We spoke with world-renowned mastering engineer Scott Hull of the legendary Masterdisk mastering studio to help us create a simple checklist for preparing your mix before sending it off for mastering.
1. Get The Mix Right
Remember when you were recording and you said you would “Fix it in the mix?” Well, the time has come. Don’t expect your mastering engineer to be able to make sure the vocals pop or correct any issues between the kick and the bass. Since mastering engineers only have the final two-track to work with (or at most a few stems), they can’t change the sound of an individual instrument or the balance of your mix. The mastering process is more like a coat of polish than a coat of paint, there’s only so much that can be done. So make sure you’re completely satisfied with your mix before sending it off to mastering.
“It’s not important to be loud in any manner, but when your mix is completed, it needs to sound good," says Scott. "Oftentimes, the mixer wants the track to sound finished in order to get a client’s approval, which makes it really easy to get caught up in how loud it’s supposed to be. If the mix isn’t loud enough to sound competitive, you should avoid making it louder just to make it louder prior to sending it to mastering. The big mistake is trying to make it sound too finished, or as loud as everything else that you’re trying to compete with.”
2. Clean Up The Individual Tracks
On top of making sure your mix sounds good from an artistic perspective, this is your last chance to make sure there are no technical issues with your mix. Solo each track and make sure there are no audible problems like clicks, thumbs, pops or plosives. Listen for bad edits and rough fades. It’s important to identify any potential issues now, because they’re just going to get louder and more noticeable after mastering. Just be careful not to get too surgical with your EQ moves when cleaning up tracks.
“It’s really hard to undo EQ, especially narrow boosts and cuts," Scott suggests. "Some engineers will try to find issues in the mix and solve them with little cuts and boosts with very narrow bands, not realizing that they’re damaging the overall picture of the mix. It’s not just that you solved the one problem, you have to be careful that you don’t create two more problems.”
3. Remove Bus Processing
When it comes to mix-bus processing like EQ, compression and more, that’s a little more subjective. If you feel that a mix bus plug-in is adding a lot of value to your mix that the mastering engineer wouldn’t be able to deliver, then keep it. Otherwise, you should bypass everything on the mix bus. Think of it this way: If you load up your mix bus with plug-ins, what are you paying the mastering engineer to do?
Another approach is to bounce multiple versions and send both the processed and unprocessed mixes to the mastering engineer. If they like what you did on the mix bus, they can use it as a starting point. And if they think they can improve what you did to the mix, they’ll start with the clean version and use the processed version as a reference.
Scott Hull explains this school of thought by saying “If the processing on your stereo bus is in place while you’re making mix adjustment decisions, then they should probably stay. That’s a little different from what the advice has been over the last five years or so, which was ‘Turn off all your stereo bus effects, the mastering engineers know how to do it better.’ That advice kind of backfires when the mixer has been using the mix bus as a tape machine.
If the mix has been hitting an effects processor and the mixer is adjusting the vocals and the snare and so on, compensating for how the master bus sounds when you take those plug-ins off the mix sounds awful. If the mixer is making mix decisions with nothing on the master bus, that leaves the mastering engineer with the most options for the highest quality master. If your mix falls apart when you take off your mix bus processing, you may have some more mixing left to do…”
4. Check Your Levels
These days, it’s common practice to throw a limiter on the mix bus, either to make your mix sound more competitive or just to get a clearer image of what the final product might sound like. However, you should disable any limiters or loudness plug-ins before sending your mix off for mastering.
Some engineers suggest that mixes should have -3 dB of headroom for mastering, while others insist -6 dB is better. The truth is, as long as you’re not clipping or using a limiter, anything below 0 dB should be fine. However, many mastering engineers have differing opinions on this topic, so it’s best to check with them first.
“As long as the mix doesn’t hit 0 dB, the mastering engineer is in pretty good shape," Scott states. "We don’t need it to be lower than that, but if you set up your mix in the box so that your master level is -10 dB, that’s OK too. It really doesn’t have to be any louder than that. A 24-bit file has such a wide dynamic range that there’s really no reason to be concerned with peaks at -1 dB. In fact, if you give yourself extra headroom inside your workstation, your busses and your processors will actually sound better.
