First, learn everything you can.
And then
throw out the rules.
By that I don't mean forget everything you just learned -- but that rules are just guidelines.
Mix by your
ears -- not by settings or rules you've learned or set up. (Doesn't hurt to keep an eye on the meters, though.
)
Everybody's advice above is good.
A trick that may help you to create a more defined mix that suggests real people playing in real space is to
visualize your
stereo mix in three dimensions.
This involves a little mental shenanigans, though.
Obviously, there is the left-right axis defined by the stereo speakers. And it's not too much of a leap for most of us to see that, by judicious use of reverb and echo [which should
not be treated as the same type of phenomenon] you can help create the psychoacoustic image of front to back depth.
But what about the third,
vertical axis? That's where the mental trick comes in. You need to get in the habit of visualizing this as the spectrum from bass (at the bottom in my view, but I
suppose it's arbitrary and you
could visualize the bass on top) to treble (at the top in my schema).
While this is sort of an artificial conceit it can help you get into the habit of making a "space" for every instrument, voice and sound in the 3D matrix you're imagining.
So, for example, you can have a piano on the left and a rhythm guitar on the right -- and while, if these two instruments were 'stacked' in the same left-right position they'd mask each other's detail and definition, because they're separated in the stereo spread you can hear each clearly and they complement each other.
Now, you can also put, say, some high strings or a high organ part on either or both sides (who wants strings on just one side? Well, never say never)... and if there's not too much frequency overlap with the piano/guitar you'll still have clearly defined instruments.
Of course, this is a working metaphor. You might not be able to separate two similarly pitched instruments that exist in the same left-right space just by adding reverb -- but if you move one of them a bit on that axis you'll get more psychoacoustic definition than if you hadn't added the verb. (Also remember tha in
most environments the farther
back a sound is the closer to the center it will normally be positioned. (Sort of the audio equivalent of perspective.)
And, finally, back to the echo vs. reverb thing. The interplay between echo and reverb is extremely complex (and you've probably noted that many satisfying reverb patches do use some predelay echo). But -- and this is a
rough rule of thumb just to use as a jumping off place -- you can generally think of reverb as "positioning" a sound back away from the listener. But you can sometimes push a vocalist or lead instrument forward with a subtle (or not so) use of echo (with less or even no reverb). When done over agressively this can sound pretty fake -- but even then it can be satisfying. But, done with discretion it can shove a vocal forward in the mix in such a way that it sounds like it's almost in front of the speakers. (Also, you can use more echo if you gate the echo to eliminate or at least attenuate the echo trail that lingers after the original sound.)
Also, on subtractive EQ --- it's a very good rule of thumb because most beginning engineers end up turning up the bass and treble on EVERYTHING. But, as always, ultimately you should be guided by your ears... not where some white line is on some knob. One key:
don't get in the habit of soloing sounds when you EQ them. Listen to them in the mix when you're EQing -- because you're trying to get the sound to "seat" itself in the mix.
A good example is acoustic guitar. If you have a solo acoustic you want it full, with plenty of bass and plenty of sparkle too, since it's got to stand in for "the whole orchestra." But -- in a typical rock or country mix -- that acoustic guitar is probably only a chunky rhythm element. You'll almost certainly want to shelf off the bass with a high-pass filter -- and, depending on the situation and mix, you might even want to roll off some highs, too, if the guitar conflicts with other instruments or interferes with vocals.
Did I mention you should use your ears... ?
