Mixing is the second stage in the recording process, which comes after the tracking has completed. In a basic sense, mixing isn't that hard to understand. Mixing involves blending all of your separate tracks into one stereo pair suitable for listening to on any radio, Walkman, iPod, or car stereo. Mixing also involves adding effects to polish up the sound.

The art of blending disparate sounds is very difficult. When you hear an acoustic band, the blend is taken care of for you; the reverberation is natural from the room. As soon as you start close-miking instruments, reproducing the sound in a realistic fashion becomes a challenge. While you might not know how to make a good mix yet, you certainly know a bad one when you hear it.

Mixing is all about perception. Can you perceive that this group of instruments really sounded this way? The best mixes sound natural, and they try to replicate how those instruments should blend together. If the mixing engineer has done his or her job, nothing out of the ordinary should be noticeable. That is, nothing catches your ear as “unnatural” or out of place. As you know, it's easy to spot a bad mix; there's just something “not right.”

Many engineers talk about hearing in multiple dimensions. Understanding those dimensions can help you figure out what's going on in a good mix. Here are the basic dimensions you'll encounter in mixing and what it means to work with them:

• Foreground/background: Bringing sound forward and backward in a track using volume

• Depth: Using effects to create the feeling of closeness or distance

• Up and down: Using EQ to help tracks sit in their own distinct part of the frequency spectrum

• Side to side: Placing sounds from left to right using the pan controls

Without oversimplifying the process too much, these four dimensions give you an idea of what goes into a mix. Now let's look at what goes into working with these dimensions so that you can start mixing like a pro.