Something that has turned out surprisingly hard to do is to categorize CDs. While at first it seemed easier than vinyl it has turned out to be much more difficult, as CDs have been repressed in different years by different plants (or the same under a different name), but where everything is the same, except for some very minor details, such as SID codes, or the CD matrix.
I have already written about SID codes and how they can be used to very roughly date CD releases. But there is also other information that can be used to see if releases have been dated (somewhat) correctly.
Recently I decided to look at the companies that are listed, see when they were operational and use that information for checking release years.
Quite a few CDs were pressed at a particular plant in the US. During its lifetime this plant operated under different names:
There is some overlap: some glass masters produced in one period were also used later, but the start dates of these periods can be used to check if releases might have the wrong year recorded. I do this by looking if any of these four companies is listed in the Discogs XML for each release and then comparing it to the year.
There are 4368 releases in the database where one of these companies is listed, and that have a release year defined.
What is curious to see is that there is quite a sharp drop in releases. It could be that this is because the plant actually stopped producing CDs and quite a few of them had already been added to the database.
There are 76 releases where the declared release year predates the year that the plant started operating under a specific name.
I inspected a few of these releases and it seems that in the majority of cases the original release and one or more reissues were lumped together.
There are other pressing plants (also for vinyl) where I can likely use this same trick.
I have already written about SID codes and how they can be used to very roughly date CD releases. But there is also other information that can be used to see if releases have been dated (somewhat) correctly.
Recently I decided to look at the companies that are listed, see when they were operational and use that information for checking release years.
Quite a few CDs were pressed at a particular plant in the US. During its lifetime this plant operated under different names:
There is some overlap: some glass masters produced in one period were also used later, but the start dates of these periods can be used to check if releases might have the wrong year recorded. I do this by looking if any of these four companies is listed in the Discogs XML for each release and then comparing it to the year.
There are 4368 releases in the database where one of these companies is listed, and that have a release year defined.
 |
| PDO/PMDC/UML/EDC releases with defined release year in the Discogs dataset |
What is curious to see is that there is quite a sharp drop in releases. It could be that this is because the plant actually stopped producing CDs and quite a few of them had already been added to the database.
There are 76 releases where the declared release year predates the year that the plant started operating under a specific name.
 |
| PDO/PMDC/UML/EDC releases with wrong year in the Discogs dataset |
I inspected a few of these releases and it seems that in the majority of cases the original release and one or more reissues were lumped together.
There are other pressing plants (also for vinyl) where I can likely use this same trick.
Comments
Post a Comment