The Song Path: File Formats for Mastering

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So, you’ve decided to get your tracks mastered, you’ve chosen an engineer, how exactly do you go about getting your files to him?


He/she will probably have their own method of FTP, or file transfer, which may even be you posting a CD, but check their requirements carefully, as you don’t want to taste time, effort and money having to re-send discs because they asked for data not audio etc etc


So, what format should the files be in?


Your files should be at the highest quality possible. Definitely no MP3 or other compressed files will do really. Engineers will ask for uncompressed audio files.

So if you recorded at 48kHz, then the mix files should be 48 kHz. You should really be recording at 24 bit, so your mixes should be 24bit masters (and hence an audio CD may be returned as it will be at 16 bit as per the CD standard)



Well, you want the mastering engineer to do the best job that they can, so you need to give them the best quality files that you can. 24 bit recording gives you a greater dynamic range than 16 bit (as there are more bits with which to record the data).

Some engineers will convert anything that isn’t already at 44.1kHz to this sample rate, but that should be their decision, and they can use their own tools to do it.

As for why not MP3 files, well, an MP3 (or Mpeg 2 Audio layer 3) is what is known as a ‘Lossy’ format. It reduces the filesize (good for streaming online, or fitting on your ipod) but in doing so degrades the audio – it throws things away, it thinks it does not need, and as such reduces the data size of the stream.


So, giving a mastering engineer an MP3 to work with is akin to asking him to start off with something that is already seriously degraded. The expression ‘polishing a turd’ comes to mind. Now, you may think you can’t hear a difference between your MP3 and your wav files (and at higher bit rates, you may be right to a point), but once the mastering engineer begins to work on the material, by compressing and limiting the material, and generally ‘making it sing’, this will bring the sound of the artefacts that the processing generates, to the forefront of the balance, and you’ll hear them..


Dynamics Processing

As with quality of files, you really want to give the mastering engineer mixes that do not already have any dynamics processing on the main stereo output at all. Whereas some engineers like to give clients mixes which they have put through an L3 limiter (by Waves), it is best to give mastering engineers dynamically un-limited files.


Why? Well again, you want your mastering engineer to have the best chance at processing the track, and this will include some dynamics processing, so give him he best chance he can have a this. By all means, send  them a copy of the ‘Limited’ mix that the engineer gave you and ask him/her to refer to that.


Zipping Up Files

If you are uploading your files to a dropbox, or FTP server, it is a good idea to zip them up before you upload them. There are a few reasons for this, filesize not really being one of them. The system offers a system of error correction, so the file that your engineer gets is more likely to be the one you send..



Ask Your Engineer

Don’t be afraid at any stage to ask your engineer if you don’t understand something. Remember – you are the client here! You should be confident in the money you are spending. Even get your mastering engineer to speak to the engineer who mixed your tracks if it will help..


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