Mastering engineers frequently point out that many artists, band members, and even some recording engineers do not know what mastering really is. It's also hard to know for sure what can and can’t be achieved in mastering. Mastering might be an important part of their project, but it's details are often vague and misunderstood.
It’s not surprising that many artists and engineers do not know what type of files to send in for mastering. Also as important - how to prepare them! There is a lot to be aware of in the final stages of mixing. And at the end, there are expectations about how it will all sound when mastered.
Here's a short guide containing tips and tricks on how to prepare and what you can do to make the process better! In the next 10 minutes we hope to make a pre-mastering ninja out of you 🥇
Bits and kHz and all that technical stuff
Let's get the obvious out of the way first.
Exports to be sent to mastering need to be uncompressed, un-dithered, at native sample rate and highest bit-depth possible. What does that mean?
This means exporting/bouncing to .wav format at the same sample rate that your project is running at. You should also be choosing the highest number of bits available. For some that will be 24-bit, for others 32-bit floating-point.
FLAC and ALAC formats are technically speaking lossless formats as well, but importing them directly into some DAWs may prove a bit of a challenge. So to keep everyone happy, use WAV (extension .wav).
It's well worth those extra seconds on upload. It also makes sure the engineer is using his time on making your music sound great instead of juggling exotic file formats.
Bounced! Now what?
First, give it a short, concise, descriptive name. "Artist - Song - [mix version].wav" will make every engineer smile and nod in approval. It will also avoid confusion in case of later revisions. And it also makes the file easy to find with the search function in the file browser.
Check the bounced file for integrity. Listen to it from 00:00 until the very end. I know it's kind of hard at times to keep the focus on the song. Especially if you've heard it two million times over in the last few days. But do this now and it might save you an hour of work later if you happen to spot a glitch somewhere!
Plugins hiccup. Vintage hardware can get into some kind of buzzing tantrum. Maybe some stray clipping occurred that you haven't spotted earlier (refer to the next paragraph). All of those can cause the file to be rejected by the mastering engineer, so it's best to make sure it's immaculate right off the bat.
Headroom. Is it needed for mastering?
Peaking at -12dBFS instead of at -0.3dBFS makes you sacrifice 2 bits out of 24 which sounds like a lot. But told in other numbers, it's bringing the quantization noise floor from -144dBFS to -132dBFS.
Making a mix that has 132dB of dynamic range is pretty much unneeded. For example, let's say you've used just one single track with a microphone or mic preamp. That noise floor is nowhere near the -130dB range. It is more likely somewhere around -90dB mark, so you have a LOT left to leave the above mentioned -12dBFS.
What I'm trying to say is - leaving reasonable headroom will not deteriorate your resolution in any sensible way. It will make the mastering engineer's job much easier however. The transients will be left intact. The level will probably be about right to directly send to analog equipment without adjustment, so what's not to like?!
It is a skill that takes a bit to master and truly integrate into the mixing workflow, but once you make it a routine to take care of gain-staging, the mixes all of a sudden start to sound spacious and solid. Both plugins and analog hardware operate at comfortable levels and appropriately reward you for that.
Make an effort for clarity and not loudness
Modern sample-heavy productions can quickly get very loud. And loud feels good so what's wrong with that? Well, the mastering engineer will have a hard time doing their work well if the source files have been optimized for loudness.
This does not mean you turn down the master fader and call it a day. Rather that when you are deciding between making a track louder at the expense of clarity, definition and dynamics, you should think it over and not jump to the louder one, even if that usually "feels" better. It's psychoacoustics and is playing dirty tricks with your brain. You should not trust it.
Making the mix loud for its own sake can introduce some unwanted artefacts like pumping, compressor distortion or masking in the lower midrange. Those are easy to overlook in a typical mixing environment but become more obvious on a high-class mastering playback system.
This is more important than over-EQing, as EQ can be, at least to some degree, changed at the mastering stage, but overdone dynamics are much harder or even impossible to correct.
Clipping: Yes or No?
No. Well, at least not on the master bus to achieve loudness. If hard-clipping is used as a creative effect for a certain channel, that's all good. However, it's not the solution if you're hitting 0dBFS on the master fader already.
Clipping is a great creative tool for both the mastering engineer and the mixing engineer. Check before releasing files into the hands of the mastering engineer or before starting to master yourself. You should not have clipping on the output bus.
