How to Save Sonic Space by Putting Less in the Mix
In Part 1 and Part 2 we discussed Subtractive Mixing and Subtractive EQ. As you learn more about using these techniques, you'll notice certain commonly occurring conflicts between instruments. Sometimes you'll encounter instruments that span more than one range. Your snare drum has both a thick low mid aspect and a bright upper-mid crack that end up competing in different families. Similarly the kick drum has a deep thud in the bass register and a crucial tap in the mids that defines your impact. In these cases the critical upper midrange band is usually narrow so you can use a deep cut with a parametric EQ set for a high Q-factor to surgically unmask the tap. Your low band will also benefit from subtractive EQ on the competing part.
Using Subtractive EQ to Carve Out Space in Your Mix
There is a special tuning, usually reserved for the studio, where a six-string acoustic is tuned to the octave notes of a 12-string. It is quite odd to play and sounds ridiculous on its own, but it is always used together with a regular six-string in standard tuning. The two instruments play in octave unison to create a lush 12-string effect. Dubbed the Nashville tuning, it is especially flexible in the recording studio. The Nashville-tuned guitar occupies a frequency range with relatively little competition, so it cuts through the final mix at very low levels. The six-string guitar is mixed in a typical fashion. Because the Nashville guitar doesn't have any bottom octave strings it doesn't mask or muddy the six-string like a traditional 12-string would. The two instruments are not competing because they occupy different frequency ranges and the result is a sparkling clean mix with great definition. Subtractive EQ functions on the same principle.
The engineer and I had just spent several hours balancing rhythm tracks but the bass guitar was still not out front enough. I asked for more bass, but he turned to me and said, "That's as loud as we can get it." He reached up and hit the solo button on the mixer for the bass channel and pointed to the meters. Sure enough, all on its own the bass guitar was right on the verge of overdriving the board. But when those other instruments were turned back on you couldn't hear it. It was the first time I'd ever seen a visual demonstration of the limits of ever-increasing volume in the mix. The bass was as loud as we could get it without distortion, but the other instruments were masking the sound. And I had just learned a lesson that was useful far beyond the recording studio.
In Part 1 of this series, we discussed the basic concept of side-chaining along with a couple of the most common applications. In this segment we'll learn about more specialized uses of side-chaining and how to set up your system for side-chaining.
The concept of side-chaining is nothing new; studio engineers and mastering specialists discovered long ago how to use one track to control others in the mix with this method. But what is side-chaining and how can it be utilized to get a better mix? Sometimes it is desirable to create a powerful mix without forcing the vocals or more subtle instruments to compete for sonic space. By using the solo tracks to control a compressor on other or the rest of the tracks, the engineer seeks to maintain a relatively uncompressed mix that automatically "steps out of the way of the solos." Subtle side-chain applications are intended to enhance the separation of instruments in the mix without drawing the listener's attention. More dramatic applications can significantly alter the feel of the song and these often become part of the sounds themselves.