Subtractive Mixing for a Cleaner Mix: Part 2

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.

Identifying and Eliminating EQ Conflicts

In Part 1 of this series, we learned how to group tracks into "frequency families" that share the same sonic space. By mixing each family of tracks individually we achieved the optimal balance for our final mix. But sometimes you encounter a pair of tracks that really are stepping on each other and you don't want to choose between them. This is when Subtractive EQ can really help, by dividing the frequency range between the two instruments.

Suppose you have two guitars in the band and they both sound pretty much the same in your front-of-house mix (a lot more common than most players realize). Unless those players are very tight and playing unison, they will lose definition in the mix and blend into the background. If they're playing counterpoint, you'll lose the precision of the arrangement. Try accentuating the midrange texture on one guitar by fine-tuning the track for the most flattering midrange, and "scooping" out the same frequencies on the other. As with volume adjustments, the loudest track on a given frequency will be prominent, so you don't have to make huge EQ cuts. Just dial back the frequency enough to duck the part out of the other instrument's way. It might be as simple as cutting slightly in the low mids on one guitar, and cutting slightly in the high mids on the other. Both will be easier to marry in the mix and have better clarity. It doesn't make any difference how they sound on their own (probably screwy). Together they make a nice clear blend.

Training Yourself to Hear Frequency Families

Take some time to listen to your favorite recordings and see if you can identify where the engineer used Subtractive EQ. Take note of the types of contrasting sounds that live well together in the mix without masking one another. Then notice how sometimes the instruments blend together to make a combined sound. These are areas where the producer chose to use the opposite technique to create a thicker sound with deeper texture. Notice that the loudest track in each frequency family still dominates, but the others can add to or embellish it.

In the Final Part of this series we'll learn common conflicts to watch for, and how to resolve them. We'll also see how you can use Subtractive Sound to get great sound right from the backline. Have you ever tried using EQ to achieve better separation in your mixes? What tricks have you discovered?

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