Writing Data CD-R discs:
The specifications of the LG GH22LP20 state that the drive is able to write CD-R discs at 48X and CD-RW at 32X.
For our data writing tests, we simply burned a full disc using CD-Speed (create data disc) function and burned the discs at the maximum speed allowed.
Let us find out how the drive really performs in speed and quality.
We will test CD-R discs from many different CD-R manufacturers. To really measure the write speed, we used the “create data CD” function in Nero CD-Speed. The discs were written at the maximum speed that the drive supports. For the quality test, we used Nero CD-Speed’s Disc Quality Scan and combined this with a Transfer Rate Test to test if the resulting disc was readable. Also note that different drives and different reading speeds may affect the results obtained when scanning the discs. We used a Lite-On SOHR-5239V drive with firmware 2S0E and scanned the discs at 48X speed.
There is more than one way to handle C1 and C2 error detection/correction, but a simple and common way is to detect and correct up to two errors per frame in each stage and detect three or more errors:
E11: 1 error detected and corrected by C1 layer
E21: 2 errors detected and corrected by C1 layer
E31: 3 or more errors detected but not corrected by C1 layer
The sum of these (per second) is called the Block Error Rate: BLER=E11+E21+E31
E32: 3 or more errors detected but not corrected by C2 layer
Any E31 is un-correctable by the C1 layer and will result in the bytes in that frame being redistributed into multiple frames which are passed to the C2 layer.
Any E32 is un-correctable by the C2 layer and will result in interpolation being used for Audio CDs or will result in third layer error correction being use for Data CDs.
Different drives have different ways of reporting these errors in a Disc Quality scan. Lite-On CD-RW drives will report C1 and C2 errors this way:
Here is an easier way to look at Disc Quality Scanning:
A written CD-R disc will always have some C1 errors; C1 errors are easily corrected by the drive’s error correction capabilities. The next level of errors is C2, while C2 errors could also be corrected by most drive’s error correction capabilities; they are not wanted on a good quality disc. A good disc should not contain any C2 errors, and preferably have an average C1 error amount of below 2.0 for the best discs, or at least below 10.0 averages for good quality discs. After C2 errors, there are only un-correctable errors that will make a disc unusable.
In short, our analysis will be based on this guideline to determine the quality of the burned disc:
CD-R/RW quality scans guideline
Below are the obtained results:
C1 errors of 2.97 average with no C2 errors places this verbatim media in the “Good” category.
The HP media manufactured by CMC Magnetics has burned with very good quality.
The LG GH22LP20 does excellent with the media from Ritek.
Here again, the LG GH22LP20 produces a very good quality burn, this time with our Fuji media.
CD-R LightScribe disc from verbatim results are very good with the LG GH22LP20.
Writing Quality with Re-Writable discs:
The results were far from acceptable with our 32X Verbatim test media.
Let’s take a look at the performance of the LG GH22LP20 when writing to 12X Memorex CD-RW media.
While only able to write our 12X test media at 10X the outcome is much more desirable.
CD-R writing quality is excellent. We would like to seem better performance when writing to our 32X CD-RW media; as shown above the LG GH22LP20 writes to our 12X CD-RW media with much better results.
Now let’s head on to the next page where we will test DVD recordable performance….