acoustic model is used for this calculation, so the audible error may differ from these values.

- Error Muting tells something about error hiding. On bad errors (or bad error hiding techniques), the last error free sample is held for some time until a new valid sample is found. The number of these mutings is given as first result, following the average and maximum sample length of these mutings.

- Skips are occurring when the sync was lost and the drive had to reposition again (and started on a slightly different position). Non-accurate stream devices would loose the sync very often and smaller and bigger skips occur (thus samples are missing or extraneous). The average and maximum values denote the length in samples of such skips.

- Total Score is calculated according to the previous errors. The higher score a drive gets, the better!

- Test Results (4X Reading)

The YAMAHA CRW-F1DX at 4X, starts reporting errors earlier than with full speed (12mins), but the corrected data ,within the black defect, will stay nearly always below -60 dB(A), which is nearly un-audible if it is surrounded by loud music. The 5 scratches are not fully corrected, but stay below -54 dB(A). As the test results showed, the CRW-F1DX gets 79.1 score out of 100 (max).

- Test Results (Max Reading)

The CRW-F1DX, at full speed, starts reporting errors at 16mins. The errors within the black triangle defect, stay below -60 dB(average), but there is also a spike up to -30dB. The 5 scratches are not repaired and the first scratch reaches -12 dB, producing a score of 74.3, out of 100 (max).

- ABEX TCD-721R

- Introduction

This test disc includes artificial scratches with lengths from 1.8 mm to 3.0 mm.

Using the ABEX TCD-714 as the reference disc, we created the reference.wav file that is needed for the comparison. We ripped the disc at full speed, using EAC's copy range and after running the analyse.exe software we got the error graph.

- Test Results (4X speed)

The ABEX TCD-721 causes problems to most of the tested drives, including the YAMAHA CRW-F1DX. The drive reports errors early, at 12mins, but stay below -66 dB. After 20mins, the errors reach -52 dB (average), while many spikes reach up to -10 dB! The drive's overall score is 62.3 out of 100 (max).

- Test Results (Max speed)

At the maximum reading speed, the drive got a better score (70.0) compared to the 4X setting. This can be explained, since the Yamaha CRW-F1 series doesn't support minimum of 4X reading speed, but 10X. The ripping speed in either 4X/Max setting was close, so the results are also close…

- ABEX TCD-726

- Introduction

The ABEX TCD-726 includes three kinds of defects, interruption, black dots and fingerprints are prepared in this disc. The interruption defects are sized from 0.5 mm to 1.0 mm. The black dots are from 0.4 mm to 1.0 mm. Lastly, the fingerprints are from 65 to 75 micro meters.

- Test Results (4X Speed)

At 4X reading speed, the drive showed very good behavior. Only few errors occurred during the 26-28minutes, under -60 dB. The drive gets a high score of 92.4 out of 100 (max).

- Test Results (Max Speed)

At the maximum reading speed, again few errors occurred during the 27-28minutes. This time the drive got a higher score of 92.6 out of 100 (max), since the maximum loudness reached -71.9dB compared to the -59.6dB of the 4X reading speed.

- Conclusion

The Yamaha CRW-F1DX gets an average 78.45 score out of 100 at our reading error correction tests.