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Recommendations For Creating and Delivering Mix Master Files

Digital Audio Precisions: Sample Rate, Bit Depth, and Audio File Type

The Producers and Engineers Wing of The Recording Academy recommends that digital mix

masters be delivered as 24-bit, split or stereo-interleaved Broadcast Wave files (.BWF), withsample rates equal to or higher than 88.2kHz. Follow these recommendations for the best results.

Lower sample rates like 44.1kHz are fine when unavoidable, but it is highly recommended that 24-bit mix masters be delivered to the mastering process. Mix masters recorded at 16-bit can beperfectly fine in and of themselves, but 24-bit mix masters allow for higher resolution processingduring pre-mastering. Mixing engineers should generate a separate set of 16-bit reference bouncesfor their clients.

When in doubt, dont change. For less experienced mixers, the easiest choice for generating mixmasters from DAWs like Pro Tools and Logic is simply to use the same sample rate and bit depth

settings as the source mixing session. In general, sample rate conversion and re-quantizing are bestaddressed at the end of the pre-mastering process.

Mix Master Levels

It is recommended that 24-bit mix masters be bounced with peak amplitudes between -6.0dBFSand -3.0dBFS. While there is no reason to leave any headroom for the mastering process itself,several circumstances suggest this range as a best practice:

Metered peak amplitudes greater than -3.0dBFS can often include significantly higherinter-sample peaks, including material beyond -0.0dBFS.

Many mixing environments lack the metering and monitoring tools to detect theseinter-sample peaks.

At approximately 144dBFS, a 24-bit digital audio file has dynamic range to spare.It is not productive for mixing engineers to use peak limiting on the mix buss to achieve higheraverage amplitudes (louder mixes). Loudness is most successfully addressed in the masteringprocess. Rather, mixers should simply use the master fader to adjust peak amplitude. If clientscomplain about low volume, peak limiting can be used on their 16-bit reference mixes.

What To Bounce?

1. In addition to the Final Mix or album version of each song, it is often useful for artists, record

labels and mastering engineers to have both Instrumental and A Cappella versions of mixes.These mix reductions can be simply generated by alternately muting all vocal or instrumentalcontent, and re- bouncing the same timeline as the Final Mix.

2. If mix-buss processing like compression, EQ, or peak-limiting is being used on the Master Fader,bounce mixes both with and without the buss processing. These processes can often be moreconsistently applied during the mastering process than they can be on individual mixes. That said

Copyright 2011 Anthem Mastering

8/13/2019 Recommendations for Delivering Mixes

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its always useful to hear examples of what sounded good during mixing sessions. Be sure to clearlylabel all mix master files to reflect their variation. Here are some labeling examples:

ArtistName_SongTitle_FinalMix.wavArtistName_SongTitle_Instrumental_NoBussProcess.wav

ArtistName_SongTitle_VocalUp.wav

3. Organize digital mix masters (bounces) in folders. Heres an example:

Further Reading

Recommendation for Delivery of Recorded Music Projectshttp://www.grammy.com/Recording_Academy/Producers_And_Engineers/Guidelines/

0dBFS+ Levels in Digital Mastering (AES Paper about Digital Gain Staging)http://www.tcelectronic.com/media/Level_paper_AES109.pdf

Copyright 2011 Anthem Mastering