Introduction To EQ

Equalization in audio production is the process of adjusting the volume of specific audio frequencies to obtain a balanced frequency spectrum.

Proper use of equalizer can indeed make your songs sound significantly better. With it, you can cut the unwanted frequencies or boost the ones that need to be more present.

Let’s take an example. You have two bass sounds – bassline and big fat lead synth in this case. Both may have quite a bit of low end, and when you try to mix them together, they overlap causing the low end to sound blurry or distortion.

Equalization can help you here.

Take one of those sounds (most likely that fat lead synth), and decrease the volume of the low frequencies. Now that lead synth will sound little bit thinner when you’re listening to it in solo. But when you mix it with the original bassline they will sound a lot more cohesive.

The Internet is full of in-depth and very technical equalization tutorials. Instead of adding another technical guide to the many out there, I’m just going to show you how the eq affects to the sound. More like a “listen and learn” approach.

I’m going to use the Fruity Parametric EQ 2 parametric equalizer to show you what the different filters do to a sound. It’s a surprisingly good EQ and is my go-to tool for almost all of my equalization needs in my music production.

Alright, let’s get down to brass tax.

The Controls

When you first open the Fruity Parametric EQ 2, it opens with neutral settings – no boosting or cutting – with all seven bands enabled.

For each band, you can independently choose a filter type. But before we discuss the filters, look at the pic below, and I’ll explain what the controls are first:

1. Band Type Selector – This is where you select the filter type.
2. Filter Slope Selector – Use this to select how steep or gentle you want the filter slope to be.
3. Band Token – You can use Band Tokens for pretty much all the EQ manipulation you need to do. By dragging the Band Token via the mouse, you can control the center frequency (or cut-off point). You can also control the equalization level, select the Band Type and Filter Slope directly via Band Tokens by right-clicking it.
4. The Frequency Spectrum Analyzer monitors the signal and shows all the frequencies it detects in real time.
5. The Shape of the equalization curve. The eq curve is based on the selected filter type, Filter Slope and Bandwidth.
6. Frequency Controller. This is another controller you can use to control the center frequency or cut-off point in addition to Band Tokens.
7. The Bandwidth Controller controls the width of a band. In other words, the sharpness of the band of frequencies. You can also control bandwidth by using your mouse wheel when the cursors is on the Band Token.
8. Equalization Level Sliders. Use these to adjust the equalization level. You can also control the level via Band Tokens. Note that the slider is disabled for Low Pass, Band Pass, and Notch filters because they don’t use this parameter.

The Filters

Next, I’m going to introduce the filters and how they affect to the sound.

Firstly, I’m going to use a drum loop as an example of how the eq can be used to manipulate frequencies, which should make it very obvious to your ears.

This is how the drum loop sounds dry (without EQ):

There’s seven different types of filters in the Fruity Parametric EQ 2, which I’ll go over one-by-one below.

1. Low Pass Filter

This filter passes low frequencies that are below (or before) the “cut-off point” and attenuates (reduces the volume) of the frequencies above the cut-off point.

Check the sound clip below the picture to hear how the Low Pass Filter affects the sound. I’m using the following settings:

• Cut-off point frequency: 460Hz
• Bandwidth: 61%
• Filter Slope: Gentle 6

2. High Pass Filter

The High Pass Filter passes high frequencies that are above (or after) the cut-off point and attenuates frequencies that are below (or before) the cut-off point. It’s the exact opposite of Low Pass Filter.

The High Pass Filter is good for removing low frequencies from sounds. Check out the audio example below to hear what it sounds like. Here’s the settings:

• Cut-off point frequency: 460Hz
• Bandwidth: 61%
• Filter Slope: Gentle 6.

3. Band Pass Filter

The Band Pass Filter allows only a range of frequencies that are around the center frequency to pass through in a shape of a bell and attenuates the frequencies that are outside the center frequency on both sides. Here’s the settings:

• Center frequency: 512Hz
• Bandwidth: 61%
• Filter Slope: Gentle 6

4. Notch (Band Stop) Filter

The notch filter attenuates the frequencies that are around (on both sides) of the center frequency and passes through the others. This is opposite to the Band Pass Filter. Listen to the audio clip to hear it in action. Here are the settings:

• Center frequency: 512Hz
• Bandwidth: 61%
• Filter Slope: Gentle 6.

5. Peaking Filter

The peaking filter either attenuates or accentuates (boosts the volume) of a range of frequencies that are around the center frequency. It’s good for cutting or boosting specific frequency areas. Check out the example sound below. Settings:

• Center frequency: 1721Hz
• Bandwidth: 46%
• Filter Slope: Gentle 6
• Band Level: 9.1dB

So basically I boosted the frequencies around 1721Hz about 9.1dB.

5. Low Shelf Filter

The Low Shelf Filter attenuates or accentuates the frequencies that are below (or before) the cut-off point. It’s similar to a High Pass Filter – cut the low frequencies and let the highs pass through – if you use it for cutting. The results are more-or-less the same.

But you can also boost with it. I like to use it for boosting low frequencies when needed. Here are the settings I used for the audio example:

• Cut-off point frequency: 511Hz
• Bandwidth: 49%
• Filter Slope: Gentle 6
• Band Volume: -16.7dB.

I cut the frequencies starting from 511Hz and below about -16.7dB.

5. High Shelf Filter

The high shelf filter is the opposite of the Low Shelf Filter. It either cuts or boosts the frequencies that are above (or after) the cut-off point.

If you use the high shelf filter for cutting, you can achieve the same results as you can with a Low Pass Filter. In the example below, I’m using a High Shelf Filter to boost the high frequencies and add brightness. Here are the settings:

• Cut-off point frequency: 511Hz
• Bandwidth: 46%
• Filter Slope: Gentle 6
• Band Volume: -16.7dB.

I cut the frequencies starting from 511Hz and above it about -16.7dB.

Multiple Filter Types

With the Fruity Parametric EQ 2, you can use seven different bands simultaneously, and each band can have a different type of filter.

In the pic below you can see I’m using one Low Shelf Filter, five Peaking Filters, and one High Shelf Filter.

Check out the audio example to hear what the EQ settings below sound like on our drum loop. (Sounds weird, yeah, but it’s just an example).

Wrapping it Up

You should now have a rough idea of what the different filters do to the sound.

The filters I use the most in my productions are the High Pass Filter, Low Shelf Filter, High Shelf Filter and Peaking Filter.

I use the high pass filter when I want to CUT low frequencies from instruments that don’t need to have them. I use the low shelf filter when I want to BOOST the low frequencies (like on a kick drum or bassline for example).

I like the high shelf filter for boosting the high frequencies to give brightness and clarity to any instrument that may need it.

The peaking filter is what I use to boost narrower frequencies of different instruments to help them cut through the mix. I also use it to detect and cut problematic frequencies by setting a narrow Bandwidth, boosting a few decibels, “sweeping” through the frequency ranges, and once I hear the problematic frequency, I’ll cut it out.

Before I go, I recommend checking out this article, which includes an equalization “chart” that you can use as a starting point for all your equalization needs.

And finally, here’s the tutorial video.