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Twice a month we revisit some of our reader favorite posts from throughout the history of Audiotuts+. This tutorial was first published in December 2008.
Knowing how to use an equalizer is a fundamental skill for anyone working with audio, yet it is one of the most abused. Here are some tips and tricks for using your EQ more effectively. You’ll notice there are more don'ts than dos on this list; that’s because EQ is best when used in moderation.
Step 1: Find The Frequency
Finding the right frequency to adjust is, of course, the most important thing. With time, some of the more common frequencies become second nature, but what if you’re dealing with a new sound, or just don’t have the experience to know where to start? Here is an easy way to find the right frequency every time.
What you need is a parametric EQ, or at least an EQ that allows you to control the target frequency. Boost one band all the way. If the band has a “Q” control make it quite high (Q stands for “quality factor” and it controls how much on either side of the target frequency is being affected).
Then, play the sound and slowly sweep the frequency back and forth until you find the point where the tone you are looking to focus on is loudest. Make a note of the frequency and put the EQ back to zero. You now know the frequency where your target tone occurs and can cut or boost appropriately.
In the audio samples below we have a fiddle track. The first sample is the track as is. The second sample is using this technique to isolate the croak of the box against the strings.
Example 1 - Fiddle without EQ
Example 2 - Fiddle with EQ
Step 2: Think First, Record Second
Before you hit record think about where this instrument is going to sit in the mix, and what it needs to accomplish. For example, an acoustic guitar in a two-piece band will need to be fairly rich and full. But, if an acoustic guitar is part of a ten-piece band, then any fullness will be buried and will just end up contributing to a muddy mix.
These two situations require very different tone, and so therefore should be recorded differently. Take time at the very beginning of the recording process to think about what role every instrument has in the mix and plan its tone accordingly. This should affect your choice of instrument, mic, mic placement, and what sort of room you choose to record in.
Step 3: Understand What You Need To Worry About
Don't waste your time and energy. It's important to understand that it's okay if an individual instrument sounds terrible when you listen to it by itself, as long as it sounds great in the mix. Any individual track only needs to sound good on its own if you hear it on its own at some point in the song; otherwise all that matters is how it sounds in the mix.
In fact, the qualities that make an instrument sound fantastic solo, are often the ones that make it hardest to polish in a full mix.
Step 4: Don't "Fix In The Mix"
EQ should be the last resort. That is to say, try to get your tone as perfect as possible right from the beginning. If you've followed step 2 then you're half way there, but don't fall into the "I'll fix it in the mix" mentality. If you're not completely happy with the tone you're getting without an EQ then keep trying.
Mic placement can be one of the biggest factors here. Don't be afraid to spend the time trying as many different placements as necessary to get the right tone. Keep in mind that small changes in placement can make a big difference. If you have great tone from the start, then EQing during the mixing process will be little more than massaging the sound into place.
Step 5: Cut Narrow, Boost Wide
It's a good rule of thumb that when cutting it's best to use a narrow (high) Q, while it is better to have a wide (low) Q when boosting. This will help keep your EQ subtle.
Step 6: Make Cutting Your First Instinct
There are two reasons why it is better to cut than to boost. The first reason is that excessive EQ boosting in a mix usually results in muddiness and loss of clarity. The second is that too much boosting can lead to phasing problems.
In a nutshell, phasing problems occur when waveforms get slightly out of alignment. The result to your tone can be drastic and is generally very undesirable—but I'll leave the details of phase for another tutorial. Boosting should be done sparingly.
Step 7: Check Into Low-Mid Rehab
Hi, my name is Mark and I'm a recovering low-mid junky. The low-mid range is where all the fullness and body lies for many instruments. For this reason it can be tempting to give those instruments plenty of low-mids. The problem is that all those low-mids fight for room in the mix and if you aren't careful you'll be left with a muffled, unintelligible mess.
This problem is furthered by the fact that the low-mid range is an overlapping point for many of the instruments most common in modern music. The chart below shows the approximate range of some common instruments, including their harmonics. You'll notice that the low mid has a lot going on. Be aware of what's happening in the low-mid range of your songs and use the EQ appropriately. In some cases it may be necessary to change the arrangement or instrumentation of a track to avoid a low-mid mess.
Step 8: Make Room
Think of your mix as a physical space. The more you put in that space, the smaller the items need to be to fit nicely. So, the more instruments you put in your mix, the harder it will be to fit everything in.
In step 6 we talked about the pile up that occurs in the low-mids. Well, with each additional instrument in a mix, the more important it becomes to keep an eye on the areas where their tonal ranges overlap (look again at the chart from Step 7). Each instrument needs its own place to sit in the mix, so any time there is a common range you need to pick which instrument takes the forefront in that frequency range.
For instruments that have the same basic range, such as bass and kick drum or two guitars, you can use the EQ to interlock them making them both distinct.
This means that any frequency boosted on one should be cut in the other and vice-versa. In the example of a bass and kick drum, if you boost the thump of the bass (100 Hz) then cut at 100 Hz from the kick drum.