Mastering Format Guide

Updated September 2021

Online Distribution

iTunes, Spotify, Amazon, Google Play, Rdio, Deezer, Rhapsody, Tidal, Beatport, YouTube + many more

Format required: 24bit 44.1 to 96k WAV

Apple Music, Amazon Music, Deezer, Tidal, Qobuz now all offer lossless streaming and downloads. Spotify have also announced an ‘HD’ service ‘coming in 2021’. This is great news for artists, listeners, and mastering engineers. Finally, we can stream music as we intended with no loss in quality.

Most digital distributors now accept higher resolution files with a notable exception of CDBaby. With this in mind, I will now be offering this format as standard plus 16bit 44.1k and 320kbps MP3.

Apple Digital Masters (formally ‘Mastered for iTunes’)

Format required: 24bit 44.1 to 96k -1dBTP WAV

Apple Music are allowing artists to supply higher resolution masters which are marketed as “Apple Digital Masters”. Formally branded as ‘Mastered for iTunes’. You will need to check to see if your online distributor supports this format. Only mastering engineers that are certified by Apple can supply compatible masters. Steve Kitch was one of the first mastering engineers to sign up to supply this format.


Format required: DDP

The best format for CD duplication is DDP (Disc Description Protocol). This is a digital format that can be uploaded online for speedy delivery. It has an error-checking system built in to ensure that the master can’t get corrupted. Steve Kitch Mastering supplies an accompanying Mac/PC software player which allows you to load the DDP, check order, gaps, text, codes, etc. From this software, you can also burn your own CD reference copies and create WAVs.


Format Required: 24bit WAV files with sample rates 44.1k and higher. 1 file per side.

Most vinyl plants allow you to supply masters in a high resolution. Supplying a file for each side means you can specify your own gaps. It’s recommended to go for more dynamic/less limited masters since there are no loudness wars. It also sounds better! Vinyl masters are accompanied with track sheets for the cutting engineer.


Most cassette replicators will request 16bit 44.1k masters. Supplying a file for each side means you can specify your own gaps. Cassette masters are accompanied with track sheets for the cutting engineer.


Format Required: 24 bit 48khz

If your audio is destined for video, TV, DVD, Blueray then you’ll probably have to supply your master at 48Khz as this has been the default for audio for decades. It’s best to check with your producer first and let us know what you need.


If you have a publishing/syncing company then check to see what formats they prefer to hold on file. A lot of publishing companies will request instrumental versions to help with syncing with TV and film. It’s best to master the original and any variations at the same time to save on costs. However, all settings are archived in case you need to supply these at a later date.