Mastering is a process that’s separate from production, as well as mixing; it involves preparing your song for distribution. Mastering requires a unique set of skills, and equipment, which is why people often choose to outsource a mastering engineer. Typically, a producer writes a song, and then sends it off to a mixing engineer who ensures all the elements of the song sound good together. From there, the mixing engineer sends the song off to a mastering engineer who applies buss processing (if required) and formats the song based on how it’s being distributed (CD, vinyl, streaming, etc.).
The way that this process manifests itself isn’t always in such a cookie cutter way. A lot of the time, one person will take on the role of producer and engineer, or even take opt to master their songs themselves. Most anyone with a decent computer can produce a “mastered” track these days. In fact, home studio owners and bedroom producers routinely “master” their tracks with an EQ and a limiter, or a full suite of mastering plug-ins.
However, a process as crucial as mastering is really best left to a professional mastering engineer, working in a professional mastering facility, with dedicated mastering tools. There are way too many things that can go wrong when plug-ins are haphazardly applied to a mix. Even if you own a mastering plugin suite like iZotope’s Ozone, it won’t provide the neutral listening environment that a mastering facility will provide.
If you do choose to outsource mastering work, there are a few simple steps you can take in order to make the process go smoothly, and ensure you get your mastered songs back quickly.
1. Finalize Your Mix
Your final mix (which is the one you will be sending to your mastering engineer) should be as close to your creative vision as possible. This typically means that the levels are appropriately balanced, there are no wayward peaks or inaudible sections, and the mix is reasonably similar in tonal quality to other tracks within it’s genre. As mentioned previously, mixing is an altogether separate process from mastering and as such, it would be best to cover it on it’s own.
2. Remove Stereo Buss Processing
If you’ve applied a compressor, limiter, or anything else to the stereo buss in order to reduce the dynamic range of your final mix, remove it. It’s common practice to have the entire mix pass through some sort of “finalizer” or “maximizer” plug-in to get client approval, or to approximate the sound of the master, but reducing dynamic range in this way takes away a fair degree of control from your mastering engineer; it’s easy for them to apply processing, but not easy for them take it away.
You can always provide your mastering engineer with two versions of your mix: one with a limiter on the master buss, and one without. The engineer can master the ‘raw’ version, and use the processed version as a reference for how you want your track to sound.
3. Leave Space at the Beginning and End of Your Track
Make sure that you aren't trimming any information off the start or end of your track. Many new producers make the mistake of rendering only the region in between the ‘start’ and ‘end’ loop markers of their DAW. This can result in lead-ins being omitted from the start, or sustained sections or reverb tails being chopped off from the end. To prevent this from happening, leave a bit of space before the start, and after the end of your material.
Even if you’ve recorded and mixed your track in a professional studio, theres probably still some noise present in your track. Although you do want to send your mastering engineer the cleanest possible mix, you don’t necessarily want to trim every tiny bit of noise from it.
Leaving some noise at the beginning and end of your song gives the mastering engineer a noise “print” or sample to work with, which is essential for effective noise reduction. As with limiters and other mastering tools, your mastering engineer's studio likely has much more effective noise reduction capabilities than the typical home studio. Master buss noise reduction is, therefore, best left for your mastering engineer.
4. Don’t Rely on Your Mastering Engineer to “Fix” Your Mix
What I said about noise doesn’t apply to clicks, pops, sibilance, and plosives; these may remain undetected from the initial recording all the way through the mixing process, and they may become audible only during the mastering stage. These issues are better addressed from your end, as the mastering engineer will not be able to remove them from a mixed track without adversely affecting the rest of the audio.
5. Submit Multiple Versions of Your Track at Once
It might be a good idea to send the mastering engineer an instrumental mix of the track along with the full version. You never know if you might need an instrumental in the future, and it will likely save you considerable time, money, and effort to have both versions mastered at once. Having the instrumental and full version mastered by the same engineer will also ensure consistency if there is ever a need to use both tracks in the same environment.
6. Critically Listen to Your Mix
At this point, you'll be ready to render/bounce/export your file. Set the render region with sufficient space at the start and the end of your song. Additionally, set the appropriate bit depth, and sample rate (remember: 24-bit, 44.1kHz, WAV or AIFF is ideal), and then click “render.” If all goes well, you'll end up with a rendered audio file thats ready to send off to your mastering engineer.
Before you attach it to an email or burn it to a CD/DVD, you might want to give your final mixdown a couple more listens through different speaker systems or playback devices. As seemingly foolproof as computer technology is, there are instances wherein the rendering process can introduce artifacts. Again, these are best addressed on your end, so a few more critical listening sessions are in order.
7. Correctly Format Your File
Sending high-resolution files is absolutely essential for ensuring a quality master. It’s generally best to send 24-bit, 44.1kHz files in WAV or AIFF format. Under no circumstances should you send files to be mastered in the following formats: MP3, WMA, M4A, or AAC; these are all low resolution, “lossy” file formats that have no place in a mastering suite.
8. Send Your Mastering Engineer Metadata and Track Notes
Finally, make sure that your mastering engineer has everything necessary to produce a quality master. This goes for naming files appropriately to including all essential details in your notes. Even if you meet with the mastering engineer face-to-face, it is still a good idea to have specific requirements written down in detail.
Although the bulk of the mastering process takes place after the final mix has left your hands, there is a lot that you can (and should) do to help ensure a quality master. Instead of leaving everything to the fabled audio-wizardry of mastering engineers, you’ll find that doing some prep work will lead to a better quality product, and faster turnaround.