How to Prepare Your Mix for Mastering

Table of Contents

Guidelines on how to prepare your mix for mastering

Files Format

Audio files can be submitted in stereo (interleaved) .WAV or .AIFF formats.

Files Bit Rate

32-bit float audio files are strongly preferred, 16-bit files are OK only when 32-bit float (or 24-bit) files are absolutely unavailable.

Files Sample Rate

Submit files at the original recording and/or mix session is at. E.g. 44.1khz, 48khz, etc.

Mix's Peak Level

Please be sure that the mix is not clipping or hitting 0dBFS on the master channel.

Mix's Master Bus/Channel Processing

You can leave the processors on the master channel as long as it is not hitting or exceeding 0dBFS. However please remove the Limiter or anything else preventing the levels from exceeding 0dBFS or just in the chain for adding loudness.

Step by step guide

How to export your tracks for mastering from your preferred DAW

What not to send for mastering

Please don’t send mix files that have already been “pre-mastered”, normalized, or made extremely loud using digital processors like Limiters, Clippers, Maximizers etc.

It’s understood that in some cases, certain plug-ins on the master channel can be very important to the "sound" of the mix. If this is the case, please submit both version, one with limiter on and one without.

Mixing Advice and Tips

Eliminate noise in the mix

As you go through your mix, eliminate any noise or pops that may be in each track. Use fades as necessary to cut out any spots that may just contain recorded noise. Cleaning up individual tracks when they’re not in use within your mixing sessions can help prevent the buildup or exaggeration of unwanted noise after mastering. If this is done in the mix stage, it will keep the overall noise level down when the mastering engineer begins to equalize and compress the mix.

If you’d like any equipment noise or hiss to be removed or reduced during intros, outros, or other quiet parts where any hiss/noise is usually more noticeable, please be sure to include a sample (at least 1 second) of ONLY the hiss/noise (with no music or other sounds) before or after the song.

It is strongly recommended to very carefully triple check the final mixes for any stray noises, pops, and clicks that may become more noticeable after mastering.

Keep your mix clean and dynamic

Overusing processors especially dynamic processors (compressors) on the master bus can destroy a mix and make it difficult, if not impossible for the mastering engineer to make a great master. Unless there’s a specific sound of a master bus processor desired for the mix, it’s best to keep the master bus free of outboard processing or plugins. If master bus processing is used, make sure to notify the mastering engineer of its type and settings.

Mix Loudness/Final Level

The loudest part in a mix should peak at no more than -3db on the master bus. you’ll want to remove any pre-mastering processing from the master bus, such as a limiter or stereo enhancer. the overall volume should sound low. we’ll raise it during the mastering process. this allows me to create the proper dynamic level for radio play, cd, or mp3 duplication.

Masters Formats for distribution

The final file formats of your final masters will vary depending on the medium you are releasing your music on. It good practice to lets your mastering engineer know in advance what formats are you releasing your music so they can prepare all the final deliverables accordingly.

Format required: 16bit 44.1Khz WAV files

Common aggregators suggested by Apple Music and Spotify are:
CD BabyTuneCoreDistroKidEmubandsAWALThe OrchardRecord UnionSoundropRoutenoteBandcamp, etc.

With most aggregators, you can distribute your music via iTunes StoreAmazon MusicGoogle PlaySpotifyTIDALDeezer, etc.

Mastered For iTunes: 24bit 96khz WAV files
Most of the above aggregators and streaming platforms are already accepting MFiT files but you might need to check with your online distributor/aggregator for specific details.

Bandcamp and SoundCloud: 24bit WAV files (sample rates above 44.1k)

Format Required: DDP image or 16bit 44.1khz WAV files

A DDP image is basically a digital image of a compact disc that contains all the audio, track IDs, CD-Text, and ISRC codes.

DDP is not prone to errors that can occur with physical CDs (and CD-Rs) such as skips, scratches, and read/write errors. This is in part why it’s best to use a DDP image for your CD production master rather than a physical CD-R.

