Matrix Numbers

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Like the catalog number, the ISRC and the EAN code, the matrix number is an additional information which can help to identify a sound recording. It consists of engraved (and/or printed) characters located around the label of a vinyl record. By extension, the terms "matrix numbers" may also refer to the complete sequence of codes visible around the inner circle of a CD. These characters and codes are used by the factories in the stages of records pressing.

It is important to notice that:

• several records manufactured in the same series usually have exactly the same matrix numbers, this is not a unique identifier for each individual item
• records containing different sound masters might have same matrix number, so this might not be a unique and infallible way to distinguish different versions
• reversely, records having exactly the same content can have different matrix numbers

Vinyl

Definition from the Elektra Master Discography FAQ by Andy Finney, August 2006:

"When a vinyl disc was made, the first stage (after recording the music of course) was to cut an [sic] master disc, usually on an oversized disc made of aluminium coated in acetate or lacquer. A heated stylus (sometimes cooled by helium) would literally cut the groove of the disc into the lacquer and this master would be coated, electroplated (usually more than once) and finally stamped in a steam-heated press to produce the vinyl disc. In order to identify the acetate disc used to make a particular disc the cutting engineer would inscribe or stamp a reference number into the surface of the cut disc, between the end of the music and the space for the label. This is where the run-out-groove or scroll would be. Often this so-called Matrix Number would just be the disc catalogue number with A or B or 1 or 2 after it to show which side. Sometimes obliterated matrix numbers on discs can show changed release schedules.

Some companies (such as EMI on discs such as the 1960s Beatles albums) decoupled matrix numbers from catalogue numbers although there would almost always be a listing of the matrix number on the disc label. Even in these cases the matrix for the 'A' side would be lower than that for the 'B' side. In this way you can often identify discs where the A and B sides have been 'flipped'. Other information would sometimes be added to denote the pressing plant (many Elektra discs have this since individual LPs were pressed in more than one plant across the US) or give a sequence number to the cut or stamper. In the 1970s it became the fashion for disc cutting engineers to 'sign' their matrixes. (An example being Porky's Prime Cut') Sometimes cryptic remarks would be inscribed, and on one notorious occasion an Elvis Costello album had a message in the run-out asking people to phone the record company press officer and claim a prize! (But I digress.)

Elektra albums usually had matrix number consisting of the catalogue number and the side, but the 10-inch discs had JH numbers."

For instance, the matrix numbers engraved on Baby Snakes BPR 1115 side 1 are P. BPR-1115-AS-RC1 (1) Dinkum

BPR 1115 side 1 matrix numbers

CD

RCD 10546 Matrix numbers

The following paragraphs are illustrated with Francesco Zappa RCD 10546 which matrix numbers are IFPI 2U3Q WEA mfg. OLYPHANT ifpi L901 W6063 A4 P2 310546-2 01 M1S1

SID Code

The SID Code^[1] is an anti-piracy standard defined by the IFPI^[2] and Philips^[3] in order to track the source of optical discs mastering and replication. The use of SID Codes started in 1994 and grew until nowadays it has become almost systematic.

Since not all plants have both mastering and replication facilities, two identification codes have been implemented:

• the Mastering SID Code that identifies the plant that manufactured the master
• the Mould SID Code that identifies the plant where the disc was replicated

Mastering SID Code

Sometimes also refered to as LBR Code (Laser Beam Recorder Code), it indicates the plant and LBR that manufactured the master or stamper used for the disc production.

RCD 10546 Mastering SID Code (IFPI L901)

It consists of the letters “IFPI” followed by a four or five alphanumeric digit code commencing with the letter “L”.

Example: the Mastering SID Code printed on Francesco Zappa RCD 10546 is IFPI L901

The Mastering SID Code must:

• Be positioned between 18.0 mm from the centre of the disc and the start of the “lead-in” (which is at a radius of 22.9 mm from the centre).
• Be a minimum of 0.5 mm high.
• Be legible without magnification.
• Be located in the metallised region of the disc.
• Read from left to right when viewed from the read-out, or play side of the disc. However many records seem not to follow this recommendation.
• Be installed in either the firmware of the LBR (i.e. the software that forms an intrinsic part of the machinery and is not readily accessible by the operator of the facility) or embedded in the system controller (i.e. the signal processing system that controls the operation of the LBR) in such a way that the operator of the system is not able to alter or remove/disable the code.

