Mastering Formats Guide

Online Distribution / Streaming Platform Mastering Formats

Format required: 24bit 44.1kHz to 96kHz WAV

Apple Music, Amazon Music, Deezer, Tidal and Qobuz now all offer lossless streaming and downloads. Spotify have also announced an ‘HD’ service which was ‘coming in 2021’ but that seems to have gone a bit quiet. This is great news for artists, listeners, and mastering engineers. Finally, we can stream our music as we intended with absolutely no loss in quality.

Most digital distributors now accept higher resolution files so this is the format that I supply as a default. A notable exception is CDBaby who still only accepts 16bit 44.1kHz files. With this in mind, I will now be offering a range of formats as standard including 16bit 44.1k and 320kbps MP3.

Mastering Formats

Apple Digital Masters (formally ‘Mastered for iTunes’)

Format required: 24bit 44.1kHz to 96kHz -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: 24bit 44.1kHz to 96kHz WAV

Bandcamp will accept 24bit files with a sample rate of up to 96kHz. The artist can decide if they will allow their fans to download these higher resolution files.


Format required: 24bit 44.1kHz to 96kHz WAV

Soundcloud now accept 24bit files with a sample rate of up to 96kHz. However, they will stream your audio at a much lower, lossy quality.


Format required: ‘High quality’ MP3

For press kits and emails, most people still prefer MP3s due to their smaller file size and convenience. As standard, I provide 320kbps MP3 files however these should NOT be used for anything else!


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 44.1kHz and higher. 1 file per side. Plus track sheet for cutting engineer.

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.


Format Required: 16 bit 44.1kHz

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.

If you have any mastering format requirements not listed here or have any further questions on mastering formats then please get in touch here.