It is not recommended to submit individual WAV files for CD production. This can lead to problems with song sequencing, incorrect CD-Text, lack of CD-Text, and in some cases the audio itself can be altered if files are handled improperly.

Learn more about the DDP file format here.

The WAV files for your vinyl pre-master can be at the native sample rate of your original mixes and/or mastering session (meaning higher than 44.1k/CD quality).

Creating a single WAV for each side of the record will ensure that no changes with the space and timing between songs can occur at the lacquer cutting stage.

Sonic adjustments are often made to optimize for the vinyl format before sending it off the pressing plant or lacquer cutter. Some of the things to address during the mastering session include:

  • Ensure bass is not overly pronounced below 40Hz.
  • Reduce excessive sibilance and high-frequency content such as cymbals, hi-hats, and shakers.
  • Control the dynamics without excessive levels or distortion.

Format Required: 16bit WAV files (sample rates higher than 44.1k in some cases)

Most cassette manufacturers usually ask for 16-bit/44.1k audio though some boutique manufactures may be able to work with higher resolution audio files.

Creating a single WAV for each side of the cassette (or “program”) will help ensure that no changes with the space and timing between songs can occur. You may wish to optimize audio for the cassette format, as it may not need to be as loud and compressed, and sibilance can be an issue with certain types of tape. Check with the manufacturer for their specs.

Format Required: 48khz WAV files (with 320kbps reference mp3)

The proper format needed for licensing your music will ultimately depend on who licenses the music, and how you plan to distribute it. However, the most common audio format for video use is 48k WAV, though 24-bit/96k is becoming more common for Blu-Ray releases.

Masters Metadata options for distribution

Metadata is the details/information that the mastering engineer will embed on your final masters. Is good practice to provide this information to the mastering engineer before all final deliverables are prepared and sent out.

WAV & AIFF files don’t support the large amount of metadata that an mp3 or AAC file can contain. If you are uploading WAV files to online distribution services, expect to submit the artwork and other metadata separately as you submit the audio files for online distribution. The distribution service you use will handle the metadata tagging that is seen by the end user based on the info you enter, and what is supported by the end file format.

A DDP image is basically a digital image of a compact disc that contains all the audio, track IDs, CD-Text, and ISRC codes.

DDP is not prone to errors that can occur with physical CDs (and CD-Rs) such as skips, scratches, and read/write errors. This is in part why it’s best to use a DDP image for your CD production master rather than a physical CD-R.

It is not recommended to submit individual WAV files for CD production. This can lead to problems with song sequencing, incorrect CD-Text, lack of CD-Text, and in some cases the audio itself can be altered if files are handled improperly.

What are ISRC Codes and why do I need them?

The International Standard Recording Code (ISRC) is a code that can be embedded as metadata in your audio files.

  • ISRC codes are primarily used to identify and catalog individual songs (tracks) on an album.
  • The ISRC allows you to get paid for digital music sales by ensuring that your royalties are tracked properly.
  • ISRC codes are necessary to sell your individual tracks via iTunes and other online music distributors.
  • They are also required for any songs that you plan to offer for streaming on Spotify and other streaming services.


To generate your own ISRC, you can apply directly via the ISRC website usisrc.org
to avoid being over-charged.

You can also buy ISRC Codes from this website but if you are planning on using an aggregator to distribute your music they will create and embed the ISRC codes for you. Typically, I recommend using CdBabyDistrokid and TuneCore for this. All of these sites provide free ISRC codes as well.

A UPC (Universal Product Code) or EAN (International Article Number) is a unique code used to identify a product, such as an album, single or ringtone.

If you want to apply for a UPC issued by GS1, please contact your local GS1 office here.

When selling music online remember that you will most likely need an ISRC code for each track as well as a UPC barcode. Pandora, Amazon, CD Baby, Tunecore and iTunes all require that you have a UPC barcode for your Digital Albums.

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