Even so, the general principles of mixing hold good. Before we look at these principles, a word about the basic requirements. Firstly, your ears. Keep them fresh (and clean, of course). Never ever attempt to mix a piece of music at the end of a long listening session. Take a break of at least an hour and preferably overnight. The human ear is incredibly good at identifying problems with certain sounds, but not if it's had time to get used to them.
Secondly, your monitoring system. It goes without saying that you should buy the best equipment you can afford. Without a reasonable system you'll have no idea how accurate an image of the music you're getting. But even if you do splash out on an amp and speakers, how do know you're getting a true picture? The answer lies in listening to your mixes on as many other systems as possible, so that you know, for example, if you're tending to mix a little bass-heavy or aren't adding sufficient top end. Finally, don't think about mixing through headphones. Irrespective of what it may say on the box, headphones do not reproduce music in stereo. They reproduce it 'binaurally', which is quite different, and makes it all but impossible to set up an accurate stereo mix.
FEEL YOUR WAY
You can take any approach to mixing you feel is appropriate to your music, from the 'wall of sound' (favoured by people as disparate as Phil Spector and hardcore guitar bands), to a cleaner, more considered approach where space is created around each instrument in terms of both frequency and time.
The latter approach is undoubtedly the more time consuming. You need a good ear to determine the area of the frequency spectrum in which each sound predominates and to prevent too much overlap. But that's what professional studio engineers and producers are able to do, and the results usually speak for themselves.
The most basic function of mixing - the balancing of levels between individual instruments (or tracks) - is not something anyone can advise you about. You know how you want your music to sound and the level controls are in your hands. But do bear in mind the likely destination for a particular mix. There's no mystery here. The primary requisite for the dance floor is a rhythm track which to hit the punters in the solar plexus. But apply the same bottom end to a song destined for someone's car stereo, and it'll cause major problems.
Bass needs to be tailored quite specifically to the needs of a particular track. Using EQ, it's possible to strip away low frequencies to quite a high level before the ear will tell you anything is missing (though this is where having an accurate monitoring system is so important). Very low frequencies are often not audible but will soak up a high proportion of a speaker's available energy. Filtering them out can actually increase the perceived volume of the audible bass and will certainly reduce distortion at high sound pressure levels. As effective as EQ is in such applications, it can be something of a mixed blessing in the wrong hands. Use it to correct minor problems with individual sounds and to create space round certain instruments by filtering out unwanted frequencies, but don't rely on it as a universal panacea. Obviously, much will depend on the versatility of the controls; sweep and para-metric EQ is much more effective at homing in on problem areas of the frequency spectrum. But they can just as easily be responsible for raising the profile of certain sounds till they just don't fit in any more.
There's no clear dividing line between the two, except to say that the ear is much more forgiving of frequencies which aren't there than those that are. So wherever possible, try cutting the frequencies you don't want, rather than boosting those you do.
WET, WET, WHAT?
One of the areas of controversy which has divided musicians and producers for years is whether to record tracks 'dry' or 'wet'. No, it's nothing to do with towelling yourself off after you get out of the bath, it's down to whether you add effects such as reverb and delay before you record them or whether you leave them dry and add your effects during the mixing process.
There are pros and cons to either approach which need to be carefully considered. Record your track with effects and they're impossible to remove subsequently. If at the mixing stage, you decide you have too much reverb on the vocals, you'll have to live with it, or re-record the performance. On the other hand, you may only have a single effects processor and want to use this for another effect on mixdown. So unless you do without the vocal reverb, you have no choice but to record with it. Vocals need reverb like England needs Michael Owen but overdo it and it's dead easy to lose the voice in a sea of mush.
Reverb often has the effect of pushing vocals back in a mix. Great for preventing them sounding like they're sitting on top of it (as they often can when recorded dry) but not so good if it's masking an otherwise excellent performance.
You can get round this by introducing a pre-delay to the reverb. This can be set up on most effects processors and can be applied to many instruments, but is particularly useful for creating space around a vocal or bringing it forward while giving it an 'aura' of reverb. You'll need to experiment with the pre-delay setting, but around 30-50ms should do. The tendency of reverb to clutter up a mix is something you need to listen for very carefully.
