Those component-style graphic EQs have pretty much gone the way of the cassette deck (hipsters notwithstanding), but the EQ lives on in digital form, found in everything from phones to wireless speakers and even streaming services like Spotify. Unfortunately, understanding how an EQ works and using it properly is a much more elusive concept. You don’t want to pull a Tom Cruise and shove every slider to the max – that’s going to sound terrible. Equalizers put the power of sound sculpting at your fingertips, and as they say, with great power comes great responsibility. And while an EQ isn’t a superpower, it can get you closer to the sound you want from your gear … if you know what you’re doing. Here’s our top-to-bottom EQ guide.

Why do I want to use an EQ?

Electronics manufacturers have their own ideas about what a piece of gear should sound like, but EQ lets you have your say. Also, we don’t always get to listen to music in ideal environments. Many of us listen while commuting or exercising, where the shape of the room or ambient noise can each have a nasty effect on how our music sounds. An EQ can help.

Maybe you have a bass-heavy pair of headphones that you need to tone down a bit. Or perhaps you listen to a lot of EDM, but the treble is too sharp and needs to be pulled back. Whether you’re looking for more punch, a warmer sound, or bass that will rattle your innards, an EQ can help you dial in the sound that suits you best.

What does an equalizer do?

At its most basic definition, an equalizer manipulates frequencies. The technology first took off as a piece of analog electronics that was initially used in recording studios before making its way into the home. Whether analog or digital, an EQ is used to adjust different elements of sound to achieve an end result that appeals to the listener.

You may associate EQ with effects like reverb or echo, or popular EQ presets like “Rock,” “Jazz,” or “Concert.” But the kind of EQ we’re talking about simply offers control over the different sound registers to achieve a refined result. If used properly, EQ can smooth out audio for just the right touch, whether that means adding some beef to the low end, taking away some bite from the treble, or anything in between.

The graphic EQ – which is what we’re going to focus on for most of our walkthrough – looks like a graph (no kidding!) with frequencies on one axis and decibels (dB) on the other. From left to right, you’ll find “sliders” that allow you to adjust certain frequency bands up or down along the dB scale. Bass frequencies start on the left, with midrange frequencies in the middle and treble on the far right (like a piano).

If you’ve already got a firm grasp of what frequencies and decibels are, feel free to skip ahead to the “Playing with your EQ” section, or even our “Parametric EQ” examination (if you’re a heavy hitter). If not, the following little snippet of Acoustics 101 will probably come in handy.


All sounds — everything you hear – are essentially vibrations that we can visualize as waves moving up and down at different speeds, or frequencies. The faster the wave moves, the higher the pitch. For example, bass frequencies — such as those you hear in a hip-hop groove — move very slowly, while higher pitches (treble) like the chime of a triangle move very quickly.

Every pitch a musical instrument plays has a core frequency measured in hertz (Hz), which can be likened to a speedometer reading for the waveform. Hertz measures how many times (i.e., the frequency) a wave completes an up-and-down cycle in 1 second. If the wave moves up and down 50 times in a second, that’s expressed as 50Hz. At the theoretical limit, a human can hear from 20Hz to 20kHz (20,000 cycles). In reality, though, most human hearing tops out around 15kHz or 16kHz — the older you are, the less treble you can hear.

equalizer settings

Since all of the sound you’ll ever hear lives in this 20Hz to 20kHz zone, those are the numbers that will border your typical EQ. Most of the pitches your ears really focus on live between 60Hz and 4kHz — that’s the meat of the sound. A piano’s highest note, for instance, lives at 4,186 Hz (around 4.2kHz). There are also sounds called overtones, and an EQ will affect them, too. These sounds, which primarily live in the 10kHz to 14kHz neighborhood, aren’t something that your ears naturally latch on to, but they have an effect on the sound as a whole, so it’s important to keep this in mind when messing around with that section of the treble band.

Decibels (dB)

The decibel (dB) is the unit of measurement used to express volume level or loudness. When you move a slider up or down on an EQ, you are increasing or decreasing the loudness of that particular frequency. It’s important to know that small dB adjustments can have a big effect on the sound, so tread lightly. It’s wise to start with a 1 dB to 2 dB change and move up or down from there. Since decibels use a logarithmic scale, a 5 dB or 10 dB change represents a dramatic increase or decrease to a particular frequency band.