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Quality of the DVD+R disc recorded at 12x speed

And once again the drive uses a Z-CLV algorithm consisting of four zones, so less than a quarter of the disc is actually recorded at 12x. That’s why the drive takes almost the same time to produce a recorded disc at 12x and 8x speeds. And of course, it is much slower than its market competitors.

As for the quality of the resulting disc, it is high, with a very low rate of PI errors and failures and a small total of PIE blocks. There’s a single peak of four PI failures at the second half of the disc, but it’s too small to affect its readability.


Beta/Jitter and TA Test (Outer) for the disc recorded at 12x speed

The Beta graph allows you to see the moments when the drive increased its burn speed (curiously enough, the drive reduces the laser power rather than increases it as it switches over to 12x speed). Overall, the fluctuations of Beta are within the acceptable limits. The Jitter rate is changing along the surface of the disc, growing up at higher burn speeds, especially on the outermost tracks (which were recorded at 12x). This is also clear from the TA Test results for the outermost tracks. The drive can’t accurately maintain the required lengths of pits up to 10T – you can see overlapping lobes on the diagram. The Peak Shift value is rather big, too. Despite all this, however, the overall quality of the disc is quite high. It’s not ideal, but you are unlikely to meet any problems with the readability of the disc.

To finish with the DVD+R format I will test a dual-layer medium.


Quality of the DVD+R DL disc recorded at 2.4x

The drive recorded the blank successfully, without slowdowns. But the jaggedness of the speed graph we have noticed above can be observed here, too.

The quality of the resulting disc is far from perfect. Even at the minimal burn speed the PIE/PIF rate on the first layer exceeds the acceptable limits, especially at the beginning of the disc. The situation becomes normal towards the middle of the first layer where the error rate becomes acceptable. A minor surge of PI failures is observed then as the drive switches from one layer to the other. The second layer is recorded excellently, with a low rate of PI failures and errors and total lack of error peaks.


Beta/Jitter and TA Test (Outer, layers 0 and 1) for the DVD+R DL disc recorded at 2.4x speed

The Beta graph is normal, being nearly horizontal. But you can see that it is divided in two parts at the point where the drive went over from the first to the second layer, accompanying this with a minor increase in the laser power. The Jitter rate is uniform within the same layer, but differs between the two layers as you can also see on the diagram.

The TA Test results show that the drive burns the pits and lands of the necessary length on the first layer: adjacent lobes do not overlap on the diagram and the Peak Shift is very small. Jitter quite expectedly grows up on the second layer of the disc, but the Peak Shift, on the contrary, is smaller than on the first layer.

Summarizing the results of the drive with write-once media, I should note that it met no serious problems with any of the media formats. There are some minor imperfections like inaccurate pit/land lengths, but they do not affect the overall quality of the discs much. However, the drive performs worse with dual-layer discs than with single-layer ones, despite the low burn speed it works at – the error rate is much higher than normal on the first layer. The manufacturer will hardly release a firmware update to correct this issue, so you should keep this fact in mind if you want to purchase an AOpen DUW1608/ARR.

Next we will check the rewritable formats.

 
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