And it's vitally important that you choose a program with the right reverb time for each track. 'Hall' programs sound great in isolation but can clog up the music quicker than the mud at Glastonbury. Short reverbs are great for creating interesting room ambiences and don't take up as much space in the mix, but can sound unnatural. This is one argument for not adding reverb until mixdown.
When all your instruments are 'in place' you can properly assess the type and quantity of reverb you'll need. If this isn't feasible (perhaps you only have one effects processor) try to keep reverb to the minimum needed to achieve the desired effect and limit reverb times. Long reverbs often don't have time to subside before being retriggered and can accumulate in your mix like Glastonbury mud (yes I know I've said it already, but you should have seen it).
Use pre-delays if they're available and don't reject the use of gated programs. The overuse of gating effects on drum sounds in the late 80s may have contributed to their current unpopularity, but they can be extremely useful in chopping of unnecessary reverb tails and creating space. Another trick is to limit the frequency response of reverb using either your mixer's controls, or your processor's built-in EQ (if it has it). This is best done by monitoring return signals from your reverb unit and cutting any unwanted frequencies or limiting those which appear to be obscuring the sound.
PANNING FOR GOLD
The art of panning instruments and sounds to create a convincing stereo image is one of the most important in mixing, yet is frequently misunderstood. So often, you hear demo tapes where the instrument placing appears to have been carried out quite arbitrarily. It's like sharing sweets: one for this side, one for that side, and one in the middle for luck. Panning is an essential part of mixing; a means of achieving balance in your music as well as creating the transparency of a stereo image that we all take for granted in commercial recordings, but which can be difficult to reproduce.
Though I'm loathe to talk about what usually happens in a mix (if we all did what 'usually happens', we'd still be playing whistles and banging hollow logs), there are a few basic ground rules which you really can't get away from. The first is that the dominant, low-frequency instruments invariably sound better placed at or around the centre of the mix.
I'm talking here about the bass drum, the bass guitar or synth and any deep percussive instruments you may be using. Pan them too far left or right and your music will sound off-centre. Fine, if that's what you're aiming at, but there are much better ways of getting creative with your pan controls.
One of the best is to set up some interesting rhythmic interplay using your different percussion sounds. Obviously, if you're using a sample loop for the drum track this may not be possible, but you could always augment it with additional percussion (such as cabasa or claves) and pan these to the left and right. Alternatively, try setting up a delay on one of your instruments and panning the dry and delayed signals to opposite sides of the mix.
Lead vocals are also placed at the centre of mix in most recordings, though this has much to do with where you'd find the singer at a live performance. There's is certainly nothing to prevent you experimenting with the positioning of the vocals, particularly where you also have backing vocals as well which can be placed in a similar position on the opposite side to the lead vocals, to balance things out
But again, hard panning left or right of any vocal parts can be difficult to live with. I should also remind you that pan controls are not static, and there's nothing to prevent you from panning instruments left and right during a recording. It's easily overdone, but in moderation it can provide a real sense of movement (quite literally) within a mix. A more subtle alternative would be to use a stereo chorus program on a effects unit which features auto-panning. This leaves the dry signal in place, but shifts the chorusing between the left and right speakers. And talking of effects brings us back to reverb which can be used to create a convincing stereo image from any mono source.
By panning outputs left and right, you can use reverb to produce a much broader, more expansive sound, even at short reverb times. On the other hand, reverb may be upsetting your stereo imaging by changing the apparent location of a specific instrument. If this does occur, try panning the reverb to exactly the same point in the stereo field as the dry signal, preferably sticking to a mono effect.
INSTANT MIX FIXES
To round things off, how about a couple of ways to provide an instant fix for your mix? If you've already mixed down to stereo and found the result disappointing, try sticking the entire mix through an aural enhancer. Though not always successful in treating a complete mix, they can alter the overall sound in subtle and distinctive ways, particularly processors which affect the stereo imaging.
Alternatively, give the track to someone else to mix. The results may not be to your liking (at first), but I guarantee they'll reveal a side to your music that wouldn't have emerged had you been sat behind the mixing desk. What have you got to lose?
written by Nigel Lord