Have you ever found yourself building an elaborate sampler or keyboard patch made up of layers upon layers only to be disappointed when bringing it into your mix? You find out that either it stands out over top of everything else, or else you need to bring it way down to a barely audible level, making you wonder, "dude, where's my sound?"
This doesn't only happen with synthesized sounds; you may have layered your drum hits, vocal takes, bass or guitar parts and come to the same conclusion.
This article will help you understand why this happens, and what you can do to avoid it, or if necessary, fix it in the mix. You will come to learn one of the central tenets of mixing: sounds that appear great in isolation don't necessarily sound good in the mix. The most common reason for why this happens is as follows:
The human ear is capable of capturing audible frequencies within a very limited theoretical range: 20hz-to-20,000hz
That is the maximum allowed "space" where all of your music must sit. It is a limited space, much like a room. If you were to picture all of your different parts in your song as if they were individual instruments in a, say, 800 square foot room, you may realize that that isn't enough room and you will have to start piling your instruments on top of eachother. This is exactly what happens when mixing sounds you've recorded that take up the same frequency bandwidth. For instance, a bass drum, and a bass guitar/synth often don't get along very well unless their fundamental frequencies are far enough apart (for instance, you have a very low 60hz [peak frequency] kick drum, and a 180hz [peak frequency] bass sound). Or, imagine needing an in-your-face vocal take, except everyone in your band insists on singing backup during the same part. The problems can become obvious in these examples, however, returning to the original issue with regards to synthesized instruments, sometimes you're building your sounds in isolation from the rest of your mix and it doesn't become obvious until too late, such as with this example featuring a layered instrument sound that sounds very full on its own.
This sound is almost a song in and of itself, from a mixing standpoint, as it contains fundamental frequencies (and harmonics) all the way from the sub-bass frequencies, up to the upper mid/high frequences. If you're not convinced, check out a screenshot of the bandwidth its taking up.
Now, compare this with just a single layer bass sound (the one we started with before layering)
And, now check out how much room this single-layer sound is taking up.
As a bass sound, it's carving out its own little place to rest within your mix, allowing ample room around it for your other instruments to sit alongside it (as long as the other instruments don't venture too much into the fundamental frequency territory of the bass sound). Keeping this principle in mind, its much easier building your tracks with single-layered, or simpler, sounds than starting with lush sound-palettes that you have to clumbsily deconstruct with EQ at the mixing stage. If you have the luxury of stripping down the layers to their most central characteristics (keep a bass bass, a lead a lead, etc), then you do have the option of going back redoing the part properly (each layer on its own track with its own volume settings).
Unfortunately, its often the case that your part was recorded to a single track during a fleeting moment of inspiration. When that happens, your choices are basicaly re-recording with a new sound, or EQ'ing the part to remove the offending frequencies and/or hard-panning, while still preserving what you liked about the sound to begin with. Speaking from experience, you will probably find it easier to go back and re-record the part than to perform major surgery that can take hours, only to yield mediocre results. So there you have it, those demo patches that made you go "WOW" and pick up that uber-expensive synth at the music shop aren't necessarily useable, and if you're new to mixing, get into the habit of building your tracks using "simpler" sounding parts that still sound good in the mix, leaving the layering for a later stage in the mix when you can bring in other instruments in order to add bit of support and fullness to your track.
