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Burn Quality at Different Speeds

AOpen COM5232/AAH

The quality of blanks written at the maximum speed is rather good. The Block Error Rate (BLER) is low, not exceeding 30 errors in peaks. The Burst Error Length (BERL) parameter goes out of the acceptable range at one point only. However, there’s no BLER surge at this point, so this is not a mechanical defect of the medium, but a fault of the drive. There are E12 and E22 errors – not too many, but some other drives make fewer errors or none at all. Jitter fits into the norm, although there are still problems with Land Jitter. The sequences of 3T size are slightly longer than acceptable, and the others fit exactly into the norm. That’s why we have that look of the Pit Histogram – adjacent areas are overlapping up to a sequence of 5T. There’re minor overlaps on the Land Histogram, too, but they don’t affect the quality of the written disc much.

Now, let’s examine the disc burned at 24x speed.

It’s roughly the same here as with the disc burned at 52x. The Land Jitter remained the same, only its level is slightly lower, but there are no overlapping areas on the Land Histogram, although neighboring areas are very close to each other. The C2 error count is still high.

Now, let’s examine the disc rated for 48x, but burned at 52x.

This is not the drive’s normal burn mode, but if it claims it can do it, why not to check it out?

However strange, some parameters have even improved! For example, the BLER and BERL values have reduced, and there are fewer second encoder errors. The Land Jitter has increased, though. It is above the norm for all the sequence lengths, and the disc symmetry on the initial area is distorted. Anyway, considering that that medium wasn’t originally rated for 52x, the drive did its job well enough.

Overall, the quality of the burned media improves as we go down to lower speeds. The drive is good at writing at its maximum speed, and the reduction of speed to 24x brings a slight quality improvement. In contrast to pure CD-RWs and best combo drives, this model looks rather unassuming. Yet, it is good enough against the crowd of ordinary combo devices.

Samsung SM-352N

That’s overall a good result. The BLER is low, with peaks of about 30-40. The BERL parameter is high, but still normal. Among the second encoder mistakes, there’s only a scattering of E12 errors. The Land Jitter is slightly above the norm, but this doesn’t affect the Land Histogram where there are no adjacent areas. The Pits fit into the norm, too, although adjacent areas in the Pit Histogram are very close to each other. That is a very good result for the maximum write speed. Let’s drop it down to 24x and watch the outcome.

We’ve got surprises here. The quality of the written disc degenerated considerably in comparison to the 52x disc. The higher BLER and the worse symmetry in the middle of the disc can be put up with, but the Land Jitter is too high and the look of the Land Histogram is not pleasing at all. Areas overlap up to sequences of 10T and 11T. The Pits are all right, though.

Well, this one is a tricky device. It is good at writing discs at its maximum speed, but worse at 24x. I recall the same thing with MSI’s CD-RWs with earlier firmware versions. MSI solved that problem thereafter. Probably the next firmware version of the SM-352N will deal with this problem, too.

Samsung TS-H492A

The BLER is higher than with the previous model, but is still in the acceptable range. There are fewer second encoder errors. A single surge of errors at the end of the disc is due to a physical defect of the medium and is no fault of the drive. The BERL is smaller, three at the maximum. The Jitter is always normal, both in Lands and in Pits. However, the Pit Histogram shows that adjacent areas of small-length sequences do overlap. Overall, the quality of writing is similar to the previous model. I could have said it is high if it were not for the Pit Histogram.

Now let’s reduce the speed to 24x.

And again, strange things happen. The overall burn quality has improved; at least there is no overlapping in the histograms. The BLER diminished, too. But the BERL has increased, the C2 error count has grown, too, and the disk symmetry has deteriorated. Once again, we see a drive from Samsung to behave strangely at a lower burn speed. Maybe they tuned the drive up for high speeds only?

It’s real hard to select the best CD-R burner among the three tested devices. One model may be better in one set of parameters, but worse in another set. The AOpen COM5232/AAH looks the most balanced of all, producing discs of an acceptable quality at the maximum and reduced speed alike. However, you don’t get any considerable quality gain by reducing the burn speed. Samsung’s drives burn better than the AOpen at the maximum speed, but are less successful at the reduced speed. I can’t say that any of the Samsungs was better than another in my tests.

Overall, the three tested drives do not aspire to be anything more than “average” devices in terms of quality of the burned CD-R discs. There are models with even worse parameters, but there are also much better drives available in the market.

 
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