Frequently Asked Questions

What is ISRC?

ISRC (International Standard Recording Code) is a unique identifier that is assigned to each recorded track or audio recording. It is used to identify and track the use of recorded music.

The ISRC system was developed by IFPI in order to provide a standard way of identifying and tracking recorded music. Each ISRC is a 12-digit code that consists of a two-letter country code, a three-letter registrant code, a two-digit year, and a five-digit identifier. Read more about ISRC here.

In order to obtain ISRC codes, artists and music industry organizations must register with a national ISRC agency, which will assign them a registrant code and provide them with the tools and resources needed to generate ISRC codes for their tracks. You can find the ISRC agency in your country here.

During mastering, ISRC codes are typically added to the DDP files used for CD replication. This is the primary use of ISRC codes during mastering.

It is also possible to add ISRC codes to the wave files used for online distribution. If you provide us with the ISRC codes before mastering we will add them to the files. Keep in mind that when uploading your files to a distributor or aggregator, they may only use the metadata that you enter and may ignore any metadata within the audio files themselves.

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What are UPC / EAN codes?

UPC (Universal Product Code) and EAN (European Article Number) codes are both types of barcodes that are used to identify and track products, primarily in the retail and manufacturing industries.

UPC codes are used primarily in North America and other regions that use the North American numbering system, while EAN codes are used primarily in Europe and other regions that use the European numbering system.

UPC codes are 12 digits in length, while EAN codes are 13 digits in length. To convert from a UPC to an EAN code, you need to add a leading zero to the UPC code.

There are a few ways to obtain UPC or EAN codes for your record release:

  • Contact your record label or distributor: If you are working with a record label or distributor to release your record, they may be able to provide you with a UPC or EAN code.
  • Purchase a UPC or EAN code: You can also buy a UPC or EAN code from a company that specializes in providing these codes. These companies can often be found by doing an online search for one in your region.
  • Use an aggregator: Some aggregators, which are companies that help artists distribute their music to different platforms, may also be able to provide you with a UPC or EAN code.

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What is a DDP premaster?

A DDP (Disc Description Protocol) master is a type of digital master that is used in the production of audio CDs. It is a file-based format that contains all of the information necessary to produce an audio CD, including the audio data, CD text, ISRC, UPC/EAN, and other metadata. It is the standard way to deliver masters to CD pressing plants and the DDP is usually delivered as a zip file.

To listen to a DDP file, you will need a DDP player application. When you receive your DDP files from us after mastering, they will be accompanied by a player application that is compatible with both PC and Mac. To use the player software, simply download the zip file, unzip it, and launch the application from the “Player” folder.

When sending the DDP file to a pressing plant, it’s important to ensure that you send the zip file exactly as you received it from us. Do not alter the contents of the zip file in any way.

To create a DDP premaster, we typically need the following information:

  • Album title
  • Artist name
  • Track titles
  • ISRC (one for each track)

The album title, artist name, and track titles will be embedded as CD-Text on the CD. It is not mandatory, but it is very common. The ISRC is also not a mandatory requirement, but it is commonly used.

We can also include the UPC or EAN if it is provided.

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What is CD-Text?

CD-Text is a data format that can be added to an audio CD to store additional information about the content. This information can include the album title, artist name, track titles, and other metadata. CD players that support CD-Text can read this information and display it on the player’s display.

However, CD-Text information may not be displayed when the CD is played in a computer. In this case, the information displayed may come from an online database (CDDB).

The information that most often is stored in CD-Text is artist name, album title and song titles. It is also possible to store composer name(s) and custom messages, although these are rarely shown in most CD players.

We will add CD-Text if we have all the information available when creating the DDP.

Note that you will enter the metadata for online platforms separately when uploading the audio files to the distributor or aggregator.

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What are files for online distribution?

Files for online distribution are digital audio files that are optimized for distribution through online platforms such as streaming services, download stores, and social media. These files are typically in a standard stereo wave format and have a sample rate of 44.1 kHz and a bit depth of 16 bits. This type of file is widely accepted by major online platforms, such as Spotify, YouTube, Apple Music, and others.

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What are high resolution files?

High resolution audio files are digital audio files that have a higher sample rate and bit depth than the standard audio files for online distribution, resulting in a higher quality and more detailed audio experience. These files contain the same audio content as the standard online files, but at a higher resolution. High resolution files typically have a bit depth of 24 bits and a sample rate that matches the original mixes.

High resolution audio files can be used on a variety of online music platforms, such as Bandcamp, Tidal, Apple Digital Masters, Qobuz, HDtracks, and others. These platforms allow users to purchase or stream high resolution audio tracks and albums.

Stockholm Mastering is approved for delivering high resolution masters to Apple Digital Masters (ADM), which was formerly known as Mastered for iTunes (MFiT).

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What is a master for vinyl cutting?

A master for vinyl cutting is a special version of an audio recording that is specifically prepared for the process of cutting a vinyl record. This master is typically delivered as a single, continuous wave file for each side of the record, along with a timing sheet that specifies the start time and length of each track.

The vinyl cutting master may also have less peak limiting applied to it, in order to ensure that the resulting vinyl record has the best possible sound quality. For more information you may want to refer to our article about mastering for vinyl that provides more detail.

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How do I credit the mastering?

We appreciate it if you include us in the credits for your record! Here are some suggestions for how you can credit us:

Mastered by Sofia von Hage and Thomas Eberger at Stockholm Mastering
Mastered by Sofia and Thomas at Stockholm Mastering
Mastered at Stockholm Mastering

Feel free to use any of these options or come up with your own way to credit our work. We are grateful for the opportunity to be a part of your project and are happy to be recognized for our contributions.

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Do you master all records together?

Yes, both of us are actively involved in the mastering of each record. One of us may do the majority of the work on a record, but we always collaborate and make final adjustments together before anything is delivered. This ensures that the mastering process is thorough and that the final product meets our high standards.

You can find more information about our workflow in this video from our YouTube channel: