7 Tips on Prepping Your Mix For a Better Master
Mastering music is comparable to looking at a mix through a magnifying glass. A good master will enhance all the juicy and tasty parts of the mix making the mix sound bigger, brighter, and just better over all. But it is a double-edged blade...mastering will also bring out critical problems in the mix and make them more noticeable. Don't get me wrong, a good mastering engineer can fix a lot of frequency problems and can get pretty creative with some Mid/Side processing, but for the most part it is up to the mix engineer to fix any problems like bad edits, harsh voices/tones, and muddy low end frequencies. Mastering engineers are like the polishers. We make it shine! So if you give us a turd...well... you know how the saying goes.
I get a lot of mixes in from many different mixers with many different styles. And to be honest, I have noticed something... most mixers fail to hit the mark when it comes to prepping the mix for mastering. This costs money and time-ultimately causing the project to fall behind schedule. It is for this reason that I decided to write an article on how to prepare your mix so that you get a rockin' master back from your engineer in a timely fashion.
Free plugin used in this article: Voxengo SPAN
My SPAN Setting and How it should look when playing audio through it.
*Span should be inserted on your master output channel.
*On the display above you will notice that SPAN is now showing a high definition frequency spectrum. The filled in lighter green line is the real time average RMS level. The darker green filled in line is the real time peak level. And the orange line at the top is the max peak hold levels.
*The following is assuming the track is already mixed and ready to send off to the mastering engineer.
1. Double Check All Edits / Print Down Any VI Midi Tracks
You know how after you have a gig and you are packing up your stuff from the club, there is that one last thing we performers have to do...(unless we are too drunk - in which case your band mates do it for themselves but don't look out for the lowly bassist, while his brand new Warwick Corvette-4 Bass walks off with another band from Oklahoma...yes, it still hurts..)
I am talking about the all mighty "Idiot Check." An idiot check is when you do one last pass through a venue/job to make sure you didn't leave any of your gear/tools behind.
Unfortunately, there is no easy way to do this is when it comes to checking edits. This step requires you to listen to any stems that received heavy editing in solo...one by one...I bet your probably going.."Well, Clint... I do all the editing finalization when I am actually editing." And I get it, same here...but, it never hurts to do one last "idiot check" on your mix before you pay another person to help you find out that you missed something.
This is a perfect time to also finalize any Virtual Instrument tracks and commit them to audio. If you are not doing this, it will come back to bite you in the butt later on...trust me. Get into a habit of printing your midi tracks to audio upon finalization of processing, this way if you lose your sample library (i.e. your sample drive crashes, walks off) you don't have to dig that sample back out of the internet just to re-link it. Plus this makes for a safer bounce...so do it!
2. Make Sure There is No Clipping - Anywhere and Bring Peak Level to between -6 and -3dB
Okay... you may be saying to yourself, "Clint...I know there shouldn't be any clipping! What do you take me for? Some sort of conjurer of cheap tricks?!"
All Gandalf references aside, it is easy to miss some clipping, especially when you start stacking the plugins on. One option is to literally insert a meter (or use built in meters) between every plugin...but that is not thorough enough for me. Here is what I do at the end of my session to make sure the mix is clip free and to peak target.
First, I will delete any plugins that are turned off or I am not using. This means that ultimately, I decided against using it so I don't really need it anymore...plus, they are taking up RAM, so... yeah.. nuke 'em. I'll play the song through and make sure there are no overages on each track. I will then loop the part of the track that has the highest peaks, leaving a lead in from a verse or section that isn't as loud, select all of the individual tracks and level them (all together) to sum up to -6 to -3dB on the master meter provided on SPAN. Do not use the master/subbus fader to level your mix - you want signal going out at line level. Always level your individual tracks to get your summing track to target.
Last but not least, when doing this stage you should be looking at the SPAN (inserted on the master channel) and trying to get all frequencies to their correct level. This may mean I have to do some EQing on individual tracks. The idea is to get the RMS levels to create a "grassy knoll" that rolls down to the right like in the picture below. The cleaner and smoother you can get this curve, the better the mix will sound. If you have an instrument that is poking out of the field higher than the rest of them you can turn it down, or use multi-band compression to control that range on the instrument if fading down isn't an option.
3. Route Everything to a Sub Bus
You may already have this set up as a template, in which case... I commend you for using good habits! But if you do not use a sub bus (a summing/processing channel for all output tracks), I would highly recommend using one instead of doing any processing on the master channel.
Having a sub bus allows you to do some things that processing the master channel will not. For one, you can run parallel processing along side of the sub bus into the master. This means you can do things like use parallel compression or harmonic excitement on your whole mix. Routing everything to a sub bus to be lightly processed before printing is the way the pros do it. Be like them and use a sub bus!
4. Balance Left and Right / Check Track Pan
Now that the levels are good and I have a sub bus, I will begin to make sure that the balance between sides feels good. You can use a few different plugins on the master channel to help you get an idea of the stereo content like my personal favorite - Hofa's Goniometer, but you can also just take a quick glance at the master meter on the SPAN and see if one side is louder than the other. If so, roll up them sleeves... 'cause we got work to do.
