Mixdown Lowdown (Part 3)
The concluding episode, and Paul White explains how the processing secrets already revealed can be applied to make a complete mix. No more staring at the faders in despair...
In this third and final part, we examine how the recording techniques we've already examined are applied to form a complete mix.
NOW THAT YOU'VE experimented with all the techniques we've discussed in the first two parts of this series (and perhaps many more), it's time to settle down at the desk for a hard day's mixing. Before you start, though, it's a good idea to sketch out a track sheet so that you know where everything is, and have a Chinagraph pencil handy to scribble on the mixing console. I won't regale you with all the usual waffle about cleaning and demagnetising your heads, as I'm sure you don't need to be told.
So, let's load up the tape and run it through first time with all the EQ on the desk set flat, and the pans centred. This should give you an idea of what tonal corrections are needed, and once you've set up a rough balance, you can start thinking about positioning the sounds within the stereo field.
Bass instruments are traditionally panned at or near to centre, for several reasons. First, bass sounds contain a lot of energy and most of the work done by the hi-fi system at the end of the chain is in reproducing this sound. So it stands to reason that you'll get more volume if the bass is coming from both speakers equally than primarily from just one of them.
Second, there's the fact that the human brain tends to perceive low-frequency sounds as coming from no apparent point source in any case, so even if you do place bass noises in extreme positions, it's unlikely many people will even notice that they're there.
And third, when a vinyl record is cut, grossly different amounts of bass energy on each of the left/right channels, or large phase disparities at the bass end (which amounts to more or less the same thing in practice) can cause severe problems. The stylus of a record-playing cartridge decodes the two channels of sound by responding to movement in two axes, and because bass sounds correspond to large stylus excursions, any difference between the two channels in this region will provoke the stylus to jump out of the groove. Clearly not a good thing.
Some cutting rooms get around this problem by summing all the low frequencies to mono when dealing with a particularly troublesome cut, but this can alter the sound of the mix due to possible phase cancellations and so on. Heavy flanging on deep bass sounds can cause similar problems. The moral is that it's best to get it right to start with, and a spectrum analyser can be a great help here.
Now that you've heard how the mix hangs together, patch in compressors to handle anything that's bobbing up and down in level (the biggest culprit here is likely to be vocals). Likewise, check every channel (using PFLs if you have them) to see if any of them would benefit from gating to improve noise performance.
If your initial recording was good, you shouldn't have to use too much EQ to get things sounding as you want them, but you may want to patch in a psychoacoustic enhancer to add a bit of sparkle. This may be done on individual channels by patching it into the insert points, but to brighten the whole mix, you'll need to use master L/R inserts, or alternatively enhance the whole mix on its way to the mastering machine.
If you have parametric equalisers or even just a sweep mid control, you can experiment with tuning the EQ to the basic pitch of some of your drum sounds. and then adding some boost. This gives a drum sound similar to that featured on the Dire Straits Brothers In Arms album, which doesn't sound particularly natural, but is very clean and tight with a lot of separation - ideal material for CD owners who like to think their music sounds more realistic than anyone else's.
Once all this has been done, you can think about treating the sounds in various ways.
EFFECTS ARE WONDERFUL things that can make or break a mix. You're trying to present the piece of music in its best possible light, and your treatment must be sympathetic to the mood and style of the piece of music you're mixing. After all, your aim shouldn't be to show off your new studio toys, but to do whatever's best for the music.
OK, so it's always tempting to overdo things like reverb and echo, especially if you've saved up all your beer money over the last year for an effects unit and it's just arrived. But by adopting the tricks discussed earlier in this series, you should be able to create a sound perspective which is truly three-dimensional, without anything being too obvious. As with conjuring, it's the illusion that matters - not the mechanics of the trick.
"It's always tempting to overdo reverb and echo, especially if you've been saving all your beer money over the last year for an effects unit and it's just arrived..."
Now, some styles of music thrive on spectacular effects, so you shouldn't be afraid to use them once you are convinced that they're necessary. For instance, what currently masquerades as "New Age" music is often sparse and ethereal, so long reverbs can be used to great effect without getting in the way. In some cases, it may be an advantage to roll off some of the bottom end on the effects return channel, so that the reverb doesn't get too boomy and cavernous. Otherwise, just go for it and have fun.
Getting a balance between sounds is ultimately a matter of taste, and don't let anybody tell you otherwise. But as an example of the sort of point you should look out for, it might be a good idea to mix strings sounds a lot lower than you might first have thought - they have a habit of pushing themselves to the surface no matter how deep you bury them. Let them take over, and your track can easily turn into a swamp.
Talking of swamps brings us onto that bastion of modern popular music, heavy rock. This can be pretty difficult to mix, especially if there are two guitars - it's likely that both will have similar tones and be heavily distorted, and that each player will want to be louder than the other.
Your first line of defence is to pan the two guitars to different sides, and then modify the EQ slightly so that they don't quite sound the same. Even so, problems can arise when the vocals come in, as these may need to be louder than you'd like them to be just to cut through. The same may be true when the inevitable lead guitar solo comes along - and instantly sinks beneath a sea of electric chainsaw rhythm guitar.