Pay special attention to clipping before actually starting to master. Clipping is usually performed at the far end of the mastering process and not at the beginning. Make sure all the transients are, so there is full freedom to decide how much to leave in during mastering.
In the end, it's your personal taste and decision but if you don't know which way to go, we warmly recommend the former suggestions.
Remove any ad-hoc mastering
With today's tools, it's easy to load up a plugin on the master bus, call up a preset and have your mix at -14LUFS in an instant. Some engineers even prefer working this way to have some instant feedback on how their mix could react to mastering.
In the case that you work like this too, take care of two things:
- From time to time, turn all "instant mastering" processors off to check for the peak level of the raw mix. If you're hitting red, back off with either the "worst offender" or generally, throughout the whole mixer.
- When you're ready to bounce the final-new-REAL_FINAL-last-mix45.wav check it. Turn all that non-crucial faux-mastering processing on the master bus off. The glue bus compressor doing 2-3dB of compression can stay, a 2dB high shelf can stay. But others most likely have to go. No limiters, no clipping, no dithering.
Some mastering engineers will ask you to remove the glue bus compressor and the shelves as well and if that is the case, it's in your best interest to accommodate the request. It is very likely that they have a need to operate without this pre-processing.
Think Big Picture
This is where the car test and its likes come into play. Mastering will not change the relative levels of different elements much, so now is a good time to try and look yourself in the eyes and ask "does this mix sound well-balanced?".
The best way to try to achieve that birds-eye perspective is to change the replay device and space. Take your export on a journey through your car, your laptop, your home stereo, anything that's not your studio. Not being able to tweak that snare a bit more gives you a unique opportunity to just listen to the song as a whole.
Use the time to spot any distracting elements that have previously eluded you.
Take notes, go back to the studio, fix, repeat. When it sounds like it practically doesn't need mastering anymore, it's done. Or maybe just another version...
How far will Plugins take you?
This depends solely on your taste in sonics. #1 hits have been made on tape machines and giant analog consoles, and completely in-the-box on a laptop. So there is no definitive answer for all situations. But from my experience, if you're aiming for "depth", "air", "glue" and the like, analog will get you there much faster than plugins.
Sometimes it's almost like "cheat code". You can try loading 4 different plugins and tweaking them for hours on end. A good hardware master bus compressor may make you go "a-ha, that's the sound I'm aiming for!" in a matter of seconds.
Send ALL the Files for mastering
If you have instrumental versions, radio edits and the like planned for release and/or future use, make those exports now. Send all those files to mastering in one batch. Once the analog chain is set up and the project loaded, it literally takes a few clicks to make all the additional versions sound the same or similar.
After three months, a plugin suite upgrade and a different mastering EQ in the chain, it's not nearly as simple. And consequently, it might cost you more.
Clicks and Pops
This one is so simple, almost a no-brainer, but so often overlooked!
It's easy to remove clicks, pops, mouth noises, rumble, and other nuisances in a single track. In fact it is magnitudes easier than it is on the stereo mix. So do your song and your mastering engineer a favor and do the cleaning chores before doing the final mixdown. The world will be a better place for it, guaranteed.
To trim, on not to trim?
The answer is not so trivial as one might think. It's good practice to leave a couple of seconds on both head and tail of the track, but what about fade-ins and -outs? Here is a general guideline:
If the song starts with a track that has some inherent noise (high-gain guitar amps and tape machines are inherently noisy for instance), leave that noise present in the leading second. This will enable noise-profiling and consequent high-quality, transparent noise reduction in the mastering process.
Apart from that, this will also enable fine-tuning the fades to match the general rhythm of the album. It's far easier to cut another eight of a second for a faster transition between songs than to try and conjure a longer fade-out from thin air.
This is, in a way, another angle of the previous two paragraphs. If you have access to high-quality de-noise tools or if some cases could even be taken care of by fine-tuning or automating the gate/expander, do it in the mixing phase on individual tracks.
The clarity in the minute pauses of instruments and lower noise floor will enable reverbs and instrument micro-details to be perceived easily and make the mix sound deeper and more three-dimensional.
Mastering a Conclusion
We hope that the above information will help you to make the most of your mixing time ! You will make healthy files for the mastering process. When mastering, you or the mastering engineer will be able to focus on the job instead of on troubleshooting and mix revisions. This will make the process shorter and leave more room for creativity and fun!
I wish you a lot of luck and great success with mixing and mastering your next big hit!