Lesson 52

Advanced E.Q. Techniques

Ok... if I was stranded on an island and could only have one tool... it would probably be an EQ. You can do so much to clean up a song with skillful use of eq. Each part will have its own unique eq requirements, even if those requirements are none at all.

When used properly, an eq is a very powerful for cleaning up a mix. Let’s take this song for example. Now, I’m going to bypass all of my eq’s, and let’s hear how it sounds. Big difference. So a has a bunch of dials and you can raise or lower certain frequencies to get the sound you want. Pretty simple right? Well if that’s what you think... then this lesson is for you. I know, because that’s what I used to think. Here’s a song I mixed back when I thought I knew how to use a EQ. I recently mixed it again, with better equipment, and better skills overall now, but the single most contributing factor was learning how to use an EQ, in the mix. And that’s the crucial part, because EQ’ing a solo instrument is vastly different than EQ’ing that same instrument in a mix.

Sit down and buckle up... because in this lesson we are diving pretty deep into how to use a EQ.

It all starts with understanding how multiple sounds of different frequencies blend together, and the blind spot in our ear. A lot of this lesson is a repeat of lesson 1.3.11, on blending frequencies and the blind spot in our ear, but this lesson goes further to apply these principals to mixing.

The first concept is how waves behave when they are added with other waves. Because this is exactly what we are doing when mixing. When we put a guitar sound and a vocal sound together, we are adding the waves, but I prefer to use the word summing. We are summing the 2 sounds together to create 1 sound. In a mix, we are often summing dozens of sounds together to form one sound. So let’s take a look at what happens when waves are summed. It’s not as straight forward as you might think.

Let’s take a 40 hz wave. Here’s how it sounds, here’s how it looks on a frequency analysis graph, and here’s the waveform. Now let’s look at the 50 hz wave. Here’s how it sounds, here’s the frequency analysis, and the waveform is on the bottom, below the 40hz waveform. Now what happens when 40 hz and 50 hz are summed together? Are we going to hear both a 40 hz tone and a 50 hz tone simultaneously? No.. we will not. It is physically impossible for a sound wave to exist that carries both those frequencies. Here’s what it will sound like, here’s the frequency analysis, and here’s what the new waveform looks like. It’s not a 40 hz sound, nor is it a 50 hz sound. It’s a total mess, and the proper term for it in mixing terminology is... it sounds like crap! 

But listen to what happens as we shift to higher frequencies. 

Around 80 hz... we can add another frequency and it doesn’t sound horrible.. hooray, let’s add a third.... aaaah... noo..... have mercy.... make it stop...don’t ever subject my ears to that again!

Blah blah blah.... 

So the lesson here is that in the low frequencies, you can’t sum very many sounds together, but as you get into higher frequencies, there’s a greater ability to sum more sounds together.

Now, let me explain my blind spot in the ear theory. 
But kris you say.... how can my ears have a blind spot... they don’t see anything?
Well... ok... you got me there.... there’s not really a blind spot in your hearing... but I call it a blind spot because there’s something weird going on, where the brain makes up the sounds we want to hear. It’s kind of the same as how the brain makes up what it wants to see from the blind spot in your eye.
But kris you say... I don’t have a blind spot in my eye!! This time.. it’s me who has you. You do in fact have a blind spot in your eye... unless of course you are an alien... in which case... you can skip the rest of this lesson. But if you are human.. you have a blind spot, near the Center of your vision. Inside the eye, its where the nerve attaches to the retina. You don’t notice it, because your brain literally makes up what it thinks it should see, and puts it there. Don’t believe me... I’ll prove it to you. Close your left eye, and Keep your Center vision focused at the Center of the cross. As the dot moves from left to right, there will be a spot where it disappears completely. The dot doesn’t act disappear though, it simply goes through the blind spot, and your brain replaces that spot with white. 

So what does that have to do with mixing? Is my ear blind?
No, your ear doesn’t have a blind spot, but your brain will make up certain sounds that it thinks it should hear. In a mix, you can EQ out certain frequencies, and the brain will put them back in when you listen to the song. It’s not as prominent as the eye example, its actually very subtle, but this can be used very effectively together with the summing frequencies knowledge to clean up a mix. 
Let’s give it a listen 

Blah blah blah

Here’s how to use these concepts in the context of a mix. What I do, is I put a low cut filter on almost every track, with the cut off frequency as high as possible without being to hear its effect in the mix, or higher if it’s a low priority part. 
That greatly reduces the number of sounds being summed in that precious frequency range of 500 hz and lower. By reducing the number of sources producing sounds in that range, it increases the clarity of each one that is left, which will be the highest priority sounds, like lead vocals, guitar, snare air whatever else.
The frequency range of 400 hz and lower is the mid zone. because 100 hz is around the lower area where most instruments, and vocals begin to have sound. Below 100 hz is no problem, because you only have dedicated bass sounds, but over 100hz, you suddenly have many sounds competing for that small amount of audible space, and if it is not controlled, the sound gets muddy. And, on dedicated bass parts, where I can’t put a low cut filter to reduce its volume in the mud zone, I will normally but a bell EQ on it to reduce its volume from about 100-300 hz. I’ll use my ears, and reduce the volume in that area as much as I can without having a negative impact on the sound.


That’s how you get many layers of sounds in a mixwithout it getting muddy.