The first thing I will try to do if the stereo balance is off will be to go through each and every track, including buses, and listen to all sections of the song while solo'd. I am looking for phase and lopsidedness in each and every track and group of tracks. This should take some time. Make sure it is quiet (I hope it is pretty quiet in your studio - well when you aren't tracking at least) and listen carefully. Use visual aides like stereo meters and the Goniometer to help you identify phase and balance issues. You would be surprised how much this one step can help a broken mix!
Once an offending track is identified, I will correct the problem with a stereo imager which comes standard in most DAWs. Usually, in my mixes, the culprit is the guitar bus. For some reason, when I have to go back and re-balance pan, I find myself coming back to it. Once I have everything balanced via pan and width, I will then drop a width tool like BX Control from Brainworx on the sub bus (1st in the chain) to control the overall width of the track.
5. Sub Bus Processing - EQ and Compression
I can hear many of you saying..."But Clint, everything we have ever heard from other mastering engineers to NOT use processing on the whole mix." And I am here to tell you, as a professional mastering engineer, that is hogwash. As long as you don't destroy your mix with the processing, it actually helps the mastering engineer to do some sub bus processing.
When it comes to EQ (second in the chain), you just want to enhance the mix, you are not looking for huge moves here. The most I would do would be 3dB of adjustment. If you find yourself having to move the gain more than 3dB up or down, you most likely need to go back to section 2 in this article and level the mix a little bit more. This is also a great time to do some selective notching of unsavory frequencies.
Okay, so now you have the mix balanced, leveled, cleaned, and edited...and it sounds great because of the EQ we just inserted! Perfect! let's make it sound even better now! One thing I like to do is run a multi-band compressor right after the sub bus EQ. Specifically to control any rogue frequencies that decide they don't like their home and want to take off. These frequencies usually come from the vocal tracks as they tend to be the most dynamic sound in the mix.
The trick to compressing the whole mix is simple...just barely kiss the peaks with the compressor. The goal is to contain, not shape the signal. I'll throw a compressor (preferably a multi-band one) on the sub bus and bring the threshold down until the GR meters barely react to the signal from their respective bandwidths. 1 to 2dB of GR max per band. Then I will adjust attack/release settings and bring the output up to match the input. What this will do is essentially "catch" any frequency spikes and control them a little more. Since mastering is basically like sticking your mix through a play doh factory, you may as well start the wrangling now. FYI, big spikes make compressors and limiters act like they are drunk, incompetent fools.
6. Printing Your Mix Down Properly
Okay, we are on the home stretch!!! Ultimately, numbers 6 and 7 could have been on the same section, but I like the number seven way more than I like the number six..so yeah.
This one is easy, but if you are used to bouncing offline it may seem like a pain in the butt at first. I highly recommend bouncing live, or printing the final mix down to a new stereo track via real time recording.
There are mainly two reasons for live printing...The first is that you can actually hear the bounce happening in real time, so if there are any audio errors you will be able to identify them. I am speaking from experience here. I have humiliated myself a time or two by sending broken and glitchy files to other professionals so bounce in real time or at least check your bounces all they way through if you insist on using offline bouncing.
The second reason is only available if you print down your mix inside of the session, which is what I do and what I suggest everyone does. And the reason is this: You will have a high res version of the current mix saved to a track in your session. Any other versions would be recorded on to new tracks, thus saving each and every version of your mix inside of your session for quick recall and reference. Audio geniuses do this, so should you!
For those that may be new or need a little help with setting this up, it is easy. So if you have followed these steps up to now, you should have everything that was going to output going like so: stems/effects/buses > sub bus > master output. And if you do then the next step is super easy. Create a new stereo track and assign the input to a stereo bus that is not being used. Then, assign your "Sub Bus" outputs to the same stereo bus. Name the new stereo track, arm it, and hit record! Viola! you should be now recording your mix with all effects into your session on a new track that does not route back into the sub bus. Then of course, when you want to go back to mixing, reset the bus routing back to your output and mute or power off the newly created stereo mix track.
7. Exporting The Final Mix for Mastering.
And here we are...the last step! Phew! That was a lot to cover considering all we are doing is getting ready to send our track to the mastering engineer! But at least we know that we are doing it right, which will ultimately save us money and time! (You can shower me with gold and riches now..ha ha just kidding...not really.)
So the last step is pretty standard, but occasionally I will get a mix from an audiophile or tech-head and it is at 32 bit float and 192kHz wav. Or I might get a FLAC file. On the other end of things, I have had many people send me mp3s to master...really?!...mp3?...AAAARRRRRGGGH! Needless to say, don't do that; mastering engineers hate it when someone sends them an mp3.
So what do we want? Well, I can't speak for all mastering engineers, but I know what I like... and it is a 24bit/44.1k to 96k wave file. I don't like Apple lossless or AAC, FLAC, CAF, or any other format. And...I bet that most mastering engineers are with me on this one. The most common submission, and one that will work for anyone is 24bit 48kHz. This PCM setting is also what video sound is synced to... Plus it is the perfect match for size/quality. All of my project templates are set to 24b/48k. I have had no issues with CPU/RAM/HDD and all the files sound great....works for me!
And there you have it! A mastering engineer couldn't ask for more (at least this one couldn't). If you do these seven things when wrapping up a mix you will be guaranteed to get your master back quickly and pain-free. Happy mixing, and please comment or share!-because you're cool, like "The Fonz."