Here's something vital: Music breathes, and so should your mix. This doesn't mean just turning up the volume on an instrument for a solo! Your audio should always be in motion; even the slightest movement of volume levels makes the mix feel alive. Minute changes during the playback of the songs will do wonders, making your music feel more alive. It's a trick that so many engineers use. Keep those faders in motion, even just slightly. It will make everything sound better.

Automation

If you own a studio-in-a-box or computer recording system that supports mixing automation, you'll enjoy this section. Mixes aren't static. You can't just “set it and forget it” as the TV infomercials often say. A song and its resulting mix is a living, breathing thing that changes. Guitars get louder for solos, drums duck under vocals during verses; things change. If you're working on a system that you can't automate, such as a tape-based studio, or if you're using a mixing console, you'll have to know exactly what's going to change throughout the songs and adjust the levels and other parameters live upon playback. In the old days, this was called “playing the console” and was an art all to itself.

Digital technology allows you to plan all the movements of faders, effects, and pan settings in a process called automation. You go through the tracks as you mix, and you record the motion of the faders into a special track called an automation track. Once you've recorded all the movements, the automation track plays back and takes care of all of the changes in faders and so on. It's a great thing to have if you work alone. Most studios-in-a-box support some level of automation, and computer systems give you an incredible amount of control over not just volume, but all parameters of any effect on the system.

Fades

How will a song end? Take a good listen to the end of some of your favorite albums, and you'll realize that none of them just stop; they all have some kind of smooth fade. How do you achieve a smooth fade? If you use a digital system, you have a fade-out option in the editing menu and you can easily fade out the audio using that. If you have automation capabilities, just automate the master fader at the end of the tune. For those of you who have to move the fader by yourself, at the final mix down, just evenly yank the master fader to zero to achieve a smooth fade.

Using Buses

We've talked about using bus and auxiliary inputs for certain effects like reverb, but you can use buses for other things as well. A bus is simply a path that sound can take. A good example of buses is what you can do with drum tracks. Let's say you have four drum tracks that you mixed together. The balance between the drums is perfect, but they need to be a little louder in the mix. You could try to raise all four faders equally, although you might find that difficult to do. Or better yet, you could send each of the drum tracks the same bus, which would act as a volume control for all the signals it's fed. You can then easily adjust the drum tracks together either up or down.