User:UltimateRiff/CD Manufacturing and Matrix Guide
after a brief dive into the world of CD manufacturing, I thought it’d be good to have this information in one spot.
feel free to edit this with new information~
The Basics
but what even is an matrix? well, you came to the right place! 😉
you’ll find the matrix on the inner ring on any CD, DVD, or Blu-ray, usually on the bottom (silver) side of the disc, but on some older discs it’ll be visible from the top. there’s a couple examples on this page.
in addition to an alphanumeric code around the ring (aka mirror band), on discs made after 1994 there are two numbers marked IFPI; these are the mastering and mould SIDs.
taking the second example to the right, the mastering SID can be read as IFPI LT05 underneath where it reads “6037 - FIVE IRON”. mastering SIDs appear in the mirror band and always start with “L”. this can tell you where the glass master for the disc was made. note that mould SIDs can also start with “L”.
the mould SID is usually harder to spot. it’s molded into the plastic of the disc in the (usually) clear part around the hub. as such, it doesn’t usually show up on scans (IFPI A603 is barely visible near the top on the right example). an example picture of a typical mould SID; top left, just on the edge of the light. this code can tell you where the disc was pressed.
sometimes, you’ll also find the pressing and mastering credits in plain text in the matrix or pressed into the hub. for example, many EMI Uden glass masters are credited as such, and the right example has RAINBO CA stamped in the clear hub area (can barely be made out near the bottom of the image).
SID codes
each SID actually refers to a different machine, either a Laser Beam Recorder (LBR) for glass masters, or a stamper or unique mould for pressing, kind of like a signature.
there are several lists of IFPI codes, including ones from redump, Pink Floyd Archives, Madonna Discography, and others. some may be more up-to-date than others. Discogs label pages also often include a list of SIDs related to a particular pressing plant or label, see EMI Uden above or MediaMotion, for example.
do note, however, often SIDs can be transferred due to different plant owners, so they don’t always relate to a label exactly one-to-one (although places are more stable? need confirmation). see how IFPI 15## is both used by EMI Uden and MediaMotion at different times.
How to Credit
note, there is currently no real standard as to how to enter matrix codes in the annotation, this is just how I do it.
to get nice-looking headers like the ones here and to make annotation searching easy, you can copy this into the annotation:
== Matrix ==
=== Disc one ===
* {company logo} #####@@-##@@ ('''Mastering SID:''' IFPI xxxx '''Mould SID:''' IFPI xxxx)
=== Disc two ===
* {another matrix code goes here}
you should start the code at a place that makes sense, usually after the barcode section (when it exists).
for company logos, I put them in curly brackets, occasionally I’ll also link to an image of the logo from Discogs, if I think it’ll help. if there’s already an annotation, I’ll usually add the matrix to the bottom, since more often the annotation that’s already present is more generally interesting and helpful for identification than the matrix code.
On Label and Place Pages
I don’t usually see SIDs listed on MusicBrainz label and pressing plant entries, but there’s no reason not to add them if you wish. an example I recently added is MediaMotion’s annotation. you can also add links to other labels and pressing plants that inherited SIDs from or to the entity in question.
an example to copy-paste:
== Identification ==
The following SID codes may appear on CDs manufactured by {company name} (but as this manufacturer may have been known by other names before and/or after, SID codes should not be used to credit {company name} where its name is not shown).
=== Mastering SID codes ===
* IFPI ****
=== Mould SID codes ===
* IFPI *****
* IFPI ****
Matrix and Disc ID for Audio CDs
the matrix code in the mirror band of a disc stands for a specific data content. this code is unique (with very few exceptions) and will not be found on discs with somehow different content.
important to the matrix data is the TOC (table of contents), a series of numbers (mainly start sectors of tracks and lead-out) from which the disc ID is calculated. thus a specific disc with its unique matrix code will always generate the same disc ID, whatever was printed on the top side.
note, that this is not true in the opposite direction. the TOC can be copied to a new glass master and then the same disc ID will also be calculated for a disc with a different code. this is common with new glass master versions made at the same plant, rarely happens with different plants. often discs with the same disc ID will show a similar code with only a forward counted number at the end. there is also the very rare case of completely different CDs which happen to have the same number of tracks with the same lengths in the same order.
knowing what matrix code the CD submitting the disc ID had is an important information. it is good practice to enter the matrix code as an edit note for each edit Add disc ID and Set track lengths.
note also, that DVD and Blu-ray discs don’t use TOCs the same way as CDs do, so they won’t have Disc IDs. the matrix data can still be important to help determine manufacturing and glass mastering info
Matrix Codes on Re-writable Media
while nearly all digital disc formats have matrix codes, not all of them have quite the same importance. for example, for CD-R and CD-RW (writable and re-writable respectively) discs, the manufacturing isn’t typically as important as for pressed discs, as the person or company doing the CD burning could have used discs from different companies, factories, etc. in a single run of a release. these can and probably should be split into seperate releases, but I haven’t seen any cases where this has actually been done.
Helpful Links
- a MetaBrainz thread with a lot of helpful information
- the original thread for this wiki page