Many of the best mixers are putting all of that level and competitive advantage in their final mix because that’s what they send out. I’ve gotten mixes that are -.5 or -.3 dB. They’re all but mastered already. But the problem with that is, it becomes quite a bit harder to make creative EQ and dynamic changes when the mix has already been plastered like that. But, those mixes go out to A&R and producers, and if it’s not as loud as other tracks they listen to online, the mixes don’t get approved.
We’re stuck in this caveat now. The level wars are more or less over because of streaming normalization, but mixers still aren’t free to send in mixes that aren’t normalized. But, for those who haven’t been mixing as long, the same advice we’ve been giving all along still applies. Keep the levels down, and let the mastering engineer guide you to your final mix.”
5. Bounce The Final Mix
When it comes time to bounce your final mix, make sure you’re using the highest sample rate your session will allow. Whether you work in 96 kHz or 48 kHz, it’s best to leave any sample rate conversion to the pros with mastering-grade sample rate converters. When it comes to bit-depth, use the highest option possible. Even though your analog recordings will be capped at 24-bits, plug-ins and virtual instruments can operate well above that range. Thankfully, most DAWs offer 32-bit floating point options.
Before bouncing your final mix, make sure to leave plenty of space at the beginning and end of the track. It may seem counter-intuitive since you’ve spent all this time cleaning up the mix, but mastering engineers can use the dead air to isolate and remove unwanted noise such as hissing, humming or buzzing audio equipment, and even excessive room noise if needed.
“Be aware of what your DAW is doing at the top and tail of your song. Some DAWs automatically add time to adjust for delays or reverb tails, others do not," Scott says. "Make certain that your files are not clipped too close at the top of the track and make sure your reverb tails are intact at the end. Use headphones and turn up the level to hear the bottom of the fade.”
6. Listen Critically
After bouncing your final mix, it’s important you actually listen to it before sending it to the mastering engineer. Not only is it important to make sure there are no errors, like accidentally clipping off the beginning or end of the song or leaving a track muted, but this is also your last chance for quality control.
Give your track one final listen and make sure you can’t hear any technical problems. Check it out on a few different systems and see how the mix sounds. Import the bounced file into your DAW and use an analyzer to make sure there are no obvious technical issues. Throw on your favorite headphones and make sure you can’t hear any subtle mistakes. Some mastering engineers even offer mix critiques to help you dial in the best possible mix before mastering.
Scott offers that his best advice “is to reach out to your mastering engineer. I often get preliminary mixes from engineers before they print their final mix, looking for advice. It’s hard to build that relationship on the first go around, but once you do, mastering engineers can be a great resource to help you land the plane. Even some of the seasoned mixers will ask me to review something for them if they’ve just made a change like using new speakers or mixing in a new room. It only takes a minute for me to be able to say ‘Yeah, you’re on target, this sounds great’, or ‘This is something I would look at before you print the final’.”
7. Make Sure Your Data Is In Order
Last but not least, it’s important to prepare all of the release information for your track before sending it to a mastering engineer. It can be extremely frustrating for mastering engineers to receive songs labeled “Song 7 Final Mix Edit 2 Vox Up FINAL”. Make sure you know the title of the song (and the name of the album if that’s part of the release plan) and label the file appropriately.
“Naming can be a real issue. Especially when I listen to more than one version of a song," Scott states. "So it’s important to talk about good naming practices. Sending me a final mix is not a good idea when there’s a chance there could be a Final_2 or a Final_3_really_I_mean_it_this_time. I’ve actually seen that one before!
An easy suggestion is to just increment your mixes. Mix 1, Mix 2, Mix 3. Nobody cares how many mixes you had to print. And once you get close to printing the final, put the date in the name of the file, like Mix_5_9_30_2019. That way there’s no question about which mix that was when I have 12 files at my workstation. I tell my engineers to never use the word ‘final.’ It’s just not a word we use.”
Scott covers all of these topics and more on his new podcast, Making Vinyl @ Masterdisk. Follow these seven simple steps and you’ll be well on your way to hearing your music sound better than ever!