One fairly elegant way around this problem is to feed the rhythm guitar track(s) through a compressor, but control the compressor from its key input, into which is fed the vocal and, later, the lead guitar solo. If the compressor is set up properly, the presence of the vocals will cause the level of the rhythm guitar to drop, and a suitable release time (try half a second to start with) will allow its level to be restored between phrases. This will pump slightly, but in the context of heavy rock music, it'll actually add to the illusion of power and volume (and is often used to create that very effect). Pull the same trick during the guitar solo, and you can lift the lead line out of the mix without it being too loud. Make no mistake: this is a powerful technique, and worth experimenting with.
The business of adding an effect (usually echo) to odd words or sounds is one that confuses some people. The way to do this is not to turn up the effects return control at the appropriate point, but to turn up the effects send just before the word or sound in question occurs, and then off again straight after. This way, only the chosen word or sound is fed into the echo unit, and you don't get bits of any preceding or following words in there to mess things up. And you don't run the risk of chopping off the echo decay, because once the sound's in the echo machine, you can do what you like with the send control and you won't cut it off (the decay is determined by the delay time and the feedback setting alone).
But try not to overuse this trick. As an engineer, I come across many inexperienced bands asking for just this effect at the end of vocal lines, or at the end of the song. Once is great; often is not so clever.
IN AN IDEAL world, every instrument and every voice would have its own track on tape, but the limitations suffered by those of us with less than infinite amounts of money to spend on our hobby often preclude this. You have to bounce tracks to make the best use of the number of tracks available, and this often means that the drum track ends up in stereo or even mono. And if you didn't apply effects during recording or bouncing down, then the treatment of these composite tracks is at best something of a compromise.
Even if you've realised the advantages of a MIDI sequencer synced to tape and incorporated one into your system, you may well still be limited by a drum machine with no separate outputs - so you end up in the same boat. Another problem you're likely to face with this setup is that you run out of mixer channels.
But let's look first at the problem of having several instruments on one track. Obviously you can't treat the individual instruments on a composite track separately, and the same goes for the drum machine that has only mono or stereo outputs. The only option in this case is to choose a subtle, ambience-type treatment which will add width and presence to the track; a more severe effect may complement some of the sounds, but not others. Adding much in the way of reverb to a drum machine will lead to a cluttered sound (due to the effect of the reverb on the bass drum), but a short setting can still work well. Likewise, if the track warrants it, you could use gated reverb on the whole drum-kit without it sounding too odd.
"Mix strings sounds lower than you might first have thought, as they have a habit of pushing themselves to the surface no matter how deep you bury them."
Having said earlier that there's no way of adding different effects to different sounds of a composite track, there may be a way around this in the context of a drum track, depending on the tone and relative levels of the drums in the mix. If you have a gate with a side chain filter or can patch in a separate equaliser. you may be able to persuade the gate to open only for the snare drum but not for the rest of the kit. This entails carefully setting the Threshold and Filter controls: set the gate to a fast attack and a release time just long enough to let the snare drum through before it closes, and then feed the output of this gate to your reverb send. In this way, you may be able to get reverb on only the snare drum.
If your gate has a Depth control that enables some signal to pass even when the gate is closed, you can have a small amount of reverb on the kit all the time and more on the snare drum beats. This may sound better than heavily reverbed snare in the middle of a completely dry kit.
Other composite tracks such as mixed synth lines can be given treatments such as flanging or chorus on one side and dry signal on the other, or a slightly detuned pitch-shifter treatment to fatten them up; but excessive use of reverb should be avoided, as again, it can make the mix sound incredibly messy.
Now we come to the last problem running out of mixer channels for sequenced instruments or additional effects returns. Even if your mixing desk has eight or 16 program busses, when you come to mix, most things are routed directly to the stereo buss. But you can add a simple "something into two" PA-type desk, feeding it into two channels (or two aux returns) panned left and right, and thereby greatly increasing the flexibility of your setup at a relatively low cost. If you don't want to run to a fully-fledged separate mixer, there are also rack-mount line mixers available which will do the job without necessarily taking up too much space or cash.
Don't forget, either, that you can use the tape monitor channels on some desks as extra inputs when you're mixing, and though these may not have any EQ, you may be able to do without it or patch in something from your rack to help out.
A final area of compromise worth discussing concerns tracks that are used for vocals, say, but which also carry the guitar solo in the instrumental section. The problem here is that while both signals invariably need different treatments, you may not have time to reset all your effects sends, EQs and so on when changeover time arrives.
The simple answer is to use a split lead, and feed the signal into two separate mixer channels, setting up each one for each of the two sounds being treated. This way, you can use different effects, EQ and pan positions, and even patch different processors into the channel insert points. You can then switch quickly between one and the other when the time comes, simply by using the channel faders or the channel mute buttons.
BEFORE WE FINISH off, there are a few more points that need stressing.
Before knocking your two-track machine into Record for the final take, put down a tone at the start of your tape at OVU from a test oscillator running at around 1kHz (or from a synth with a pure, steady tone about an octave above middle C). This will help when you come to copy cassettes from your master, as you'll have an instant guide to the input level without having to search for the loudest section.
If you're going to have a master cut from your tape, you should include all the test tones recommended by the APRS, and also stick to their conventions for leader tape colouring and length.
And appropriately, right at the end fadeouts. If you're going to use a fadeout, don't forget to start it in good time, because they always take longer than you expect, and there's nothing worse than finishing a clean mix, only for the tape to run out halfway through your fade. A typical fade may take between 15 and 30 seconds, so allow for this at the recording stage and you'll save yourself a lot of frustration.