It is recommended that the space allocated exclusively for the code (determined by the user and LBR supplier) shall consist of an arc of 30º for the Mastering SID Code. It is mandatory that it is clearly separate from other features.

Mould SID Code

The Mould SID Code indicates the plant where the disc was replicated and a serial number which can be set freely by the plant.

RCD 10546 Mould SID Code (IFPI 2U3Q)

It consists of the letters “IFPI” followed by a four or five alphanumeric digit code. The first two digits (in the case of a four digit SID Code) or the first three digits (in the case of a five digit SID Code) are assigned to the operator of the manufacturing or mastering plant by Philips Intellectual Property & Standards. The last two digits of this code are allocated by the plant to give each mould on the site, including spare moulds, a unique code.

Example: the Mould SID Code printed on Francesco Zappa RCD 10546 is IFPI 2U3Q

Remarks:

• The implementation guide implicitely recommends not to use “I”, “O”, “S” and “Q”. However many records seem not to follow this recommendation.
• The Mould SID Code must be positioned within the zone that has a maximum radius of 22.5 mm.
• If Burst Cutting Area - Code is used, then the position of the Mould SID Code will be adjusted to compensate.
• The Mould SID Code must not be imprinted in the clamping area.
• The Mould SID Code must not be placed in an area that obscures the Mastering SID Code or any other user defined characters.
• The Mould SID Code must be imprinted on all substrates whether containing valid programme content or not, including blank discs, and even if not metallised. Overprinting of the Mould Code for decorative purposes is permissible.

Code 39 (barcode)

RCD 10546 Code 39 (049450, decoded)

This barcode^[4] is used to encode uppercase alphanumeric characters (A through Z and 0 and 9) and a few other characters such as the dollar or minus signs. This barcode is called Code 39 because there are 9 light and dark bars in each character code, and 3 of these bars are wide (39 means 3 "wide" of 9 "bars").

Example: the barcode printed on Francesco Zappa RCD 10546 is

which can be decoded as 049450.

DVD

SID Code

The DVD SID Code follows the same rules as the CD plus addionnal requirements:

• The Mastering SID Code must be placed within the zone that has a maximum radius of 22.5 mm.
• If Burst Cutting Area - Code is used, then the position of the Mastering Code should be adjusted to compensate.
• No minimum radius is specified, but due regard should be paid to the following points:
  • The Mastering SID Code must be located in a metallised region of the disc.
  • The Mastering SID Code must not be obscured by the stack ring.
  • It is recommended that the space allocated exclusively for the code (determined by the user and LBR supplier) shall consist of an arc of 30º for the current code. It is mandatory that it is clearly separate from other features.
  • A further arc of 30º shall be reserved for future use.

Single layer, single side disc

If the dummy side of the disc is made from a scrap program disc, it shall bear the SID Code, even if not metallised.

Dual layer, single side disc

The Mastering SID Code must be recorded for both layers (Layer 1 and Layer 0 in DVD format discs). At least one of the Mastering SID Codes (for either Layer 1 or Layer 0) must be clearly visible.

Single layer, double side disc

The Mastering SID Codes must be recorded on both sides of the disc. It is desirable that both Mastering SID Codes are clearly visible, but it is acceptable if the code is obscured due to restrictions of the printed area.

References

1. SID Code Implementation Guide^{[dead link]}
2. International Federation of the Phonographic Industry (IFPI) Official Website and IFPI
3. Philips Official Website and Wikipedia:Philips
4. Wikipedia:Barcode

See Also

• Article about the history of matrix numbers before the rock era: Matrix and Catalog Numbers in G&S Discography.
• Wikipedia Matrix Numbers article
• ISRC Structure and FAQ
• IFPI Codes
• Matrix Numbers And Other Run-Off Markings @7tt77.co.uk
• Common runout groove etchings: how to list them (Version 6) @Discogs
• CD matrix barcodes @Discogs

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